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Non-Aviation Question - Electric Stove Switch

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mapratherid(at)GMAIL.COM
Guest

Posted: Fri Apr 20, 2012 11:52 am Post subject: Non-Aviation Question - Electric Stove Switch

Listers,



I acquired a fairly late model Kenmore electric range from craigslist

a few days ago.  My first pass inspection verified that the oven,

clock, and all of the burners worked.. So far, so good.  However, the

first time I attempted to cook on one of the large burners I learned

that it had only one setting - 100% on.  Grrr.



I did a little blind checking and found that a replacement control

switch was $91 from Sears - my good deal on the range was/is in

jeopardy.. So, I started debugging - swapping the switch into the

location for the other large burner.  The bad behavior tracked with

the switch - good!



Feeling nothing to lose, I disassembled the switch and found that a

set of contacts within the switch was stuck (welded?) closed - that

explained the behavior.  I managed to pry the contacts open and spent

a bit of time filing on them - not sure that does any good..  I

reassembled everything and it all seems to be working properly now.

If I hold my head close to the panel, I can hear the bimetallic switch

cycling the power to the burner on and off.



Now for my questions:



 - What caused the contacts to weld closed?  It's a fairly new range,

so it doesn't seem like it was just a large number of cycles.  I'm in

New Mexico, which has frequent lightning storms.  Could the errant

charge from a lightning strike cause the contacts to get welded

closed?  Maybe the previous owners of the stove used it for cooking

meth - so it has an abnormal number of cycles on it?



 - Will my efforts at splitting the contacts and cleaning them up

yield a switch that's reasonably long-lived and reliable?  Or should I

just order a replacement switch now..  I found an alternate source of

the switch - for $30.  Is there something else I can do to the switch

contacts to help them out?



I read an article that suggests that contacts get hottest during the

arc associated with the switch opening.  And that immediately

re-closing the switch offers the largest risk for welding the

contacts.  I could imagine an unattended little kid playing with the

dial until it failed closed - it makes a very subtle, but kind of cool

buzz-click every time the contacts close or open...

Regards,



Matt-

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raymondj(at)frontiernet.n
Guest

Posted: Fri Apr 20, 2012 12:45 pm Post subject: Non-Aviation Question - Electric Stove Switch

FWIW



If the burner is thermostatically controlled, it's  possible the temp 

control system might have caused rapid switching leading to the welding.



do not archive



Raymond Julian

Kettle River, MN



"And you know that I could have me a million more friends,

and all I'd have to lose is my point of view." - John Prine



On 04/20/2012 02:49 PM, Matt Prather wrote:

 	  Quote: 	
		   



 Listers,



 I acquired a fairly late model Kenmore electric range from craigslist

 a few days ago.  My first pass inspection verified that the oven,

 clock, and all of the burners worked.. So far, so good.  However, the

 first time I attempted to cook on one of the large burners I learned

 that it had only one setting - 100% on.  Grrr.



 I did a little blind checking and found that a replacement control

 switch was $91 from Sears - my good deal on the range was/is in

 jeopardy.. So, I started debugging - swapping the switch into the

 location for the other large burner.  The bad behavior tracked with

 the switch - good!



 Feeling nothing to lose, I disassembled the switch and found that a

 set of contacts within the switch was stuck (welded?) closed - that

 explained the behavior.  I managed to pry the contacts open and spent

 a bit of time filing on them - not sure that does any good..  I

 reassembled everything and it all seems to be working properly now.

 If I hold my head close to the panel, I can hear the bimetallic switch

 cycling the power to the burner on and off.



 Now for my questions:



   - What caused the contacts to weld closed?  It's a fairly new range,

 so it doesn't seem like it was just a large number of cycles.  I'm in

 New Mexico, which has frequent lightning storms.  Could the errant

 charge from a lightning strike cause the contacts to get welded

 closed?  Maybe the previous owners of the stove used it for cooking

 meth - so it has an abnormal number of cycles on it?



   - Will my efforts at splitting the contacts and cleaning them up

 yield a switch that's reasonably long-lived and reliable?  Or should I

 just order a replacement switch now..  I found an alternate source of

 the switch - for $30.  Is there something else I can do to the switch

 contacts to help them out?



 I read an article that suggests that contacts get hottest during the

 arc associated with the switch opening.  And that immediately

 re-closing the switch offers the largest risk for welding the

 contacts.  I could imagine an unattended little kid playing with the

 dial until it failed closed - it makes a very subtle, but kind of cool

 buzz-click every time the contacts close or open...

 Regards,



 Matt-

- The Matronics AeroElectric-List Email Forum -

Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:

http://www.matronics.com/Navigator?AeroElectric-List

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