# square d nema size 3 magnetic motor starter ??



## miguel2213 (Jun 6, 2014)

well

troubleshooting this motor starter in the cabinet its 480 volt with a transformer in line to provide 120 for the coil I have power coming in I have power at the coil my start stop is wired properly according to the diagram provided by square d when I flip the main and activate the start I get nothing power at coil but will not engage any advice....


----------



## Black Dog (Oct 16, 2011)

miguel2213 said:


> well
> 
> troubleshooting this motor starter in the cabinet its 480 volt with a transformer in line to provide 120 for the coil I have power coming in I have power at the coil my start stop is wired properly according to the diagram provided by square d when I flip the main and activate the start I get nothing power at coil but will not engage any advice....


What happens when you cut power to the coil?


----------



## micromind (Aug 11, 2007)

The overload relay is factory wired in series with the neutral. If it is tripped, you'll have 120 to the coil but no return. A dead giveaway is 120 on both sides of the coil. 

Another possibility is that the coil is burned up.


----------



## denny3992 (Jul 12, 2010)

micromind said:


> The overload relay is factory wired in series with the neutral. If it is tripped, you'll have 120 to the coil but no return. A dead giveaway is 120 on both sides of the coil.
> 
> Another possibility is that the coil is burned up.


What he said


----------



## miguel2213 (Jun 6, 2014)

I have ohmed the coil and get 9 ohms how could I reset the relay or no possibility of doing that and it's fine when removing 120 from coil I still get nothing I don't understand it we have a spare can with a similar motor starter that was existing I'll try to use it see what I get back


----------



## miguel2213 (Jun 6, 2014)

on a existing motor started for a 10HP motor im reading 31 ohms 
on the one trouble shooting fro 35HP motor im reading 8 ohms ????????


----------



## Chris Kennedy (Nov 19, 2007)

micromind said:


> The overload relay is factory wired in series with the neutral. If it is tripped, you'll have 120 to the coil but no return. A dead giveaway is 120 on both sides of the coil.


Also agree first place to start.


----------



## micromind (Aug 11, 2007)

miguel2213 said:


> on a existing motor started for a 10HP motor im reading 31 ohms
> on the one trouble shooting fro 35HP motor im reading 8 ohms ????????


The coil for the 10HP motor is likely a size 1 or 2. It is smaller than a size 3, therefore the larger coil would be expected to have lower resistance.


----------



## micromind (Aug 11, 2007)

miguel2213 said:


> I have ohmed the coil and get 9 ohms how could I reset the relay or no possibility of doing that and it's fine when removing 120 from coil I still get nothing I don't understand it we have a spare can with a similar motor starter that was existing I'll try to use it see what I get back


The coil is very likely ok. 

Measure resistance from the neutral side of the transformer to one side of the coil. The reading should be close to 0 or the resistance of the coil. If it's open, look at the overload relay. It might need to be reset, or it could be bad.


----------



## miguel2213 (Jun 6, 2014)

thanks for the input replaced the existing motor starter with one in another can same starter and still didn't get anything took the front plate off and decided to engage the coil manually to see if the motor would come on and nothing got a spark and some smoke SOB


----------



## Chrisibew440 (Sep 13, 2013)

miguel2213 said:


> thanks for the input replaced the existing motor starter with one in another can same starter and still didn't get anything took the front plate off and decided to engage the coil manually to see if the motor would come on and nothing got a spark and some smoke SOB


thats a big motor to be energizing manually. smoke and fire is what will happen, whoops. youve got a lot of in rush current when you do that manually and your not fast enough to make all contacts at the same time.


----------



## miguel2213 (Jun 6, 2014)

Figured that out pretty quick lol could it be that both relays are bad in these starters other than that it's a dead ball for me good thing we have our main pipeline pump it's running fine on a soft start system but would still like to get #2 running


----------



## varmit (Apr 19, 2009)

If you have 120 volts between both coil terminals and the starter does not engage, the coil has probably failed. If have 120 volts to the coil and no "neutral" the overload relay is probably either tripped or faulty. There could also be a neutral wire loose, broken or missing somewhere.

I have also seen equipment where the "neutral" was ran through some or all of the control devices and the "hot" went strait to the coil. I see this on OEM equipment sometimes. This method is wrong.


----------



## micromind (Aug 11, 2007)

When the starters were installed, were the heaters installed new or changed? If so, Square D starters need to have the O/L reset or the coil will not be energized.


----------



## sparkywannabee (Jan 29, 2013)

Chrisibew440 said:


> thats a big motor to be energizing manually. smoke and fire is what will happen, whoops. youve got a lot of in rush current when you do that manually and your not fast enough to make all contacts at the same time.


I have manually pushed in the coil on 50 HP motors, hundreds of times, never seen sparks and especially smoke, maybe a little momentary arcing in the beginning. If i suspect it might a bad motor, I usually stand to the side of the panel and don't use the hand i jerk off with.


----------



## sparkywannabee (Jan 29, 2013)

varmit said:


> If you have 120 volts between both coil terminals and the starter does not engage, the coil has probably failed. If have 120 volts to the coil and no "neutral" the overload relay is probably either tripped or faulty. There could also be a neutral wire loose, broken or missing somewhere.
> 
> I have also seen equipment where the "neutral" was ran through some or all of the control devices and the "hot" went strait to the coil. I see this on OEM equipment sometimes. This method is wrong.


Varmit, we have trusty old baling machine and the neutral for the coil off the motor starter is wired up through limit switches and such, as you mentioned. I am just curious, why do you think this is wrong.


----------



## Jlarson (Jun 28, 2009)

sparkywannabee said:


> I have manually pushed in the coil on 50 HP motors, hundreds of times, never seen sparks and especially smoke, maybe a little momentary arcing in the beginning. If i suspect it might a bad motor, I usually stand to the side of the panel and don't use the hand i jerk off with.


That's a great way to destroy contacts, your hand does not have enough force to hold in larger starters. 



sparkywannabee said:


> Varmit, we have trusty old baling machine and the neutral for the coil off the motor starter is wired up through limit switches and such, as you mentioned. I am just curious, why do you think this is wrong.



It can be a saftey hazard, ie a ground fault could defeat a limit or interlock and it is also a code violation.


----------



## sparkywannabee (Jan 29, 2013)

Not sure about that, i use my large flathead and it goes in pretty easy, as far as the coil can pull it anyway, I don't usually hold it in for longer than a few seconds.


----------



## Jlarson (Jun 28, 2009)

You still aren't strong enough to overcome the magnetic forces involved caused by the current flow. Doing that does cause chattering of the contacts.


----------



## sparkywannabee (Jan 29, 2013)

maybe so, but you know what, the 50HP starters are over 25 yrs old, been energized manually by several electricians over the years, run 24/7, and never been replaced. We've changed some of the smaller ones but never any of the supply fan motors.


----------



## varmit (Apr 19, 2009)

The famous "We have always done it this way." Luck does run out someday. Much better to use a jumper to the coil for testing. You can even put a momentary push button on a piece of wire/cable to give you a little distance from the starter in case it goes boom.

Neutral through control devices: Problems as jlarson noted.

Sometimes, on older starters, the coil will mechanically wear so much that it will bind and not close the power contacts. If so, the coil can quickly overheat and let the smoke out.


----------



## varmit (Apr 19, 2009)

sparkywannabee said:


> maybe so, but you know what, the 50HP starters are over 25 yrs old, been energized manually by several electricians over the years, run 24/7, and never been replaced. We've changed some of the smaller ones but never any of the supply fan motors.


This could be an origin to the problem. Each time the coil is manually pushed in by hand the contacts are damaged by contact bounce that is not detectable from outside. 

If you are getting "sparks and smoke" when forcing the coil you may have:
(A) A ground fault in the motor or motor wiring.
(B) One or more power contacts are worn out in the starter.
(C) As stated previously, YOU CAN NOT MANUALLY PUSH THE CONTACTOR CLOSED.


----------



## JRaef (Mar 23, 2009)

miguel2213 said:


> Figured that out pretty quick lol could it be that both relays are bad in these starters other than that it's a dead ball for me good thing we have our main pipeline pump it's running fine on a soft start system but would still like to get #2 running


You have never answered the basic questions.

Do you have the heater elements installed?

If so, or if it is an electronic overload relay, did you push the overload reset button?

And PLEASE use punctuation, it is very difficult to follow your run-on sentences.


----------



## JRaef (Mar 23, 2009)

sparkywannabee said:


> maybe so, but you know what, the 50HP starters are over 25 yrs old, been energized manually by several electricians over the years, run 24/7, and never been replaced. We've changed some of the smaller ones but never any of the supply fan motors.


Just because you have been doing something inappropriate for 25 years does not meant it must thereby not be inappropriate and that NEVER makes it OK to tell others to do it.

1) as the others have said, the contacts are designed to force themselves apart via magnetic repulsion as soon as the coil is released. The mechanical force of the coil is carefully engineered to be strong enough to overcome those repulsion forces. You MIGHT be able to exert enough force, or you might not. You have no way of knowing and if you do not, the contacts vibrate open and closed at 120 cycles, which melts the contact material. This at the very least shortens the life, but at worst you can cause them to weld, then have no means to shut off the motor other than the disconnect, and since you obviously have the door open to do this inappropriate task, you might get a serious arc flash when you do. But of course, you will have your full PPE 4 gear on, right?

2) after doing this numerous times and vaporizing the contact material, you are SERIOUSLY increasing the risk of a flashover from creapage across the insulating material surfaces that are now getting coated with vaporized contact material.

I have seen the flash-bang from the "screwdriver control method" first hand, and for the guy that did it, it was the first time he had ever tried it. While I believe you that you have not had an incedent in 25 years of doing this, that can only be attributed to luck, and luck is not a valid safety strategy.


----------



## John Valdes (May 17, 2007)

miguel2213 said:


> thanks for the input replaced the existing motor starter with one in another can same starter and still didn't get anything took the front plate off and decided to engage the coil manually to see if the motor would come on and nothing got a spark and some smoke SOB


Stupid move. Manually pushing the starter in is very dangerous.
What if the motor or motor conductors are shorted?
If you have any respect for yourself and this trade, find a safer way to test a starter.



sparkywannabee said:


> I have manually pushed in the coil on 50 HP motors, hundreds of times, never seen sparks and especially smoke, maybe a little momentary arcing in the beginning. If i suspect it might a bad motor, I usually stand to the side of the panel and don't use the hand i jerk off with.


One day, you will push the starter in, and you will be in for a very big surprise. I cannot believe you guys are doing these things.
I cannot say I have never done this before. But it was a long time ago when I had no idea as to what I was doing.



varmit said:


> The famous "We have always done it this way." Luck does run out someday. Much better to use a jumper to the coil for testing. You can even put a momentary push button on a piece of wire/cable to give you a little distance from the starter in case it goes boom.


Fully agree. I would give one warning and if I saw the same guy do it again, he would be gone.

OP. You pulled a starter because you did not know why it would not energize. Why didn't you troubleshoot the starter then? On the bench?
This way you could have found your problem along with getting some basic control experience.

You can also turn off the motor breaker for troubleshooting. Remove the 480 volts. The controls will still work if the control transformer is isolated from the load side of the motor circuit breaker.. This way at least you will not be dealing with a 480 volt arc flash.


----------



## sparkywannabee (Jan 29, 2013)

I never said "That's the way we've always done it", and how come, in 20 years of doing this electricity stuff, if this is as big a deal as you all say it is, seems like the contacters that I always change are the ones that never get their coils pushed in, not the ones that do.


----------



## John Valdes (May 17, 2007)

sparkywannabee said:


> I never said "That's the way we've always done it", and how come, in 20 years of doing this electricity stuff, if this is as big a deal as you all say it is, seems like the contacters that I always change are the ones that never get their coils pushed in, not the ones that do.


I tried to warn you about an unsafe practice. This is all I wanted to do.
Can you not wrap your mind around the possibility the motor or conductors are shorted. Have you ever seen an arc flash? And if you have, why would you put yourself into a position to have that arc flash happen right in front of you, or even to the side? 
Don't you get the idea that when you push in a starter, you are taking a huge gamble?
Its not a gamble anyone should take. Especially when you are the one that should know how dangerous it is.


----------



## Safari (Jul 9, 2013)

miguel2213 said:


> well
> 
> troubleshooting this motor starter in the cabinet its 480 volt with a transformer in line to provide 120 for the coil I have power coming in I have power at the coil my start stop is wired properly according to the diagram provided by square d when I flip the main and activate the start I get nothing power at coil but will not engage any advice....


I will start by disconnecting the load and working with the controls.

Sent from my HUAWEI Y210-0100 using Tapatalk 2


----------



## just the cowboy (Sep 4, 2013)

The only time I got hit with 480v was pushing in an old starter and watching for rotation. It went in one finger and blew a small hole in the other, so it is not only a fault. And if you are pushing with a screwdriver and it slips, BOOM


----------

