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Old Jun 27, 2007, 05:53 AM
ChrisQuayle
ChrisQuayle
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Re: Single phase electric motor problem

jlh45 wrote:
> Austin Shackles Wrote:
>
>>On or around Fri, 22 Jun 2007 18:26:30 -0500, jlh45
>><jlh45.2sls4n@rcgroups.com> enlightened us thusly:
>>
>>
>>>For about 25 years I have had an Elektra Beckum table mounted 12 inch
>>>circular saw which for several years has been used rarely, maybe only
>>>one job in a year. The motor is a 2.2 kw, 2,800 rpm capacitor start
>>>single phase induction motor, which is rated at 11.5A.

>>
>>it sounds like the capacitor's had it. Chances are, for that
>>application,
>>it's a "constant capacitor" (i.e. low torque) motor, unless you know
>>otherwise. If so it hasn't got start windings nor an internal
>>starting
>>switch.
>>
>>--
>>Austin Shackles. www.ddol-las.net my opinions are just that
>>Travel The Galaxy! Meet Fascinating Life Forms...
>>------------------------------------------------\
>>
>>>> http://www.schlockmercenary.com/ << \ ...and Kill them.

>>
>>a webcartoon by Howard Tayler; I like it, maybe you will too!

>
>
>
>
> Thanks for the advice Austin.
>
> It is a 'constant capacitor' motor. I had a go at testing the capacitor
> and then had it checked when it appeared to be duff.
>
> Fitted a new capacitor and the motor now works perfectly.
>
> John
>
>


May be the cap, but it's also worth checking all wiring to the motor,
particularly the wiring to the start winding. If the motor has an
internal centrifical switch (motor clicks on startup and slowdown),
check the contacts and associated wiring for continuity. Use a battery
and lamp for continuity checking and wiggle all the wires while testing.

Wiring and switch contacts left unused for a time can corrode and
oxidise, especially in a damp environment...

Chris