Motor/Starter Incompatibilities, growing problem

[DennisHarding]

In the past 26 years I have come accross Motor/Starter incompatibilities several times. This problem seems to be growing. The most common is with 2 speed motor setups, dual winding starters and single winding motors. I have come across the part winding start motor and a "Full voltage" starter on my present job. Does anyone know of workarounds for these problems? I also feel that our Engineer schools should address this in the classroom. Any comments would be appreciated.

 

[Marke]

Not only are there incompatibilities between motors and starters, there are also many installations where the motor / starter combination are not appropriate for the driven load. When you look at the results achieved, they often as bad or worse than full voltage starting. Either engineer the whole starting process or use full voltage starting. This is made worse by "high efficiency" motors that have poor starting characteristics.
I agree, better education is required!! Mark Empson

http://www.lmphotonics.com

 

[busbar]

This often stems from increasingly “fast-track” project management and miscommunication or no communication between vendors, with the growing and continued hope that contractor or facility owner won’t notice prior to project wrap up, paid accounts receivable and warrantee expiration. There are cases where the prime method of customer service is to “wear down” installing and end-user firms with repeated, vehemently non-responsive attitudes.

Online tutorial literature on motor control may be found at sites like ab.com, squared.com or cutler-hammer.com.

 

[acmotorengineer]

Dennis:

Not all two speed motors use the same starting connection.
Not all part winding motors use the same connection.
Not all dual voltage motors use the same connection.
.... etc .... etc ..... etc .....

Even with my experience, I have no idea what motor connection would be used, without asking.

Re: Marke,

what "poor" starting characteristic were you referring to?

I agree with your statement about "right" motor, "right" starter - - "wrong" combination.

This happens frequently with inverters. The guy that bought a 100HP Inverter for a 100HP Motor. The motor happened to be a 14 Pole which has 125% increase in full load current over NEC Full Load Amps. Consequently the inverter was too small. He blamed the motor manufacturer and wanted them to "correct" the motor.

Or the guy that bought a two speed, two winding starter and ordered a two speed, one winding motor - because the motor was less expensive.

Or the guy that bought a 4 pole - 2 pole, part winding starter, because it was also cheaper and got a 3 pole - 3 pole part winding motor.