Electric dryer - thermal fuse question

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:Hi : :Our Sears electric dryer went completely dead about 2 seconds after :pressing the "push to start" button. Completely dead - as in no power :even to the 10 watt light inside the drum. : :I've located a 196 degree thermal fuse in-line to the motor that could :be responsible for complete power loss to everything 120v if it's gone :bad. With both leads disconnected I'm getting a reading on that thermal :fuse that flips between .5 and .6 ohms. (Lowest scale on the meter I :have on hand is 200 ohms.) : :To my knowledge I should be reading zero ohms if the fuse is good. Is a :paltry .5 ohm reading enough to indicate that a thermal fuse is bad? : :Thanks : :Rick

There is nothing wrong with the fuse then.

Just try shorting the test leads on your meter and you will probably read something like 0.2 Ohms resistance anyway. Unless your meter has a "ZERO Ohms" function you can't compensate for the lead resistance.

The 0.5 or 0.6 ohms is probably the same reading you get with the probes shorted. The fuse should read so close to 0 ohms that your meter won't see the difference.

If the resistance of the fuse really is 0.5 or 0.6 ohms, then there is a problem with it. But fuses almost always fail open.

Or, measure the AC voltage across it when the dryer is supposed to be on.

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Have you tried turning on the dryer again? The fuse might very well read close to zero simply because it's reset. If that's the case, then the problem is a short further down the line.

--- the Lady from Philadelphia

The protection in your motor is fine, look else where. Your meter will not read 0 even if you cross the leads unless you have an analog with cal on it.

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Many digital meters have a "zero-cal" pushbutton.

REL mode is not accurate. As it saids. It's relative and so is the same with analog meters.

for a true accurate reading at low ohms, you need a Kevin leaded meter.

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Thank you to everyone who replied.

Regarding the meter situation: If it matters it *does* read zero ohms with the leads crossed. It's an inexpensive, $20.00 LCD display type meter. I had checked the thermal fuse a few times and it consistently gives a reading that hovers back and forth from .5 ohms to .6 ohms each time it's tested. (Yes - both leads to the fuse have been removed for testing.)

I think I'm going to bypass it and reapply power to see what happens. I'm not looking to start or run the dryer with the thermal fuse bypassed. I just want to either rule it in or out - see if the 10 watt light inside the drum will come back on (or not.)

The way I'm reading the wiring diagram for this model - a Sears Ken"less these days" - it does not use a drop resistor to supply 120v to the timer & motor etc. It uses 1/2 the 240v feed to supply 120v to the motor and electronics. And it's also the first time I've seen a dryer put a thermal fuse in-line with the motor. (Of course, there is a second thermal fuse in the 240v supplied to the heater.)

The only other thing I can see in the wiring diagram that would kill all power to the 120 volt stuff - and make the drum light inoperable as well

- would be a defective dryer door switch. More disassembly... I'm not as inclined to suspect the door switch because, hell, this dryer is barely two years old! But with the "quality" of Kenmore appliances these days... Exasperating. First the dehumidifier that crapped twice in 15 months. Now a dryer that went bust in two years. Kenmore? I don't know what the hell is going on with Sears, and I thought I'd never say this, but Never Again.

Rick

DO NOT DO THIS. You don't know what's wrong with the dryer. The fuse is there to protect you and the equipment.

Start by turning it on and see if it runs briefly as it did before. If it shuts off (as I think it will), you can check the fuse quickly to see if it's opened. If it has, you know there is some other problem, and you can use the schematic to start tracking it down.

A corollary to Murphy's Law is that the component that's hardest to get at (in this case the door switch) is the most likely to be defective.

Find where the wires from the switch go, and check _its_ continuity.

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RE: The "Door Switch" - while you might be correct - do NOT overlook the obvious. Sometimes it is the simplest of things that goes bad. AND not always in the easiest of places to get to!

RE: Sears - A neighbor of mine - asked me to take him to the store to buy a "rototiller" to till some ground for planting. He got the Tiller - brought it home - it worked for an hour - then quit. He called them - told them what was going on. They told him bring it back. They tried to tell him - he was not supposed to use it for the purpose he was - "Tilling". I'm like - what the hell do you do with it then, stand it in a corner and stare at it? Any "Farmer" would laugh you people out of town - to hear you say that. They offered him a cheaper model for the same price - a joke! He told them absolutely not. He got his money back - we went a mile out the road to a Lowes - where he bought one - and no trouble with it at all. That store - is out of business - having gone out about November of 07.

I have an older dryer my parents bought ($80) in the mid to late 60s. Since that time - the pulley had to be replaced twice - the belt 4 times - once because the cross arm sort of shifted in time and cut it - prematurely. The Pig Tail - once. It still works like a charm! "I" have repaired it all but once - my brother in law repaired the first broken belt. That dryer has definately paid for itself many times. It was made by G.E. That dryer is a

120 Volt - 15 Amp Dryer. It has like a 3 hour timer on it. It "does" get hot - believe it or not. Unless you overload it severly, the clothes get dry in one cycle. My electric bill is only about $40 tops per month - all other uses included.

One of the most common faults on tumble dryers over here in the UK is the door switch or the method of operating same, sometimes a plastic peg on the door which can get broken off, or a fitting on one of the hinges.

That`s where I would start looking

Ron(UK)

I assume you did check the AC outlet or power wiring!

Also, older installations may have a pair of fuses, on one each leg of the 115-0-115 V service. Sometimes, only one of these fuses blows (possibly for no good reason) killing power to the 120 V stuff.

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We have a Sear Kenmore from at least 1970, possibly much earlier. (It was in the house when we moved in in 1980). It (crossed fingers) has never needed service.

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They had "quality" back then! Better quality, less stringent laws, rules, etc... to oversee. I'll attempt a repair at an older item any time. So long as the timer keeps working - the rest should be an easy fix for you if it goes whacko. My mother had a wringer washer - which I used up til about 1999. It finally died. Parts were still available - but more than a new washer would cost. So, I bought a new "modern" washer. It only lasted 6 years or so. The damned transmission went bad in it - cost to replace - $300. Out the door it went.

TVs used to be good for at least 10-15 years - give or take some maintenance. Today - if you get a year out of them, you're damned lucky.

We have a Big Screen tv at our Fire Department in the Lounge. It is only about 3 years old and has been repaired at least that many times - already. Not only that - but the damned thing - for being solid state - takes as long as a "tube" type TV takes - to come on. That is ridiculous.

I'll venture that what you are looking at is not a real thermal fuse, a device with a metal link that melts (fuses) when it fails. Those will not recover at all after failure.

More likely what you have is a thermostatic switch that opens a circuit by the motion of a bimetal strip. These will recover when cool. Replace it and you should be done.

That would be consistent with the symptoms you have.

Charlie

We had a Sears electric dryer, circa early 1980's. I replaced the heater coil in it once. It then became unrepairable when the motor start/run switch cracked in three pieces and Sears no longer stocked the part. The only way we could get the switch replaced was to buy a new motor with a start/run switch mounted on it. The cost for the motor was $130.00. Hindsight being what it is, it would have been a better idea to buy the motor than a new Sears appliance.

Caveat emptor...

Rick

Thanks Sam

The AC cord (3 wire setup) and wiring block for continuity? Yes.

The 240v socket? No. How do you check it properly? 0-115 on both sides? Or 115 to 115 for 240 volts? All of the "how to" books avoid the testing procedure for 240v outlets and I don't want to do it until I know how to do it.

FWIW it's a dual circuit breaker on the panel. It didn't trip when the dryer went dead.

Rick

Either way. The latter is probably more reliable. Of course, two 115's only make 230, but you might have two 120's. :-)

All of the "how to" books avoid the testing

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