Mis-Marked Motor leads

[sreid]

I spent an entire day last week trouble shooting a newly built machine that has a Sensorless Vector Drive, Three Phase Induction Motor variable speed axis. The motor is dual voltage, 9 wire. The problem turned out to be that leads T6 and T9 were reversed marked. In anyone's experience, how often does this occur?

 

[stardelta]

I havent seen it happen but I can imagine its an easy thing to confuse a 6 with a 9, particularly on a lead marking with no clear indication of what is up or down. It obviously wasnt tested when it left the factory or repair shop. Its food for thought though and if we ever come across a problem with a 9 LO motor it will be the first thing we check. Thanks for the tip!

 

[IRstuff]

Depends on the shop. We had a custom design with 3 prototypes. All 3 had miscoded phases. We had to phase each motor by hand.

TTFN

 

[itsmoked]

I've seen the smoke let out of 4 dry type buck/boost transformers because they were mislabeled.

 

[aolalde]

At least around 5% of motor terminals are missed for different reasons. Normally only a few are lost and a quick continuity test will be enough to re-identify those missing. A good practice should be not taking for granted that the terminals labeling is correct and tests for continuity and resistance before attempting to energize the motor.