# Motor control class help😓



## Irwinote (Feb 28, 2015)

Very simple question to yall. Its new to me tho. Im having trouble understanding what wires go in 98 97 or 95 96 and what the ohm readings would be. Ive read my lessons and even glanced around future lessons on my student manual, and can't fingure it out.. I think the NC would mean the OLheaters or coils would be closed on normal operation. But where do the wires come from??? Are they coming from the auxiliary contacts on the side, and just hooked up in series?..and what would the ohm reading be? do the OL have a resistance in those terminals?


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## pjholguin (May 16, 2014)

I can't see your diagram.


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## dronai (Apr 11, 2011)

That is the other side of the coil going through the NC contact which will open when the OL's open. You can measure R through the coils of the starter
The other contact is the holding contact


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## Black Dog (Oct 16, 2011)




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## Black Dog (Oct 16, 2011)

pjholguin said:


> I can't see your diagram.



Look again...


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## don_resqcapt19 (Jul 18, 2010)

As you study motor controls, this Square D document is a good source.


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## Dock (Sep 24, 2014)

They are just NO and NC contacts. When the overload trips they reverse state.


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## pjholguin (May 16, 2014)

I can see clearly now the rain is gone! Lol I concur with Dock. Don has provided you a valuable document... Lots of good information!


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## Irwinote (Feb 28, 2015)

Yes in the morning im going to take a very good look at it..


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## Irwinote (Feb 28, 2015)

Thank you all


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## glen1971 (Oct 10, 2012)

dronai said:


> That is the other side of the coil going through the NC contact which will open when the OL's open. You can measure R through the coils of the starter
> The other contact is the holding contact


They are not holding contacts.. They are both overload contacts.. Usually the NC contacts (95/96) are in the control circuit to drop the controls out in case of an overload and the NO contacts (97/98) are used for overload annunciation, either a lamp on the cubicle door or PLC input...


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## RIVETER (Sep 26, 2009)

Irwinote said:


> Very simple question to yall. Its new to me tho. Im having trouble understanding what wires go in 98 97 or 95 96 and what the ohm readings would be. Ive read my lessons and even glanced around future lessons on my student manual, and can't fingure it out.. I think the NC would mean the OLheaters or coils would be closed on normal operation. But where do the wires come from??? Are they coming from the auxiliary contacts on the side, and just hooked up in series?..and what would the ohm reading be? do the OL have a resistance in those terminals?


If you are an apprentice you are not being instructed well. That is not your "bad".


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## Irwinote (Feb 28, 2015)

Well RIVETER ive notice all our homeworks have like 5 questions or so of lessons to come in the future. I guess to prepare us. get our heads thinking ahead idk.. Lol


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## Irwinote (Feb 28, 2015)

glen1971 said:


> They are not holding contacts.. They are both overload contacts.. Usually the NC contacts (95/96) are in the control circuit to drop the controls out in case of an overload and the NO contacts (97/98) are used for overload annunciation, either a lamp on the cubicle door or PLC input...


Thank you...i kinda see what your saying...and yes, they're. Actually overload contacts .but still need some clarification on how they wire up...i guess ill just get those few questions wrong this time and just wait for the instructer next week to help us on the board......


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## RIVETER (Sep 26, 2009)

Irwinote said:


> Well RIVETER ive notice all our homeworks have like 5 questions or so of lessons to come in the future. I guess to prepare us. get our heads thinking ahead idk.. Lol


Brand new...right...and already a smart ass. You may do okay.


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## Irwinote (Feb 28, 2015)

RIVETER said:


> Brand new...right...and already a smart ass. You may do okay.


Oh nononono i didnt mean to sound like that lol.. Its just ive finally realized they do that


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## RIVETER (Sep 26, 2009)

Irwinote said:


> Oh nononono i didnt mean to sound like that lol.. Its just ive finally realized they do that


Okay, I jumped the gun. Sorry.


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## pjholguin (May 16, 2014)

Irwinote said:


> Thank you...i kinda see what your saying...and yes, they're. Actually overload contacts .but still need some clarification on how they wire up...i guess ill just get those few questions wrong this time and just wait for the instructer next week to help us on the board......


NOT...put some more thought into this lessons. 1st. What is the purpose of the overload? How will using these contacts protect the motor? What is the first information about contacts that you are supposed to be taught?


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## Vintage Sounds (Oct 23, 2009)

Irwinote said:


> Thank you...i kinda see what your saying...and yes, they're. Actually overload contacts .but still need some clarification on how they wire up...i guess ill just get those few questions wrong this time and just wait for the instructer next week to help us on the board......


 how they wire up depends on what you're trying to accomplish. The holding contacts are on the left side of the contactor. 

In the case of the NC overload contacts(95/96) you would put them in series with the emergency stop button. If the overload trips there is no power to any of the rest of the control circuit. Think about why this is a good idea. The OLs are there to protect the motor. If they trip there should be no way to start the motor until they've been reset, either manually or after a pre-determined cooling off period.


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## Irwinote (Feb 28, 2015)

Vintage Sounds said:


> how they wire up depends on what you're trying to accomplish. The holding contacts are on the left side of the contactor.
> 
> In the case of the NC overload contacts(95/96) you would put them in series with the emergency stop button. If the overload trips there is no power to any of the rest of the control circuit. Think about why this is a good idea. The OLs are there to protect the motor. If they trip there should be no way to start the motor until they've been reset, either manually or after a pre-determined cooling off period.


WOW! THANK YOU SO VERY MUCH, and to everyone else!!!!...this really helped me understand... Last night i also found a very similar thread on here, that helped me understand the OL contacts are separate from the change of state by the contactor being energized!

http://www.electriciantalk.com/f2/n...re-start-stop-station-15172/#/forumsite/21022


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## Black Dog (Oct 16, 2011)

Irwinote said:


> WOW! THANK YOU SO VERY MUCH, and to everyone else!!!!...this really helped me understand... Last night i also found a very similar thread on here, that helped me understand the OL contacts are separate from the change of state by the contactor being energized!
> 
> http://www.electriciantalk.com/f2/n...re-start-stop-station-15172/#/forumsite/21022


Good for you-----keep working as hard as you can....:thumbsup:


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## Rollie73 (Sep 19, 2010)

Look at three contacts shown beside the coil marked as M1 and note that they are controlled by M1. M1(in this particular case) gets energized by an external 24 Vdc power supply......the negative of which is run to A2 and the positive is run through the start/stop station and through the O/L contacts (95/96) ad then on to A1.
Take a minute or two and trace how the power will through that circuit when the start button is pushed.

Now take note of how 95/96 are shown in this diagram as normally closed and are shown next to the O/L heaters. This indicates that they are operated by the O/L heaters and will be open by those in the event of an overload. 

You should then note that when 95/96 has been opened.....the circuit from 96 through 95 to A1 is nor longer complete. This means the power supply to A1 is gone and the coil is no longer energized so the contacts shown beside A1 will revert to their normally open state, and the motor will not run.

Ignore the 53/54 contacts for right now....they are the holding contacts controlled by M1 and will close when M1 gets briefly energized by the start button. They will hold closed until the stop button is pressed and keep M1 energized without needing to hold the start button in.


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## Irwinote (Feb 28, 2015)

glen1971 said:


> They are not holding contacts.. They are both overload contacts.. Usually the NC contacts (95/96) are in the control circuit to drop the controls out in case of an overload and the NO contacts (97/98) are used for overload annunciation, either a lamp on the cubicle door or PLC input...


AHA👍 now i see how a NO OL contacts would be used. knowing their correct opperation 


Makes it so much easier to understand...thnx again




pjholguin said:


> NOT...put some more thought into this lessons. 1st. What is the purpose of the overload? How will using these contacts protect the motor? What is the first information about contacts that you are supposed to be taught?


I put more thought into it! 🙉 thnx..i was able to figure out how both NO and NC would work on the OL. (thnx to all)....


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## Irwinote (Feb 28, 2015)

Uh nice diagram, helps to see it clearly!!!!..the overload contacts are completly seperate from the contactor (that was confusing at first 😣)...thank you


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## Rollie73 (Sep 19, 2010)

Irwinote said:


> Uh nice diagram, helps to see it clearly!!!!..the overload contacts are completly seperate from the contactor (that was confusing at first 😣)...thank you


 
No problem..........take some time to trace the way the power runs through that control circuit. It really helps if you understand how the power will flow through it on to the M1 coil.


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## dronai (Apr 11, 2011)

glen1971 said:


> They are not holding contacts.. They are both overload contacts.. Usually the NC contacts (95/96) are in the control circuit to drop the controls out in case of an overload and the NO contacts (97/98) are used for overload annunciation, either a lamp on the cubicle door or PLC input...


 
I know that  and you know I know that :thumbup: "Other "meaning the holding contact I thought he mentioned somewhere else.


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