Optimizing Motor Start Frequency for 13000 Volt Switch Gear

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kraxup
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I am hoping that someone on here can give me some insight on what caused this. I have my idea; however, I would like someone to give their opinion also.

At work we have a 13000 volt motor that powers our compressor. How frequent can that size motor be started without causing the motor to overheat or the switch gear to catch fire?
We started this compressor 6 times in approx 5 hours and on the last start the switch gear buss caught fire.
I know a 4160 volt motor can only be tried 2 times within 30 minutes then it must rest for 4 hours before another attempt.
 
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kraxup said:
I am hoping that someone on here can give me some insight on what caused this. I have my idea; however, I would like someone to give their opinion also.

At work we have a 13000 volt motor that powers our compressor. How frequent can that size motor be started without causing the motor to overheat or the switch gear to catch fire?
We started this compressor 6 times in approx 5 hours and on the last start the switch gear buss caught fire.
I know a 4160 volt motor can only be tried 2 times within 30 minutes then it must rest for 4 hours before another attempt.

When you talked to the motor manufacturer, what did they say? Why are you asking us?
 
Your concern about the number of starts per hour for large motors is correct.
Overheating of the rotor windings & rotor structure is the primary concern in that case.
To say that starting the motor several times in a few hours caused the switchgear to catch fire is a
stretch however. A detailed investigation would be in order here to determine that exact cause of the fire.
Just a few of the things to be considered here are:
Is the switchgear bus rated adequately to serve the amount and type of all connected loads?
Is the breaker in the switchgear rated sufficiently to serve the motor?
When was the last time the breaker feeding the motor cleaned, and tested for proper timing and operation?
What type of protection is present in the switchgear, is it set properly and is it functioning ?
When was the last time the switchgear bus inspected/cleaned and tested?

There are many more things that should be investigated. I hope that nobody was injured or killed as a result of this incident.
 
Thank your for your reply. After fixing the switch gear and attempting to start the motor, on the 3rd attempt the motor burned up.