# 4 stop&start stations to control 4 motors...



## Hugo (Feb 21, 2011)

hello in new to this filed and doing great so far but now im faced with a challenge i need to 
draw a schematic for a 4 stop and start P.B. stations to control 4 motors with interlock and any two motors running at anytime with the other 2 to remain off 
now i have been trying to draw this out as best i could but i keep getting my contacts in the way i know i need to use N.O contacts on my contact relay.. if anyone can shoot me a schematic or maybe even some tips would be great full:thumbup:
thanks
[email protected]


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## sparky970 (Mar 19, 2008)

Let's see what you have drawn up.


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## John Valdes (May 17, 2007)

I have no way to draw it and post it. Or should I say it would be an inconvenience. Like sparky said above. Show us what you have drawn and we can critique it. If you post your drawing we can edit it too if you want.


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## oldtimer (Jun 10, 2010)

Hugo said:


> hello in new to this filed and doing great so far but now im faced with a challenge i need to
> draw a schematic for a 4 stop and start P.B. stations to control 4 motors with interlock and any two motors running at anytime with the other 2 to remain off
> now i have been trying to draw this out as best i could but i keep getting my contacts in the way i know i need to use N.O contacts on my contact relay.. if anyone can shoot me a schematic or maybe even some tips would be great full:thumbup:
> thanks
> [email protected]


 Please punctuate, and spell correctly, then, we may be able to help you!


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## HARRY304E (Sep 15, 2010)

oldtimer said:


> Please punctuate, and spell correctly, then, we may be able to help you!


 Do you have to give him a hard time about spelling..That is not going to help the guy..


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## oldtimer (Jun 10, 2010)

HARRY304E said:


> Do you have to give him a hard time about spelling..That is not going to help the guy..


 I think it will help the guy! I M O, his question will be easier to comprehend, if it is written properly.


What do you think fellow members?


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## don_resqcapt19 (Jul 18, 2010)

If each of the motors has its own start stop station, and you need to be able to run any two and prevent the other two from being started after you have started the first two, you will need a lot of relays. (but I am not sure exactly what the OP needs the control circuit to do).


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## Mike in Canada (Jun 27, 2010)

I'd use one intelligent relay and be done with it.


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## oliquir (Jan 13, 2011)

Mike in Canada said:


> I'd use one intelligent relay and be done with it.


me too they sell for about 100-150$ and will save you a lot of wiring and relays


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## Wirenuting (Sep 12, 2010)

Don't need any relays.. Just a couple of aux contacts for the contactors. 
They wire together similar to the way you would wire a 2 speed starter, but without the mechanical interlock.

http://ecatalog.squared.com/pubs/Machine Control/0140CT9201.pdf

Look thru this book.


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## The_Modifier (Oct 24, 2009)

Wirenuting said:


> http://ecatalog.squared.com/pubs/Machine Control/0140CT9201.pdf
> 
> Look thru this book.


Awesome suggestion. Now you can read up on the devices and options and I didn't have to order another catalog, lol.
Ty Wirenuting.:thumbsup:


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## don_resqcapt19 (Jul 18, 2010)

Wirenuting said:


> Don't need any relays.. Just a couple of aux contacts for the contactors.
> ...


How would you use a couple of aux contacts to permit any two, but only two of the 4 motors to run?


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## Wirenuting (Sep 12, 2010)

don_resqcapt19 said:


> How would you use a couple of aux contacts to permit any two, but only two of the 4 motors to run?


A similar way you do with a 2 speed starter. 
I can't give the answer because the OP is a student. But I think it's ok to give a good reference. That's why I posted the link to the Square D wiring diagram book.


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## don_resqcapt19 (Jul 18, 2010)

Wirenuting said:


> A similar way you do with a 2 speed starter.
> I can't give the answer because the OP is a student. But I think it's ok to give a good reference. That's why I posted the link to the Square D wiring diagram book.


I agree that it is a very good reference. I just don't agree that the required control sequence can be accomplished with a few aux contacts. This in not a simple "or" like you would have in a two speed motor.


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## Wirenuting (Sep 12, 2010)

don_resqcapt19 said:


> I agree that it is a very good reference. I just don't agree that the required control sequence can be accomplished with a few aux contacts. This in not a simple "or" like you would have in a two speed motor.


I'll agree that the easiest way would be to use a control relay of small plc. But it looks like the instructor said contacts. 
Be nice if the OP had more info. 
If I get the chance I'll draw it,, if I can,, and post it by weeks end. If I can't then I'll post a rugoldberg looking thing.
If you dazzle them with brilliance then baffle them with BS.


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## Hugo (Feb 21, 2011)

oldtimer said:


> Please punctuate, and spell correctly, then, we may be able to help you!


Sorry oldtimer i was on my droid phone and it some times it dose not recognize all the words correctly. 
Every one else thanks for all the help and ideas i will see if i can scan and place a picture of my drawing (if its even possible)or a link from my facebook or somthing thanks again.


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## Wirenuting (Sep 12, 2010)

Hugo said:


> Sorry oldtimer i was on my droid phone and it some times it dose not recognize all the words correctly.
> Every one else thanks for all the help and ideas i will see if i can scan and place a picture of my drawing (if its even possible)or a link from my facebook or somthing thanks again.


Are you allowed to use a small logic device? Or relays? Or must it be only with aux contacts? Can you draw a truth table for your desired operational state?


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## Hugo (Feb 21, 2011)

Wirenuting said:


> Don't need any relays.. Just a couple of aux contacts for the contactors.
> They wire together similar to the way you would wire a 2 speed starter, but without the mechanical interlock.
> 
> http://ecatalog.squared.com/pubs/Machine Control/0140CT9201.pdf
> ...


i just took a glance at it looks like it may help alot. going to take some more time to read thru it thanks


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## Hugo (Feb 21, 2011)

We are not allowed to use logic divices only ax contact.and I need about 6 contacts combo N.O and N.C with 4 contact relays I'll post a picture of my drawing later today


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## JRaef (Mar 23, 2009)

This looks an awful lot like a homework question now.

It can be done in theory, but you need more aux contacts on each contactor than any contactor I am aware of will allow. I counted 6NO and 12NC per contactor, plus you would need 4NO contacts on each Start PB. That was just a first pass at the logic, it may be able to be boiled down a bit but the most Aux. contacts I have ever seen available on a contactor is 8 total and I don't think it can be boiled down that far.

But here's a general logic hint for you.
Boil down each contactor circuit to a series of verbal questions, i.e. if this, if not this, and that, and not that, or that, or not that, will = energize. Then change the words from "if this", "and", "or" to NO, "if not this", "and not that", "or not that" to NC, then you have the ladder diagram.


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## JRaef (Mar 23, 2009)

Wirenuting said:


> Don't need any relays.. Just a couple of aux contacts for the contactors.
> They wire together similar to the way you would wire a 2 speed starter, but without the mechanical interlock.
> 
> http://ecatalog.squared.com/pubs/Machine Control/0140CT9201.pdf
> ...


The fact that they have 4 starters and only any 2 can be on at any time adds a level of complexity that doesn't translate to a simple 2S2W starter schematic.


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## Wirenuting (Sep 12, 2010)

JRaef said:


> The fact that they have 4 starters and only any 2 can be on at any time adds a level of complexity that doesn't translate to a simple 2S2W starter schematic.


The 2 speed was to give him an idea were to look. It is a home work question that's why I didn't post an answer for him. 
If you look at all his comments I think we can assume he might be close to the answer.


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## John (Jan 22, 2007)

There is a lot of logic involved and not a lot of information supplied. To many assumptions on our part. :whistling2:

View attachment 5883


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## Wirenuting (Sep 12, 2010)

John said:


> There is a lot of logic involved and not a lot of information supplied. To many assumptions on our part. :whistling2:
> 
> <img src="http://www.electriciantalk.com/attachment.php?attachmentid=5883"/>


Your right. I hope he posts it soon. I would like to compare what I drew this morning. 
Been awhile since I did it.


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## John (Jan 22, 2007)

Wirenuting said:


> Your right. I hope he posts it soon. I would like to compare what I drew this morning.
> Been awhile since I did it.


It would help if the original question was posted....*verbatim.:whistling2:*


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## don_resqcapt19 (Jul 18, 2010)

I think it can be done with 3 NC aux contacts on each starter and some non-conventional wiring of the start stop buttons.


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## Wirenuting (Sep 12, 2010)

don_resqcapt19 said:


> I think it can be done with 3 NC aux contacts on each starter and some non-conventional wiring of the start stop buttons.


Non-conventional wiring of the start / stop may cause a failure in his grade.


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## Hunter1151 (Nov 4, 2010)

All great advice, but first question I have is what determines what motors run and what don't. If motor 1 & 3 run, 2 & 4 off you can series your stops, then use a 3 position momentary selector, and interlock with N.C. Contacts in series of the other starter coils. If it is a random choice, then I am guessing there has to be a feedback to determine this, like a flow meter on a pump system, if flow is low another pump starts until flow rate is met, just as an example. I will gladly draw it and post, but I need to know the application. Without knowing and understanding the application it can not be drawn correctly.


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## Hugo (Feb 21, 2011)

ok "don" your 3 contacts NC is a good idea but i have already done that and dose not give desired affect. the project states. the following
to have" 4 start and stop stations to control 4 motors but only tow motors will run at a time.. the settings this would be used is as followed,
the plant has 4 motors but the grid being use by the plan allows only 2 motors to run at a time in one more motor is added to the grid it will blow an O.L. so i need to prevent the other 2 motors from running.
it can be any 2 motors
S1 S2 S3 S4 
M1 X X X OFF
M2 X OFF OFF X
M3 OFF X OFF X
M4 OFF OFF X OFF 
AND SO ON FOR EACH MOTOR


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## Hugo (Feb 21, 2011)

One drawing is how some one suggested using three N.C contacts, the one on the right
the one on the left is my unfinished drawing with 6 contacts per circuit. now I have tried to wire them up, but every time I do I keep getting one of my contacts getting in the way. seems o get really close to doing it but then a snag... O haven't drawn in the no/nc contacts or numberd them so you guys can't input your own.also I am a student but on the filed if you don't now the answer you get help, if I'm wrong for asking for help please tell me. every ones tips are helping "alot" thanks by the way we are not using PLC at the moment so its out of the question.


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## Hugo (Feb 21, 2011)

John said:


> There is a lot of logic involved and not a lot of information supplied. To many assumptions on our part. :whistling2:
> 
> View attachment 5883


this picture you places looks a lot like the process i need.. but again no plc is needed with this project only aux contacts.


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## Wirenuting (Sep 12, 2010)

Hugo said:


> ok "don" your 3 contacts NC is a good idea but i have already done that and dose not give desired affect. the project states. the following
> to have" 4 start and stop stations to control 4 motors but only tow motors will run at a time.. the settings this would be used is as followed,
> the plant has 4 motors but the grid being use by the plan allows only 2 motors to run at a time in one more motor is added to the grid it will blow an O.L. so i need to prevent the other 2 motors from running.
> it can be any 2 motors
> ...


Your close with your picture,, but as the contactor pulls in your switches will change state and the motor will drop out. 
You need a holding circuit & the other half of your aux contacts. 

When is this project due in class?


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## don_resqcapt19 (Jul 18, 2010)

My idea does only permit any two motors to run. There would be a possibility of a "relay race" on latching the second motor on, but with most starters I don't think this would be an issue as a result of the physical mass of the starter armature. It would likely be an issue with control relays, but I think it would work with the starters.


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## Wirenuting (Sep 12, 2010)

I always called this kind of control "Two Finger" control. You needed 2 fingers to press the buttons. It was a pain when you had to reach arms length in both directions just to get them going. 
Here is my truth table with binary 1 as n/o and binary 0 as n/c. 
I do not see a holding circuit on Hugo's one line. It also looks like he is energizing 2 coils with each start circuit.


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## Hunter1151 (Nov 4, 2010)

Use a custome cam switch for interlocking and ability and a standard 3 Wire start stop.


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## Wirenuting (Sep 12, 2010)

Hunter1151 said:


> Use a custome cam switch for interlocking and ability and a standard 3 Wire start stop.


He can't. It's school work, if you look at the pic he posted you can see were he wrote,, old time start stop. 
He said aux contacts only.


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## oliquir (Jan 13, 2011)

i know it is school work but i hope in future nobody will do that with aux contact , they should teach the right way to do it and avoid relay and aux contact and use a smart relay :whistling2:


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## Ghandiswrath (Nov 1, 2010)

Hugo, please ask yourself these questions.

#1. Do I want to trip the running motors if I start a non-running motor? (I think the answer to that is no)

#2. If the answer to 1 no, then shouldn't I hold in my entire circuit unless I push the stop or there is a motor malfunction?

#3. If I only want two motors running at any given time, and I don't want the motor to trip if I start a third motor (I only want it not to start) then my statement would be an "and, or" i.e. a parallel operation. 

You are very close with the way you have it. Good work so far! If you don't get it in the next few posts, I'll give you more of the answer.


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## Wirenuting (Sep 12, 2010)

oliquir said:


> i know it is school work but i hope in future nobody will do that with aux contact , they should teach the right way to do it and avoid relay and aux contact and use a smart relay :whistling2:


There are many right was of doing this. 
It's good that they are teaching the old way as there are still many old hard wired things out here. Not everyone has upgraded to the latest & greatest. Learning the basics makes it easier to step up to a problem and not be lost. He may never see anything like this again. But IMO he would be more valuable and less overwhelmed if he opened and old time master board covered in buttons and had an idea of what he sees.


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## Hugo (Feb 21, 2011)

Ghandiswrath said:


> Hugo, please ask yourself these questions.
> 
> #1. Do I want to trip the running motors if I start a non-running motor? (I think the answer to that is no)
> 
> ...


if i start motors one and 2 then the interlocking circuits aux contacts will make it impassable for motors 3 and 4 to turn on. if any part of motors 3 and 4 turn on there will be an over load in the plant and shut everything down. 
so what is needed is a prevention from more then to motors to run, before turning on a different motor you must 1st shut down a motor 1 or 2 to start motors 3 or 4.:thumbsup:


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## Hugo (Feb 21, 2011)

Wirenuting said:


> I always called this kind of control "Two Finger" control. You needed 2 fingers to press the buttons. It was a pain when you had to reach arms length in both directions just to get them going.
> Here is my truth table with binary 1 as n/o and binary 0 as n/c.
> I do not see a holding circuit on Hugo's one line. It also looks like he is energizing 2 coils with each start circuit.


wirenuting. is this the sequence of the contacts to be used? 
do i only need to add value to them? also the two "coils" you see in my drawing was from the previous project that called for interlocking all circuits.
i used 3 NC contacts with the values being
::station 3}{cr1 N.C }{cr2 N.C }{cr4 N.C then to coil or cr3


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## Wirenuting (Sep 12, 2010)

Hugo said:


> wirenuting. is this the sequence of the contacts to be used?
> do i only need to add value to them? also the two "coils" you see in my drawing was from the previous project that called for interlocking all circuits.
> i used 3 NC contacts with the values being
> ::station 3}{cr1 N.C }{cr2 N.C }{cr4 N.C then to coil or cr3


I wouldn't call it the sequence of operation. We just called it a truth table and added the a-1,a-2, a-3,,, ect as we drew it so we would have a numbering schedule when the time came to wire it up. 

When is the project due?


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## Ghandiswrath (Nov 1, 2010)

Hugo said:


> if i start motors one and 2 then the interlocking circuits aux contacts will make it impassable for motors 3 and 4 to turn on. if any part of motors 3 and 4 turn on there will be an over load in the plant and shut everything down.
> so what is needed is a prevention from more then to motors to run, before turning on a different motor you must 1st shut down a motor 1 or 2 to start motors 3 or 4.:thumbsup:


 That's correct, so if I use your control schematic I would shut a motor down if I start another motor up. This indicates that your holding circuit must be expanded to cover your aux relays.

Finally your Aux contacts are all making an "and" statement. Which means for M1 to run ~ M2, M3, and M4 must not be running. You must make a statement that reads for M1 to run, M2 and (M3 OR M4) must not be running. For M2 to run, M3, and (M4 OR M1) must not be running...etc.


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## don_resqcapt19 (Jul 18, 2010)

Wirenuting said:


> Non-conventional wiring of the start / stop may cause a failure in his grade.


 No code or operational violations...just not putting them in the circuit where you normally see them.


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## Wirenuting (Sep 12, 2010)

don_resqcapt19 said:


> No code or operational violations...just not putting them in the circuit where you normally see them.



I like creative ideas like that.


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## Hugo (Feb 21, 2011)

Ok 1st circuit gos:top line cr2/cr3/cr4 all n.c...bottom line cr1/cr2 n.o
2end line:top cr3/ca4\cr1n.o and3 and 4 are closed
bottom line is cr2/cr4 n.o


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## Wirenuting (Sep 12, 2010)

Hugo said:


> Ok 1st circuit gos:top line cr2/cr3/cr4 all n.c...bottom line cr1/cr2 n.o
> 2end line:top cr3/ca4\cr1n.o and3 and 4 are closed
> bottom line is cr2/cr4 n.o


Opps,, you drew a CR 1 and a motor coil. 

Just one load per line... C = coil on contactor.


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## don_resqcapt19 (Jul 18, 2010)

The use of 6 NC aux contacts per starter will let me do it with standard start/stop wiring and no risk of a relay race.


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## Hugo (Feb 21, 2011)

Ok ov been working and reading and it can can be done with only 4 contacts give me to tonight to figuer it out and I'll post the drawing


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## Ghandiswrath (Nov 1, 2010)

Hugo said:


> Ok ov been working and reading and it can can be done with only 4 contacts give me to tonight to figuer it out and I'll post the drawing


 THat's correct!


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## JRaef (Mar 23, 2009)

An issue not addressed in the OP and some of the above is this.
Does it need to cover ANY sequence of starting the 4 motors, or will it always be the same sequence.


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## Hugo (Feb 21, 2011)

Here is the drawing this of the drawing more I just need to put them in the correct order


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## Hugo (Feb 21, 2011)

Here if the drawing.


The operating or sequence need ed is any two motors running any two in any sequence


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## Wirenuting (Sep 12, 2010)

On your drawing you show a CR and a motor connected to your start circuit. 
I assumed you could only use mechanical aux contacts. 
Here are 2 pictures showing a pair of mechanical aux contacts mounted on a starter. These are single pole but you can get single pole double throw also. 
Each motor starter needs at least one unbroken path for power to the starter coil. 
Here is an example. Remember the drawing is de-energized and will change state when you push the start button.


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## don_resqcapt19 (Jul 18, 2010)

Hugo said:


> Ok ov been working and reading and it can can be done with only 4 contacts give me to tonight to figuer it out and I'll post the drawing


 Just 4 contacts, or 4 contacts per starter?


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## Hugo (Feb 21, 2011)

don_resqcapt19 said:


> Just 4 contacts, or 4 contacts per starter?


Yes don I'm working on what the order of the contact s are going to be right now
NOTE: the circuit works with only 4 contacts used so no additional contact coils are needed 
so i can use only 1 N.O holding contact and 3 N.O contacts from a different CR to get interlocking from other 2 motors.


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## Hugo (Feb 21, 2011)

This is my setup that I'm using the list is the list from left tio right: push buttons 4 station mid 4 contacters then 4 light acting as motors 2 terminals strip s


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## Ghandiswrath (Nov 1, 2010)

Hugo said:


> Here if the drawing.
> 
> 
> The operating or sequence need ed is any two motors running any two in any sequence


 Very good, but you need to make three changes. 

#1. All of your aux contacts need to be NC.

#2. You need to label your Aux contacts by their CR. 

#3. Your Holding circuit is still in the wrong spot.


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## Mike in Canada (Jun 27, 2010)

To me, the 'proper' way to solve this is with 3 NC auxilliaries on each contactor, plus one NO to act as the holding contact.

The push button for 'A' is powered through:
(not B and not C) or (not B and not D) or (not C and not D)

Each push-button is similarly wired. This allows them to start in any order, and doesn't mess up the already-running motors. It's just checking to make sure that two motors are off before you can start a motor.

A terminal strip is the way to go for this... much cleaner.


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## don_resqcapt19 (Jul 18, 2010)

Mike in Canada said:


> To me, the 'proper' way to solve this is with 3 NC auxilliaries on each contactor, plus one NO to act as the holding contact.
> 
> The push button for 'A' is powered through:
> (not B and not C) or (not B and not D) or (not C and not D)
> ...


That would require 6 NC on each starter, not 3. You used two of each of motors other than A for the first motor. That will be the same for each of the other 3 motors, requiring 24 contacts.


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## hardworkingstiff (Jan 22, 2007)

I would take a completely different approach. 

A normally wired start circuit that will feed the common of 2 on/on selector switches which then feed to the motor starter coils. The stop would drop out the holding circuit to the coils.

Selector switches would only allow you to pick 2 motors at a time.


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## Hugo (Feb 21, 2011)

Ghandiswrath said:


> Very good, but you need to make three changes.
> 
> #1. All of your aux contacts need to be NC.
> 
> ...


#1. yes i was going through the drawing and figuerout that thayneed to be closed.
#2. right now im working on that. right now i got
M1 AND M2,M3,M4, running ok buy when i get to M2 and M3 i dont get interlock in M1 and M4 

#3 my holding contact is below my start button.


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## Mike in Canada (Jun 27, 2010)

don_resqcapt19 said:


> That would require 6 NC on each starter, not 3. You used two of each of motors other than A for the first motor. That will be the same for each of the other 3 motors, requiring 24 contacts.


 You don't need to duplicate them. Both C and D require "not A and not B", but you can use the same feed. The possible combinations are:

not A and not B
not A and not C
not A and not D
not B and not C
not B and not D
not C and not D

Each logical 'statement' is landed in a terminal strip.
Each motor needs to 'or' a couple of these together, but they needn't be 'dedicated'. You can connect three motors to the same logic. As you can see, in the list above there are three A's, three B's, three C's and three D's. Hence three NCs per contactor - one for each logical 'statement' that it is a part of.


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## Hugo (Feb 21, 2011)

Mike in Canada said:


> You don't need to duplicate them. Both C and D require "not A and not B", but you can use the same feed. The possible combinations are:
> 
> not A and not B
> not A and not C
> ...


we are not using logic only contacts check out my layout on pg 3 thats the bored im using..


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## Ray Cyr (Nov 21, 2007)

Hugo said:


> This is my setup that I'm using the list is the list from left tio right: push buttons 4 station mid 4 contacters then 4 light acting as motors 2 terminals strip s


In your pic, the contactors in the middle, How many sets of n.o. and n.c. contacts do you have on each contactor?


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## Hugo (Feb 21, 2011)

Ray Cyr said:


> In your pic, the contactors in the middle, How many sets of n.o. and n.c. contacts do you have on each contactor?


there is 4 contacts thai can be changed tio no or nc


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## Ray Cyr (Nov 21, 2007)

Hugo said:


> there is 4 contacts thai can be changed tio no or nc


Well, I hope someone posts a solution for the set up that you have because my tired brain is not seeing one :surrender: :laughing:


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## Jlarson (Jun 28, 2009)

I think I see where Mike is going with his idea, although I have to draw it out and play with it myself to see what it would do.


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## JRaef (Mar 23, 2009)

LOL, I drew it out on a piece of graph paper yesterday. I just realized I used the other side of that sheet to explain another circuit to someone today and left it with him. If he flips it over, he is going to be VERY confused!


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## Hugo (Feb 21, 2011)

JRaef said:


> LOL, I drew it out on a piece of graph paper yesterday. I just realized I used the other side of that sheet to explain another circuit to someone today and left it with him. If he flips it over, he is going to be VERY confused!


Lol well I been working on this for two weeks on friday and I'm a bit e warn out so inga hit the hay thanks guys I all most got it maybe tomorrow


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## JRaef (Mar 23, 2009)

Two valid start conditions: 
Condition 1 = Start with nothing on, 
Condition 2 = Start with only one other on.

So in addition to the standard 3 wire S/S for each circuit (1NO per starter):

Motor A, Cond. 1 = Not B, and Not C, and Not D (1NC per other), OR
Motor A, Cond. 2 = 
B and Not C and Not D, OR
C and Not B and Not D, OR
D and Not B and Not C
(1NO per other, plus 2NC per other)

Seal-in from the S/S circuit goes around all of this.

Repeat for each starter. Each starter will need 3NC per circuit except its own and 1 NO per circuit, = 4NO and 9NC per starter.


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## Mike in Canada (Jun 27, 2010)

JRaef said:


> Two valid start conditions:
> Condition 1 = Start with nothing on,
> Condition 2 = Start with only one other on.


 I found it much simpler to just say "start only if there are two motors that are off". That way, there can be two, three, or four motors off, and it all works, and the logic is more elegant. 1NO and 3NC per starter.


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## Mike in Canada (Jun 27, 2010)

hardworkingstiff said:


> I would take a completely different approach.
> 
> A normally wired start circuit that will feed the common of 2 on/on selector switches which then feed to the motor starter coils. The stop would drop out the holding circuit to the coils.
> 
> Selector switches would only allow you to pick 2 motors at a time.


 How would you start the two motors on one switch?


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## hardworkingstiff (Jan 22, 2007)

Mike in Canada said:


> How would you start the two motors on one switch?


You couldn't.

From the OP, I didn't think that was an issue.


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## Mike in Canada (Jun 27, 2010)

Hugo said:


> we are not using logic only contacts check out my layout on pg 3 thats the bored im using..


 We're not using logic. Only contacts.

Wow. 

Someday you're going to look back at that statement and really smack yourself in the forehead.

I saw the pictures of the 'bored' you're using, and as long as you have one NO and three NC aux. contacts per starter then you can use the method that I laid out, and it will work elegantly without a godawful mess of wiring. Or, you can continue beating your head against the problem. You said you were three weeks into it, was it? Maybe it's time that you thought a bit harder about whether logic is required to solve the problem.


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## HARRY304E (Sep 15, 2010)

hardworkingstiff said:


> You couldn't.
> 
> From the OP, I didn't think that was an issue.


What!?:laughing:

Unless it is prohibited by Artical 430.or elswhere in the NEC..You can control as many motors from one switch as you want.

You can have a motor control cabinet with all you're motor starters controled by one start stop button...Right?:blink:


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## hardworkingstiff (Jan 22, 2007)

Hugo said:


> draw a schematic for a 4 stop and start P.B. stations to control 4 motors with interlock and any two motors running at anytime with the other 2 to remain off





Hugo said:


> to have" 4 start and stop stations to control 4 motors but only tow motors will run at a time.. the settings this would be used is as followed,
> the plant has 4 motors but the grid being use by the plan allows only 2 motors to run at a time in one more motor is added to the grid it will blow an O.L. so i need to prevent the other 2 motors from running.





HARRY304E said:


> Unless it is prohibited by Artical 430.or elswhere in the NEC..You can control as many motors from one switch as you want.
> 
> You can have a motor control cabinet with all you're motor starters controled by one start stop button...


Harry, once again I don't understand why you posted what you posted.

My solution was attempting to meet the requirements of the OP. He definitely wanted to PROHIBIT 2 motors from running.


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## hardworkingstiff (Jan 22, 2007)

A written sequence of operation would be helpful.

Do you need the option of picking any combination of motors or is it normally one pair or the other?

Do you need to automatically switch to a different motor if a selected motor fails to start or fails during the operation?


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## hardworkingstiff (Jan 22, 2007)

HARRY304E said:


> What!?:laughing:
> 
> Unless it is prohibited by Artical 430.or elswhere in the NEC..You can control as many motors from one switch as you want.
> 
> You can have a motor control cabinet with all you're motor starters controled by one start stop button...Right?:blink:


You do understand the switch Mike and I were referring to was the selector switch not the start switch, right?


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## HARRY304E (Sep 15, 2010)

Mike in Canada said:


> How would you start the two motors on one switch?





hardworkingstiff said:


> You couldn't.
> 
> From the OP, I didn't think that was an issue.


I was simply responding to the two post above...Not to the OP..sorry


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## hardworkingstiff (Jan 22, 2007)

HARRY304E said:


> I was simply responding to the two post above...Not to the OP..sorry


The posts you were responding to were talking about the selector switch, not the start switch.


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## don_resqcapt19 (Jul 18, 2010)

Mike in Canada said:


> You don't need to duplicate them. Both C and D require "not A and not B", but you can use the same feed. The possible combinations are:
> 
> not A and not B
> not A and not C
> ...


If you are putting that logic sequence on the line side of the start buttons, where are you connecting the power for the seal in contact?


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## HARRY304E (Sep 15, 2010)

hardworkingstiff said:


> The posts you were responding to were talking about the selector switch, not the start switch.


Yes i know..:whistling2:


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## Wirenuting (Sep 12, 2010)

Hugo,

I understand this is a class room practical and I reminds me of a 5 motor car wash we did 25 years ago in class. 

But can you tell me a few things,
Can you start it all by pressing 2 start buttons?
Do you have to stop a motor before starting the next?
Can you use the relay seen in your picture?
Can you use starter mounted aux contacts?

Can you press 2 start buttons to begin and then press only the 3rd start button and allow a motor to drop out?


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## JRaef (Mar 23, 2009)

Mike in Canada said:


> I found it much simpler to just say "start only if there are two motors that are off". That way, there can be two, three, or four motors off, and it all works, and the logic is more elegant. 1NO and 3NC per starter.


Damn, you're absolutely right. I thought it could be boiled down further, I was just too tired to see it last night. Sometimes I tend to jump in with a solution that works and have to stare at a ladder for a while to see what redundancies I can eliminate.


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## Ghandiswrath (Nov 1, 2010)

This is the proper solution. Uses the least amount of Aux contacts and is will allow the start in any sequense. The only reason I post this is you're getting mixed results here on the forum, and you were very close already.


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## Hugo (Feb 21, 2011)

Ghandiswrath said:


> This is the proper solution. Uses the least amount of Aux contacts and is will allow the start in any sequense. The only reason I post this is you're getting mixed results here on the forum, and you were very close already.


how would you prevent station 3 and 4 from turning on is station 1, and 2, are running? if my holding circuit is bypassing my 3 contacts from different CRs then it would not be interlock, right?:001_huh:


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## Ghandiswrath (Nov 1, 2010)

Hugo said:


> how would you prevent station 3 and 4 from turning on is station 1, and 2, are running? if my holding circuit is bypassing my 3 contacts from different CRs then it would not be interlock, right?:001_huh:


 You are preventing the start, not tripping another started motor. In that scenario, when you start motor one, you hold motor one with it's own contact. You would also open any NC contact associated with M1. Note that it removes any "OR" statement in your control scheme. If you start any other motor in the scheme, it would then remove all other "AND" statements in your scheme thus preventing a start. :thumbsup:


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## Hugo (Feb 21, 2011)

Wirenuting said:


> Hugo,
> 
> I understand this is a class room practical and I reminds me of a 5 motor car wash we did 25 years ago in class.
> 
> ...


no here is what the project requires.
"draw a schematic for 4 stop and start P.B stations to control 4 motors with interlock with any two motors to start at anytime, but not the other two":whistling2:
now i got my drawing ready but i need to move the contacts around so i get the interl lock when i start M2 and M3 ill posting my drawing in a few mins


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## Hugo (Feb 21, 2011)

Ghandiswrath said:


> You are preventing the start, not tripping another started motor. In that scenario, when you start motor one, you hold motor one with it's own contact. You would also open any NC contact associated with M1. Note that it removes any "OR" statement in your control scheme. If you start any other motor in the scheme, it would then remove all other "AND" statements in your scheme thus preventing a start. :thumbsup:


in your drawing if i start station's 1 and 2, it could be possible to start station 3 and 4 that being you can bypass by going through n.c contact from cr3:001_huh:


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## don_resqcapt19 (Jul 18, 2010)

Ghandiswrath said:


> This is the proper solution. Uses the least amount of Aux contacts and is will allow the start in any sequense. The only reason I post this is you're getting mixed results here on the forum, and you were very close already.


 In your drawing, if #2 and #3 are running you can still start #1.


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## Hugo (Feb 21, 2011)

ok here is my drawing this works cuzz its my next project.. now i need this to run any 2 stations and not the other two. i cant use logic controls or relays as it will work with out them. 
im thinking about inter locking stations 1 and 2...' 3 and 4 with P.B interlocking but i dont know if it will work yet


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## Ghandiswrath (Nov 1, 2010)

Hugo said:


> in your drawing if i start station's 1 and 2, it could be possible to start station 3 and 4 that being you can bypass by going through n.c contact from cr3:001_huh:


 sorry, still wrong.


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## hardworkingstiff (Jan 22, 2007)

never mind


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## Ghandiswrath (Nov 1, 2010)

:jester:


JRaef said:


> Two valid start conditions:
> Condition 1 = Start with nothing on,
> Condition 2 = Start with only one other on.
> 
> ...


This is the correct method. I overlooked a sequence. :wallbash:


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## hardworkingstiff (Jan 22, 2007)

How about this way? Any motor coming on drops out 2 paths and if either of the other 2 motors comes on the 2nd path is dropped. Just change the CR labels for each set of motors.

I give up, I just don't have a handle on posting pictures.


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## Hugo (Feb 21, 2011)

Ghandiswrath said:


> sorry, still wrong.


I'm wrong or your wrong?


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## Del (Feb 10, 2011)

*Logic issue*

One approach I would use,

Do a normal starter cct, with a extra contact in the start p.b line.

Then do a logic 'and gate type' cct on the side to monitor the number of running coils, and open the contact in the other starters when it hits a 2 count.

The hard work is in latching the 'and' inputs to keep the 2 running starters going and not switching off the 2 you want.


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## JRaef (Mar 23, 2009)

Ghandiswrath said:


> :jester:This is the correct method. I overlooked a sequence. :wallbash:


Actually, Mike in Canada's condensation of this is the best way. Eliminate the firs rung (with 3 NC), eliminate the NO isolation contacts in the other rungs as unnecessary without it. 

A = Not B&C, or Not B&D, or Not C&D, seal in for A around Start.

B = Not A&C, or Not A&D, or Not C&D, seal in for B around Start.

C = Not B&A, or Not B&D, or Not A&D, seal in for C around Start.

D = Not B&C, or Not B&A, or Not C&A, seal in for D around Start.

If I get a chance later I'll redo that drawing with his change.


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## Ghandiswrath (Nov 1, 2010)

JRaef said:


> Actually, Mike in Canada's condensation of this is the best way. Eliminate the firs rung (with 3 NC), eliminate the NO isolation contacts in the other rungs as unnecessary without it.
> 
> A = Not B&C, or Not B&D, or Not C&D, seal in for A around Start.
> 
> ...


 Agreed.


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## Mike in Canada (Jun 27, 2010)

don_resqcapt19 said:


> If you are putting that logic sequence on the line side of the start buttons, where are you connecting the power for the seal in contact?


 You can get that power anywhere you want, as long as it's a clean source. The logic just 'gets the ball rolling'. The holding contact can be powered by anything.


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## Mike in Canada (Jun 27, 2010)

Ghandiswrath said:


> Agreed.


 Other than the push-buttons (I think you grabbed the wrong ones, there) it looks great! Although, to be fair, I had referred previously to using the logic to power the 'on' button, rather than have the logic after the push-buttons.


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## JRaef (Mar 23, 2009)

Ghandiswrath said:


> Agreed.


There it is, other than the button symbols.


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## JRaef (Mar 23, 2009)

Mike in Canada said:


> You can get that power anywhere you want, as long as it's a clean source. The logic just 'gets the ball rolling'. The holding contact can be powered by anything.


No, the holding contact has to be powered down stream of the Stop button, otherwise you can't turn it off. 

Unless you put the Stop button as the last element ahead of the coil, which is let's just say... _unconventional_.

From the old JIC Wiring Standards book, still taught to industrial electricians:
*Symbol used in motor control relay circuits **JIC-NMTBA








*Not in ladder format, but the point is that the circuit begins at the Stop button.

The nice thing about using conventional / familiar circuit designs is that when someone walks up to it in a hurry and ASS-U-Mes it is wired the way every other one he has seen is, it's nice to not cause extra chances of error. Sure, he shouldn't Ass-U-Me, but in reality, every one does at first glance.


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## don_resqcapt19 (Jul 18, 2010)

This one has a possible issue with a relay race between the opening of the NC contact and the closing of the NO contact when starting the second motor.
And yes it does have an unconventional placement of the stop button.


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## JRaef (Mar 23, 2009)

don_resqcapt19 said:


> This one has a possible issue with a relay race between the opening of the NC contact and the closing of the NO contact when starting the second motor.
> And yes it does have an unconventional placement of the stop button.


Which one was that Don? Looks like it dropped off of whatever server you linked to.


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## don_resqcapt19 (Jul 18, 2010)

http://s561.photobucket.com/albums/ss53/resqcapt19/4motors/


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## Wirenuting (Sep 12, 2010)

don_resqcapt19 said:


> http://s561.photobucket.com/albums/ss53/resqcapt19/4motors/


I do like your unconventional wiring like you mentioned the other day. But wouldn't you need to repeat your first line for the other starters? And if any 2 OR's were open then that motor is stopped. Wouldn't each OR set need 3 n/c ?

It looks like once the first coil energized you wouldn't be able to start a second. It's hard to see your pic on my screen. 

Also I can't remember were I read it, but it goes back to when they wanted us to fuze the start circuit. I seem to remember that the stop button must be placed first due to a short being able to energize the coil else were. But I can't recall.


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## Jlarson (Jun 28, 2009)

Ghandiswrath said:


> Agreed.


That's what I came up with, your drawing is nicer though, I worked it out on a napkin this morning :laughing:


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## don_resqcapt19 (Jul 18, 2010)

The top line of my drawing has six pairs of NC contacts. These 6 pairs are all of the possible combinations of two motors already running. If both of the contacts of any pair are open you can't start the third motor. The idea is really the same as the pairs in series with each other in the drawing in the post just before this one.
I did another one using the same concept of "pairs" but using 3 sets for each motor circuit and, just like the drawing above, that eliminates the seal in issue. 
I was just trying to use the very minimum of aux contacts, but I think that the least number you can use is 6 NC and 1 NO per starter to comply with the requirements.
The seal in contact goes around all of the pairs so assuming that there is enough physical mass on the starter armature the NO seal in contact will close soon enough to keep the armature pulled in. I expect that this issue would be a problem if our student used this circuit. I don't think there is a circuit that only uses 3 NC contact on each starter that will not have this problem.


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## don_resqcapt19 (Jul 18, 2010)

The six pairs in the top line of my drawing are: 1) M1 & M2, 2) M3 & M4, 3) M2 & M3, 4) M1 & M4, 5) M1 and M3, and 6) M2 & M4.
As long as there is not two motors running the circuit will supply power to the start buttons.


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## Hugo (Feb 21, 2011)

Jlarson said:


> That's what I came up with, your drawing is nicer though, I worked it out on a napkin this morning :laughing:


in this drawing you can still turn on station 3 and 4 you have no cr1 contacts interlocking them from starting ill try to work it out thanks


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## Ray Cyr (Nov 21, 2007)

don_resqcapt19 said:


> http://s561.photobucket.com/albums/ss53/resqcapt19/4motors/


NICE 
Yes it is unconventional, but it definitely works.
Today is a good day, I learned something today
Thank you Don :thumbup:

The only small problem that I see is that you are not showing the control relays in parallel to the starter coil.


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## Jlarson (Jun 28, 2009)

Hugo said:


> in this drawing you can still turn on station 3 and 4 you have no cr1 contacts interlocking them from starting ill try to work it out thanks


:laughing: I didn't notice that, I didn't notice he used the wrong PB symbols either, I looked at it quick on my way out the door to a call. I'd scan my version for you but I don't think the office would be too happy if I tried to run a napkin threw the scanner. 


I really like Don's though now, it's different and I like different.


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## hardworkingstiff (Jan 22, 2007)

Hugo said:


> in this drawing you can still turn on station 3 and 4 you have no cr1 contacts interlocking them from starting ill try to work it out thanks


Yea, he just mis-labeled them.


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## Jlarson (Jun 28, 2009)

hardworkingstiff said:


> Yea, he just mis-labeled them.


That's what happens when you get careless with copy and paste. :laughing:

I do that all the time while drawing prints, I catch it, most of the time :whistling2:


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## Hugo (Feb 21, 2011)

man been working on this tell me what you guys think please i think i got it!:thumbup:


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## Hugo (Feb 21, 2011)

Jlarson said:


> That's what I came up with, your drawing is nicer though, I worked it out on a napkin this morning :laughing:


i fixed it i think it works good but i was told by my instructor i could do this project with only 4 contacts.


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## Ray Cyr (Nov 21, 2007)

Hugo said:


> man been working on this tell me what you guys think please i think i got it!:thumbup:


Sorry to tell you but if motor 4 is on, none of the others can be turned on...


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## Jlarson (Jun 28, 2009)

Hugo said:


> i fixed it i think it works good but i was told by my instructor i could do this project with only 4 contacts.


4 contacts total or 4 contacts on each starter?


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## Hugo (Feb 21, 2011)

Jlarson said:


> 4 contacts total or 4 contacts on each starter?


arrg...your right I'm so tiered I think I'll give it one more go


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## Jlarson (Jun 28, 2009)

What are you using as control relays?


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## Hugo (Feb 21, 2011)

Jlarson said:


> What are you using as control relays?


there called contact relays they look a bit like a mag starter


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## Jlarson (Jun 28, 2009)

Hugo said:


> there called contact relays they look a bit like a mag starter


Ok looking back at your project board I see 4 NEMA style control relays but no contactors or starters what's the deal there?


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## Hugo (Feb 21, 2011)

Jlarson said:


> Ok looking back at your project board I see 4 NEMA style control relays but no contactors or starters what's the deal there?


the black thing in the middle is my contactor it has 4 contacts on top we use it as are starter so in fact its like a relay for us as well. i did not use cube relays 
my motors in the bored are my lights then on other side i have my PB stations 4 and 4 with a selector switch and Estop
we use one of the contacts on the relay to make a holding circuit then use other 3 for what ever we need like interlocking and stuff


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## Jlarson (Jun 28, 2009)

Ok so you are putting the lights in parallel with the CR coils to simulate the motors. 

As long as each relay has 3 NC and 1 NO contact you should be able to do it.


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## Hugo (Feb 21, 2011)

Jlarson said:


> Ok so you are putting the lights in parallel with the CR coils to simulate the motors.
> 
> As long as each relay has 3 NC and 1 NO contact you should be able to do it.


well iv try'ed very hard to do it with only 3 N/C and 1 N/O but its really hard to do that the only way i can see to do that is by 1,no and 6nc per station but my instructor says 1 no and 4 nc will do it


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## hardworkingstiff (Jan 22, 2007)

*less contacts*

Removed, it didn't work.


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## don_resqcapt19 (Jul 18, 2010)

Ray Cyr said:


> NICE
> Yes it is unconventional, but it definitely works.
> Today is a good day, I learned something today
> Thank you Don :thumbup:
> ...


I am not using any control relays. The contacts are all auxiliary contacts on the starters.


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## Ray Cyr (Nov 21, 2007)

don_resqcapt19 said:


> I am not using any control relays. The contacts are all auxiliary contacts on the starters.


Ah, I see 
I thought you were using only items in the picture that the OP posted of the things that he has to use for this project.


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## don_resqcapt19 (Jul 18, 2010)

Ray Cyr said:


> Ah, I see
> I thought you were using only items in the picture that the OP posted of the things that he has to use for this project.


 Ray,
The rules of what we can use and what the required sequence of operation is seem to be changing as the thread moves along.
I am almost sure that my circuit would not work with control relays, and it is "iffy" if it will work with motor starters.

I can't come up with a way to use only 3 NC and 1 NO contacts for each starter that won't have the "relay race" issue that my circuit has. 

I can build one that will work for sure and permit the operation of any two and only two motors at a time, but I need to use 6 NC and 1 NO per starter.


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## don_resqcapt19 (Jul 18, 2010)

Jlarson said:


> ...
> As long as each relay has 3 NC and 1 NO contact you should be able to do it.


 You have a circuit that uses only those contacts and permits you to start two and only two motors in any sequence and the circuit does not have the possibility of a "relay race" issue?


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## Jlarson (Jun 28, 2009)

don_resqcapt19 said:


> You have a circuit that uses only those contacts and permits you to start two and only two motors in any sequence and the circuit does not have the possibility of a "relay race" issue?


No, now that I know what relays he's using it I doubt it will work reliably. I even played with some scrap components today. Just like you the only reliable way I can find to do this is the 6 NC and 1 NO/relay way.


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## Hugo (Feb 21, 2011)

I presented my drawing with 6nc contact s and he asked "you did not use 3 contacts? You could not do it? well give it I shot"he look a bit disappointed as the class has 3 groups advanced, intermedeit,beginer and my team is in the beginer and we are the only team that caught up to the advanced class


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## Wirenuting (Sep 12, 2010)

Hugo said:


> I presented my drawing with 6nc contact s and he asked "you did not use 3 contacts? You could not do it? well give it I shot"he look a bit disappointed as the class has 3 groups advanced, intermedeit,beginer and my team is in the beginer and we are the only team that caught up to the advanced class


Did you mention the help you had? 

Oh and is one of your partners named Tornado on a different site? The same question was posted there for a logic answer.


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## Hugo (Feb 21, 2011)

Wirenuting said:


> Did you mention the help you had?
> 
> Oh and is one of your partners named Tornado on a different site? The same question was posted there for a logic answer.


yes i did and i dont know who that is maybe some one in a different class
but we are still wiring it had to borrow 4 more CRs also the advanced guys started the same project as we did... they waited for some one to come up with a drawing and just spy-ed there drawing too i guess its funny how after some one els presents a drawing that they also have it  
what site was this?


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## Hugo (Feb 21, 2011)

Ok I did the project today and I uploaded it to my youtube channel look up hugo1221 I will be thanking some people on there as soon as I get home


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## Wirenuting (Sep 12, 2010)

Hugo said:


> Ok I did the project today and I uploaded it to my youtube channel look up hugo1221 I will be thanking some people on there as soon as I get home


The site is CR4.globalspec.com
It's a control forum website. 
Glad your project worked out. 
Slap your YouTube link here so we can be lazy and watch it.


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## BBQ (Nov 16, 2010)

Hugo said:


> Ok I did the project today and I uploaded it to my youtube channel look up hugo1221 I will be thanking some people on there as soon as I get home


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## don_resqcapt19 (Jul 18, 2010)

So how many contacts did you use to make it work?


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## Hugo (Feb 21, 2011)

don_resqcapt19 said:


> So how many contacts did you use to make it work?


26 CONTACTS IN TOTAL. HERES THE LINK GUYS http://www.youtube.com/watch?v=hFnlsBB4X2U


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## Wirenuting (Sep 12, 2010)

Hugo said:


> 26 CONTACTS IN TOTAL. HERES THE LINK GUYS http://www.youtube.com/watch?v=hFnlsBB4X2U


Nice job. 
Can you take a shot of your diagram?
It looks like you used relays for controlling the starters.


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## Hugo (Feb 21, 2011)

Wirenuting said:


> Nice job.
> Can you take a shot of your diagram?
> It looks like you used relays for controlling the starters.


ya we used 6 contact relays and 2 cube relays:blink:


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