|
Posted by Jeff Wisnia on May 11, 2007, 2:37 pm
doordoc@prodigy.net wrote:
> Maybe I didn't word that quite properly & should of said inside of the
> cover. Personally i was never able to find the actual short &
> inspecting the motor winding wouldn't help at all, but I have seen
> that exact problem in Genie openers numerous times and it would never
> trip a breaker (they don't have any internal fuses). Since I couldn't
> find the short, I can't tell you why the breaker doesn't trip.
>
> The clue is when he spins the screw (thus the motor winding turns) the
> opener will start working again for a while until the motor winding
> stops again in that one spot.
>
> The motor has a built in thermal overload that the incoming power goes
> thru to the rest of the unit, so if the power isn't going thru the
> overload it kills power to the entire unit & thus no lights will come
> on & the opener does not make a sound.
>
> I can tell you from experience that you can change any other part in
> the opener as many times as you want but the problem will never go
> away completely until you change the motor winding & once the winding
> is changed the problem does not re-occur. The difficult part in
> troubleshooting it is that the problem is intermittent (any minor
> movement of the winding & the problem will disappear & may not come
> back for days) & that you can't see the winding while the opener is
> operational.
>
> He asked for advice and I gave him mine from experience of working on
> hundreds of these openers since 1978 (did full time service from then
> until the late 90's) & others are certainly free to offer any
> suggestions or ideas that come to their mind.
>
> DoorDoc
> www.ActionDoor.com
>
>
>
I defer to your significant experience, after your rephrasing.
But, just so I might better understand things, do those particular
openers use "universal" motors with brushes, or induction motors?
If they have brushes, I can well believe that when the brushes wear down
or get sticky in their holders the motor could stop with a brush not
quite touching a low spot on the commutator, and a little fiddling with
the motor shaft could let it start the next time. (Just like whacking a
"dead" starter motor on a car with a BFH to get one more start out of it.)
But if they are induction motors, I don't quite get what you mean by
"(thus the motor winding turns)" unless by "winding" you are referring
to the bars on a squirrel cage rotor. One of those might get
disconnected from the rings on the ends of the rotor and fail to produce
enough starting torque after stopping in just the wrong place.
If that happened I can surely believe that the motor would draw enough
current to heat to the point where a thermal overload could kick open,
and while it was open, the pilot light could go out, as you explained.
But, I'd call the actual fault an "open" and not a "short". <G>
So, in summary, I now concur with your condemnation of the motor in his
unit.
Peace,
Jeff
--
Jeffry Wisnia
(W1BSV + Brass Rat '57 EE)
The speed of light is 1.8*10^12 furlongs per fortnight.
>
>
>>door...@prodigy.net wrote:
>>
>>>The motor winding is shorting out on the inside of the motor case when
>>>it stops in a certain spot. You can replace the motor winding, but for
>>>what you will spend & the time involved I would suggest you buy a new
>>>one.
>>
>>Uh, ..... unless he's got the unit plugged into an ungrounded circuit,
>>just why isn't it blowing a breaker or fuse upstream.
>>
>>And if it ISN'T grounded, why should that short remove power from the
>>wall pushbutton light?
>>
>>Much more likely there's a "loose disconnection" disconnecting power
>>from the transformer. I had that happen to one of my Craftsman openers
>>many years ago, the weight of the power transformer hanging off a
>>vertical circuit board, combined with the vibration every time the unit
>>operated caused one of the transformer's soldered joints to crack.
>>
>>I resoldered it and beefed up the transformer support with a small block
>>of wood epoxied in place. I'd swear that was over ten years ago and it's
>>still goung strong.
>>
>>So, to the OP, remove the unit's cover, and with the power on CAREFULLY
>>use a small piece of dowel to push and wiggle things inside while
>>someone watches the pushbutton light. You may find a repairable loose
>>electrical connection.
>>
>>HTH,
>>
>>Jeff
>>
>>
>>
>>
>>
>>
>>>DoorDoc
>>>www.ActionDoor.com
>>
>>>On May 11, 6:10 am, prfes...@hotmail.com wrote:
>>
>>>>My Genieopenerappears to have quit. No light at the wall
>>>>pushbutton, no lights on the sensors at thedoor, won't open or close,
>>>>of course. Power at the outlet---I checked. Similar action about a
>>>>week ago; I opened up the case and turned the shaft of the motor by
>>>>hand (figuring something was stuck), and that brought it back to
>>>>life. The nearest repair place is two hours and thirty bucks' worth
>>>>of gas away. Any ideas before I go out and buy a new one?
>>
>>>>Thanks -- Terry
>>
>>--
>>Jeffry Wisnia
>>(W1BSV + Brass Rat '57 EE)
>>The speed of light is 1.8*10^12 furlongs per fortnight.- Hide quoted text -
>>
>>- Show quoted text -
>
>
>
| 
Yahoo! 
Google 
Windows Live 
del.icio.us 
digg 
Netscape 
XML Sitemap