# Motor Control Course



## JRaef (Mar 23, 2009)

EB Electric said:


> Well I have just over a week before I start my apprenticeship, getting really excited! Thought I'd share a drawing from my motor controls course back from a few weeks into the course. Nothing fancy to brag about, but everyone has to start somewhere. We wired up the control circuit to a 3 phase 208 power circuit supplying a 1/3hp motor and then created the cad drawing.
> 
> Control ct 1 is for a simple combined start-stop-jog station using start-stop switch and selector switch. Switch in jog position the start button jogs the motor, switch in run position allows motor starter to seal in and continuous run of the motor.
> 
> ...


Not bad, I know how you feel, I remember when I first started doing controls, I thought is was cool. Still do, 30 years later...

Ckt 2, your Jog button is going to work exactly the same as the Start button, it will seal in. I know what you did wrong, lets see if you can fix it.


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## EB Electric (Feb 8, 2013)

Very cool stuff, we have done some basic plc's now also, quite neat! I really enjoy it. As for ckt 2, I am not sure what is wrong. I should have maybe mentioned the jog button was made by using only the start button on a separate start-stop device. We ran the motor with jog button and it operated properly, did not seal in the motor starter. Just tracing through the circuit: jog button is pressed, the motor starter coil is energized, out through overload, to neutral. complete circuit. The N.O. motor starter contact would close but it would not have power because the N.O control relay contact would be open preventing any current from flowing. The only way the starter could seal in is if the CR coil is energized, which there is no path unless start is pushed. Not meaning to be belligerent or anything.


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## Rochsolid (Aug 9, 2012)

I don't think you need that NO CR holding contact in series with your M holding contact.


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## dronai (Apr 11, 2011)

What software are you using?


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## EB Electric (Feb 8, 2013)

Rochsolid said:


> I don't think you need that NO CR holding contact in series with your M holding contact.


Without the NO CR on line 3 the motor starter would seal in when the jog button is pushed and the jog function will be lost, it would act as another run. I believe the NO CR on line 3 is correct.


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## EB Electric (Feb 8, 2013)

dronai said:


> What software are you using?


I am using AutoCAD 2012. I don't own it, it's provided by the college. It seems to work pretty well for what we have been doing.


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## dronai (Apr 11, 2011)

Why do the numbers for the O/L's jump up to 95, 96 ?


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## EB Electric (Feb 8, 2013)

dronai said:


> Why do the numbers for the O/L's jump up to 95, 96 ?


They are 95, 96 because these are the numbers on the NC O/L terminal that we were provided with. From what I was taught by the instructors 95, 96 is the industry standard for a NC thermal overload. It is an Allen Bradley if that makes any difference.


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## dronai (Apr 11, 2011)

Someone on here (ET) actually taught me some what on drawing schematics, I didn't know that about the O/l's typical.


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## micromind (Aug 11, 2007)

dronai said:


> Why do the numbers for the O/L's jump up to 95, 96 ?


Most IEC starters use 95/96 as the NC on the O/L relay.


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## JRaef (Mar 23, 2009)

EB Electric said:


> Without the NO CR on line 3 the motor starter would seal in when the jog button is pushed and the jog function will be lost, it would act as another run. I believe the NO CR on line 3 is correct.


D'oh! You are right, my apology! It's just a little more complicated than it needs to be for me. I would have just put The Jog button NO in parallel with the Start like you have it, but use a NC on the same button in series with the M seal-in contact. No relay necessary. But now I see your point about this being useful if you want MULTIPLE Jog buttons, because with the relay, you don't need to run all of those NC contact wires.

Nice job.


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## JRaef (Mar 23, 2009)

micromind said:


> Most IEC starters use 95/96 as the NC on the O/L relay.


In IEC equipment, every terminal has to be numbered, and each set of numbers has a very SPECIFIC (rationalized) meaning. For example you may have noticed that on aux contacts or relay contacts, the first NO contact is labeled 13/14, then the second NO contact is 23/24. If the second aux is NC, they are 21/22. That first digit is the POSITION of the contact, starting closest to the coil, left to right, the second number is the ACTION of the contact in relation to the "Normal" state of the device, defined as not energized, not tripped. 1/2 = Closed when Off, 3/4 = Open when Off, etc. etc. So 13/14 means bottom deck of contacts, first on the left, NO status when the coil is de-energized. For an OL relay, 95/96 = Closed when not tripped, opens on tripping, 97/98. = Open when not tripped, closes when tripped.

For years, NEMA motor starters had no terminal number markings on the OL aux contact, it was just called "OL" and everyone knew how it was supposed to be wired. in fact it came pre-wired from the factory. Aux contacts on contactors and relays were just labeled as NO or NC, then A, B, C or 1,2,3 etc for the first, second and third. But when IEC starters began showing up in North America in the 70s, they had these other numbers embedded in the moldings, so engineers started seeing them and using them. After a while, NEMA mfrs who wanted to sell their products in other parts of the world had to add those numbers to conform to IEC requirements, now it has become the defacto standard.


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## EB Electric (Feb 8, 2013)

JRaef said:


> D'oh! You are right, my apology! It's just a little more complicated than it needs to be for me. I would have just put The Jog button NO in parallel with the Start like you have it, but use a NC on the same button in series with the M seal-in contact. No relay necessary. But now I see your point about this being useful if you want MULTIPLE Jog buttons, because with the relay, you don't need to run all of those NC contact wires.
> 
> Nice job.


No worries. You had me tracing it through double checking, great practice for a new guy like me. :thumbsup: Yeah you're right, for the single jog the relay is over doing it really, but for multiple saves some wire. Thanks. I'll see about posting some more of the circuits from the course if anyone is enjoying these?


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## Rochsolid (Aug 9, 2012)

EB Electric said:


> Without the NO CR on line 3 the motor starter would seal in when the jog button is pushed and the jog function will be lost, it would act as another run. I believe the NO CR on line 3 is correct.


I don't see a need for either of those contacts by your jog button, unless I'm missing something, you don't need the CR either.

**i am by no means a control expert** lol


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## EB Electric (Feb 8, 2013)

Rochsolid said:


> I don't see a need for either of those contacts by your jog button, unless I'm missing something, you don't need the CR either.
> 
> **i am by no means a control expert** lol


You could not have a start-stop-jog station with that. You have eliminated the jog button. When you press the button which you have labelled 'jog' the coil will energize, seal in your M contact and it will stay running, the exact same as the start. You have drawn 2 starts. Whether the M contact is above or below has no effect, as long as the coil is energized and the stop button is not pressed you will have a path from line to neutral and it will seal in and run continuously. Just the way I see it.


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## Rochsolid (Aug 9, 2012)

EB Electric said:


> You could not have a start-stop-jog station with that. You have eliminated the jog button. When you press the button which you have labelled 'jog' the coil will energize, seal in your M contact and it will stay running, the exact same as the start. You have drawn 2 starts. Whether the M contact is above or below has no effect, as long as the coil is energized and the stop button is not pressed you will have a path from line to neutral and it will seal in and run continuously. Just the way I see it.


You're right, that was my bad on the drawing. Rushed it, this is what I was going for


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## EB Electric (Feb 8, 2013)

Rochsolid said:


> You're right, that was my bad on the drawing. Rushed it, this is what I was going for


Nice. That would work. The reason we used a control relay was for practice wiring up different devices and also with the control relay we could add in multiple jog buttons very quickly without splitting the circuit. Also we were using provided start-stop push button stations from allen bradley which were pre wired with the one side of stop already hooked to the start button. The jog button was created by just using the start from another start-stop push button station. If it was for a customer out in industry a start-stop-jog push button station all in one enclosure would be best, but hey we worked with what we had.


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## micromind (Aug 11, 2007)

Rochsolid said:


> You're right, that was my bad on the drawing. Rushed it, this is what I was going for


This will work, but only if the jog button is released slow enough that the starter drops out before the upper contact is closed. Most of the time, it's ok, but if someone releases the jog button really fast, the starter will stay latched in.


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## dronai (Apr 11, 2011)

What if you have a n/c contact that opens the seal in circuit when the jog button is pushed ?


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## xlink (Mar 12, 2012)

micromind said:


> This will work, but only if the jog button is released slow enough that the starter drops out before the upper contact is closed. Most of the time, it's ok, but if someone releases the jog button really fast, the starter will stay latched in.


It's the way I was taught to wire a jog button in school.


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## EB Electric (Feb 8, 2013)

dronai said:


> What if you have a n/c contact that opens the seal in circuit when the jog button is pushed ?


If you put a NC contact in series with the seal in NO contact the start button would become a jog. As soon as the coil energizes your hold in would close but then you NC would open, and you have another jog...


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## dronai (Apr 11, 2011)

EB Electric said:


> If you put a NC contact in series with the seal in NO contact the start button would become a jog. As soon as the coil energizes your hold in would close but then you NC would open, and you have another jog...


Not in series with seal in, in series with the jog. I'm thinking in logic form from my plc class we could add NC to open areas that we wanted to drop out.


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## dronai (Apr 11, 2011)

*Jog*

How is mine ?


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## Big John (May 23, 2010)

I was gonna say it was awesome and avoids all the potential problems caused by push-button timing, but then I saw the little off-center circle inside the "M" contactor and realized that coil must be defective and will never work. :whistling2:


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## dronai (Apr 11, 2011)

Big John said:


> I was gonna say it was awesome and avoids all the potential problems caused by push-button timing, but then I saw the little off-center circle inside the "M" contactor and realized that coil must be defective and will never work. :whistling2:


Had to notice :laughing: The software wont erase !!!


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## EB Electric (Feb 8, 2013)

dronai said:


> How is mine ?


That would work. It is the same as my initial drawing just re arranged a little bit . Can I ask what you are doing with those reference numbers :001_huh: ?? The reference numbers should identify the terminal on your start stop device, at least that's how I have been taught. Other then that good work :thumbsup:


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## dronai (Apr 11, 2011)

EB Electric said:


> That would work. It is the same as my initial drawing just re arranged a little bit . Can I ask what you are doing with those reference numbers :001_huh: ?? The reference numbers should identify the terminal on your start stop device, at least that's how I have been taught. Other then that good work :thumbsup:


I have to admit, I used Square D's wiring diagrams, and it was numbered similar in position to what I drew. But I see what your saying, every separate piece of wire would have to numbered to be able to locate it on the terminal screws.


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## JRaef (Mar 23, 2009)

dronai said:


> I have to admit, I used Square D's wiring diagrams, and it was numbered similar in position to what I drew. But I see what your saying, every separate piece of wire would have to numbered to be able to locate it on the terminal screws.


The "1/2/3" wire numbering system is likely an adaptation of the old JIC starter wiring standards. JIC was a precursor to NEMA, stood for Joint Industries Council (sounds like they should have been in Calif.). JIC was made up mostly of the big 3 automotive mfrs, who wanted all of their machine controls coming from OEMs to use common wiring methods so that the plant electricians could quickly troubleshoot. Wire number 1 was to always be the command circuit feed, 2 was always the seal-in circuit, 3 was always the coil circuit, regardless of if it was a two wire or three wire control circuit. If it was two wire control, then obviously wire number 2 was not used, but it was still labeled that way at the starter aux contact.

If you copied those numbers from Sq D, then obviously someone at Sq D has forgotten those standards. Probably the Frenchies made them change it because they didn't understand. JIC has been defunct for decades now, a lot of what used to be common knowledge has been lost.

So to that point, in the original diagram at the top, Ckt #1 is correct numbering per JIC, Ckt #2 is not, you would not put #3 on the circuit to the CR coil, only on the one to the M coil.


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## John Valdes (May 17, 2007)

EB Electric said:


> They are 95, 96 because these are the numbers on the NC O/L terminal that we were provided with. From what I was taught by the instructors 95, 96 is the industry standard for a NC thermal overload. It is an Allen Bradley if that makes any difference.





micromind said:


> Most IEC starters use 95/96 as the NC on the O/L relay.


They use these numbers on the terminals, but I would not use these numbers for the wiring. It would be to confusing.
If you had a panel full of starters and overloads, you would end up with many wires numbered 95 & 96. 

I would use number two (2) (or pick a number and stick with it) for all the return wires including all the OL relay wires. 
In fact it is not necessary to open the return wire through the Ol relay contact. You could break any circuit holding wire with the NC OL contact.
You could identify each set of OL contact wires with differing numbers if you like.

Now it is true IEC controls all have terminal markings. Like all the coils use A1 & A2. But it not important or required to use these terminal numbers for wire numbers.
In fact it would be wrong IMO. If you had all the coil wires marked A1 & A2, you would have no idea where to start looking for your particular issue or coil in question.




Rochsolid said:


> You're right, that was my bad on the drawing. Rushed it, this is what I was going for


You still need to extend the jog button switch with a dotted line down to the jog NO contact. Like this - - - - - - - - -
Show it so when you push the jog button, it opens the start circuit and momentarily closes the NO job contacts located directly below as shown.


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## bullmike (Jun 13, 2011)

practice , practice ,practice. I only started with the motor controls 4 years ago . It is something new & different everyday.


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## John Valdes (May 17, 2007)

dronai said:


> How is mine ?


You don't need a relay in a simple start/stop/jog circuit Dorian.

edit....Dorian it still works like you drew it. You just don't need the relay.


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## dronai (Apr 11, 2011)

John Valdes said:


> You don't need a relay in a simple start/stop/jog circuit Dorian.


I copied that from my Square D wiring diagram book  You know, looking at these, and working thru some of the drawings messes me up with the way you think with logic, and plc programming. It's almost one thing or the other.


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