A colleague from the neighbouring department called to say he had a problem.A replacement three phase induction motor, drawn from the stores and wired, just refused to start.
Voltage okay?
Yes, all 3 phases terminal voltage 415V okay.
Maybe an overload or single-phasing. Does the overload relay trip?
No.
In that case it has no winding!
You crazy?!
No!
Okay, I'll check.
A little later the telephone rang again.
How did you guess?!
It turned out that someone in the motor rewinding department had sent an unwound motor back to the stores instead of a rewound one!
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