Originally Posted by
Malcolm McLeod
^+1
Randy, this is a great place to apply 'law of halves' to trouble-shoot electrical problems. Test in the middle of a given system and determine which 'side' is bad. Test again in the ~ middle of that bad half and isolate the bad half of that half ...... repeat as necessary. The problem's possible location gets narrowed down quickly.
Test when the motor won't start*:
- If you have power at the output side of the controls (= approx middle?) , then the problem is in the last half of the system (wiring to the motor, or in the motor). First half is fine.
- - If you measure the voltage at the motor and there is rated voltage, then the problem is in the motor. (All else is fine.)
- - If you measure the voltage at the motor and there is no voltage, then the problem is in the wire between the starter & motor.
- If you have no power at the output side of the controls, then the problem is in the first half of the system (power supply or starter). Second half may be fine, but is yet to be determined.
....repeat until you find the 'break' in the system.
(I use 'half' loosely, pick convenient spots to test voltage that have accessible points (terminals, wire nuts, etc).
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* Please remove the belt and use good judgement when the controls/JBs/peckerhead are open!
Problem is intermittent and he can not gain access to the motor connections when its installed.
Retired Guy- Central Iowa.HVAC/R , Cloudray Galvo Fiber , -Windows 10