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Electric Motors/delco model a5109 motor


QUESTION: It is a thermo type a motor model A5109 J-48  115 vac 2.9amp 1/6hp 1725rpm motor. Will only run after energizing if given a little spin by hand to get it going but the will run on its own. It is part of a whole house fan e would like to be able to just flip the switch and it runs any suggestions? Already tore apart and checked out looks fine not grounded to crime but does get a little ware after running a bit. Lubes where the oil ports are.

ANSWER: Does it have an internal stationary switch?
if so then the switch is not closed on stand still. Clean the contacts and adjust the switch arms so that the contacts are closed in stand still.
This is the start winding switch and it disengages the start winding after the motor starts up and and running.

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QUESTION: Not sure if it has this switch. There is a contact that is between the to and l terminals and it is always touching. Should this be not touching before the circuit is energized? I always get open and closed confused regarding electrical stuff.

The switch is screwed onto the inside of the bell housing. On the shaft will be a centrifugal switch, which flings away from the stationary switch as the motor speeds up.

Closed means the contacts touching.
Open means contacts not touching.

If the switch is Ok, then start winding ,maybe shorted or have an open circuit.
May have to get a motor shop to check it out. But then its cheaper to buy a new motor.

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Harcharan Singh Diocee


Electric motor winding redesign, AC and DC. Troubleshooting, motors controls generators. Vibration analysis, dynamic balancing, root cause analysis: electrical and mechanical.


thirty five years electro-mechanical and Senior Management


Journeyman Motor Rewinder, Millwright, Industrial Electrician, Vibration Analyst level II. Certified Electrical Technician ASTTBC, FSR Class B, in BC. Laser alignment specialist. Marine machinery repairs. Business Management Certificate. Last 19 yrs as Plant Manager

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