# contactor issues



## micromind (Aug 11, 2007)

What sort of starter is it?


----------



## karl_r (Nov 5, 2012)

Siemens 3 phase magnetic starter 



Sent from my iPhone using electriciantalk.com


----------



## Safari (Jul 9, 2013)

Are you getting any humming sound after installing it?


----------



## Safari (Jul 9, 2013)

Try putting an MCCB or a fuse that should tell you where the problem is


----------



## ibew415 (Mar 23, 2014)

karl_r said:


> I just replaced a contactor and after only 3 hrs the coil smoked. I don't have a control transformer, I'm tapping onto one of the phases but it worked like that for years.
> Voltage seems to be good and OL is at 3A for a 3 phase 1hp motor.
> 
> Any idea what might be the cause? I've replaced the coil again and I'll test it tomorrow.


maybe a high leg system? Are you positive the coil voltage is correct?


----------



## JRaef (Mar 23, 2009)

ibew415 said:


> maybe a high leg system? Are you positive the coil voltage is correct?


First thing I thought of too.

karl_r,
You said you are using the line voltage, but what is the line voltage? Because you also said that you are tapping off of ONE of the phases, so assuming that the other side of the coil is going to a neutral, then that can be either a 120V coil that was tapped off of a 120/240V 3 phase 4 wire "high leg" system as ibew415 suggested, the coil voltage you get is only 120V from A or C phases to Neutral, but from B phase to Neutral will not b 120V, it will be 208V. The B phase being the "high leg" is typical by the way, but it depends on local utility conventions used.


----------



## Jlarson (Jun 28, 2009)

Sometimes we see somebody replace a starter on a high leg system without control xformers then they have to switch rotation and forget about the coil.


----------



## glen1971 (Oct 10, 2012)

Is the other side of the coil going to a neutral or is it going to the other line? Is the coil rated for the voltage you are trying to apply to it? If the OP didn't follow out the controls and is using a 120 volt coil on a 208 volt control system that would let some smoke out...


----------



## oliquir (Jan 13, 2011)

is it a 480v system?, do you have 277 volt on coil on a 240v coil?


----------



## Big John (May 23, 2010)

Read the nameplate, read your meter. You can't troubleshoot by guessing.


----------



## karl_r (Nov 5, 2012)

oliquir said:


> is it a 480v system?, do you have 277 volt on coil on a 240v coil?


it was the wrong coil all the time. Voltage was 208 and coil was rated for 120.

when supplier built the new contactor for me he probably installed the wrong coil.

thanks for your help guys, really appreciated:thumbup:


----------



## ibew415 (Mar 23, 2014)

karl_r said:


> it was the wrong coil all the time. Voltage was 208 and coil was rated for 120.
> 
> when supplier built the new contactor for me he probably installed the wrong coil.
> 
> thanks for your help guys, really appreciated:thumbup:



The supplier huh? Refer to flow chart!


----------



## dthurmond (Feb 7, 2011)

ibew415 said:


> The supplier huh? Refer to flow chart!


I am printing that out and posting it at work ! Lol


----------



## Big John (May 23, 2010)

I love that chart. Also a big fan of this one:


----------

