# Star/delta Motor Fault



## andyd1970 (Feb 22, 2009)

just connected a star/delta motor up ,checked all motor connections and starter box , the motor is running up on star then when changes over onto delta then the motor stops.Any ideas?Maybe delta windings faulty.


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## nick (Feb 14, 2008)

[quote=andyd1970 just connected a star/delta motor up ,checked all motor connections and starter box , the motor is running up on star then when changes over onto delta then the motor stops.Any ideas?Maybe delta windings faulty. Well tell me how many conductors are going to that motor 3 or 6 wires there is no star /delta seperate windings ,they are just changed star to a delta same windings by contactors in your starter if your wired correctly then its your motor or maybe your overloads the wrong size ? check your taps in the motor to the motors name plate it has a diagram 123 456 . start time to the run time should only be a one second click is it longer than that ? best to ya


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## brian john (Mar 11, 2007)

I use to service these units one of the most common issues is transition from start to run, if there is an overlap real issues happen fast.

Is this open or closed transition?

Check timing, check all aux contacts operate continuity check open closed, check mechanical interlocks.

Disconnect the line and load (once the unit is repaired) energize the secondary of the control transformer and then you can safely watch the operation safely.


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## John Valdes (May 17, 2007)

This one of the most common calls I get regarding wye/delta starting. If it runs in the wye configuration the motor is good. 

The problem lies in your connections, or contactors. Since it stops when it transfers to delta, I would make sure the two delta contactors are closing and making the circuit. Secondly, if the motor growls or tries to run in the opposite direction while going into delta, this is also a byproduct of mis-wiring and or contactor failure.

Do you have 6 or 12 leads? If you have 9, you have the wrong motor.

Assuming you have six leads try this out.
Swap leads 1&5 or 2&6 or 3&4. Do this swap one at a time. If the motor then tries to run in delta, but makes a racket or tries to reverse, swap 2 line leads. 

I am sorry this is a trial and error type troubleshooting process. But I know of no other way to be sure. You cannot trust connecting 1-1, 2-2, 3-3 ect...

Last resort is to call your local motor shop. However, they will perform similar steps that I have described in your facility. It must be done on site, not the motor shop.
Search this forum for member (micromind). He's real sharp on motors. Send him a PM.


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## nick (Feb 14, 2008)

Well biggest problem for me is when a post ask a question we only do new work i never think about if it ran before never doing service work we only think bad taps wrong wiring . So to the op did it run before ya did the work or is this a service call ? best to ya


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## rjnitesh (Jul 27, 2013)

*tripping issue*

one of the winding of motor may be open ...
so in star motor runs completely and during changeover in delta motor gets tripped...


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## eric7379 (Jan 5, 2010)

rjnitesh said:


> one of the winding of motor may be open ...
> so in star motor runs completely and during changeover in delta motor gets tripped...


This thread is over 4 years old. I hope that he found the answer/solution by now.


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