Glow bar igniter

[Stumpy]

Having trouble with my Fridgidaire oven. Sometimes is just doesn't heat up.
Looked up the igniter function referenced in link below.

Don't most resistance heaters increase in resistance as they heat up? Maybe
the igniter is not NiChrome.


6-4 "The same thing happens, electrically speaking, with the igniter.
When you first apply voltage, the igniter is cold and the resistance is
high. When the igniter heats up, the resistance drops, and electricity is
able to flow through it more easily, and the voltage across it drops."



http://www.appliancerepair.net/oven-repair-6.html

[Phil Allison]

"Stumpy"

** The article mentions that glow bar igniters use "Carborundum".

Carborundum = Silicon Carbide = a semiconductor !!!

Like most semiconductors, it has a NEGATIVE temperature co-efficient.

So, when AC power is applied the igniter heats and draws more and more
current as it reaches a yellow glow - the current is then high enough to
operate a solenoid valve to turn on the gas.

Whoooop !!

The gas flame also heats the igniter and it stays at a low resistance value
till you turn the oven off.

However, the gas flame eats away at the material and after maybe hundreds of
hours it becomes damaged and so the resistance goes up - whether it is hot
or cold.

When enough damage has occurred, it will no longer pass sufficient AC
current to operate the gas valve.

It still gets hot, maybe even yellow hot at some spots - but no whooop cos
there is no gas.



.... Phil

[Stumpy]

>>
>> Don't most resistance heaters increase in resistance as they heat up?
>> Maybe the igniter is not NiChrome.
>>
>> 6-4 "The same thing happens, electrically speaking, with the igniter.
>> When you first apply voltage, the igniter is cold and the resistance is
>> high. When the igniter heats up, the resistance drops, and electricity is
>> able to flow through it more easily, and the voltage across it drops."
>>
>> http://www.appliancerepair.net/oven-repair-6.html
>>
>
>
> ** The article mentions that glow bar igniters use "Carborundum".
>
> Carborundum = Silicon Carbide = a semiconductor !!!
>
> Like most semiconductors, it has a NEGATIVE temperature co-efficient.
>
> So, when AC power is applied the igniter heats and draws more and more
> current as it reaches a yellow glow - the current is then high enough to
> operate a solenoid valve to turn on the gas.
>
> Whoooop !!
>
> The gas flame also heats the igniter and it stays at a low resistance
> value till you turn the oven off.
>
> However, the gas flame eats away at the material and after maybe hundreds
> of hours it becomes damaged and so the resistance goes up - whether it
> is hot or cold.
>
> When enough damage has occurred, it will no longer pass sufficient AC
> current to operate the gas valve.
>
> It still gets hot, maybe even yellow hot at some spots - but no whooop
> cos there is no gas.
>

I've got a flat, Norton type igniter which may not be carborundum. I
thought SiC had a positive temperature co-efficient of resistance. Wasn't
on the list I looked up Well I'm not worried, Amazon has an OEM replacement
for less than $20. Looks like an easy fix even if I don't understand it.
Maybe the packaging will give a description.

[Bulkhead]

On 04/17/2013 08:52 PM, Stumpy wrote:
>
> I've got a flat, Norton type igniter which may not be carborundum. I
> thought SiC had a positive temperature co-efficient of resistance.
> Wasn't on the list I looked up Well I'm not worried, Amazon has an OEM
> replacement for less than $20. Looks like an easy fix even if I don't
> understand it.

An invisible crack will render it useless. Before installing, flex your
new one to reveal any hairline cracks. They are extremely brittle. So do
not do what I just told you to do.

[Phil Allison]

"Stumpy"

>>>
>>> http://www.appliancerepair.net/oven-repair-6.html
>
>> ** The article mentions that glow bar igniters use "Carborundum".
>>
>> Carborundum = Silicon Carbide = a semiconductor !!!
>>
>> Like most semiconductors, it has a NEGATIVE temperature co-efficient.
>>
>> So, when AC power is applied the igniter heats and draws more and more
>> current as it reaches a yellow glow - the current is then high enough to
>> operate a solenoid valve to turn on the gas.
>>
>> Whoooop !!
>>
>> The gas flame also heats the igniter and it stays at a low resistance
>> value till you turn the oven off.
>>
>> However, the gas flame eats away at the material and after maybe hundreds
>> of hours it becomes damaged and so the resistance goes up - whether it
>> is hot or cold.
>>
>> When enough damage has occurred, it will no longer pass sufficient AC
>> current to operate the gas valve.
>>
>> It still gets hot, maybe even yellow hot at some spots - but no whooop
>> cos there is no gas.
>>
>
> I've got a flat, Norton type igniter

** Same type in my Westinghouse oven.

http://i.ebayimg.com/00/s/MTEyNVgxNTAw/$(KGrHqNHJDEE-vmfnDCMBQEMWZO,M!~~60_3.JPG

> which may not be carborundum.

** It is ABSOLUTELY carborundum !!!!!!!!!

> thought SiC had a positive temperature co-efficient of resistance.

** Silicon Carbide is negative up about 800C, then goes positive.

The resistance of the igniter shown drops by a factor of 2 when heated to
red glow.

The advice in the link is all correct.

OTOH - you are an ass.



... Phil

[Stumpy]

Right - I'll definitely do that.

[Cydrome Leader]

Phil Allison <phi...@tpg.com.au> wrote:
>
> "Stumpy"
>
>>>>
>>>> http://www.appliancerepair.net/oven-repair-6.html
>>
>>> ** The article mentions that glow bar igniters use "Carborundum".
>>>
>>> Carborundum = Silicon Carbide = a semiconductor !!!
>>>
>>> Like most semiconductors, it has a NEGATIVE temperature co-efficient.
>>>
>>> So, when AC power is applied the igniter heats and draws more and more
>>> current as it reaches a yellow glow - the current is then high enough to
>>> operate a solenoid valve to turn on the gas.
>>>
>>> Whoooop !!
>>>
>>> The gas flame also heats the igniter and it stays at a low resistance
>>> value till you turn the oven off.
>>>
>>> However, the gas flame eats away at the material and after maybe hundreds
>>> of hours it becomes damaged and so the resistance goes up - whether it
>>> is hot or cold.
>>>
>>> When enough damage has occurred, it will no longer pass sufficient AC
>>> current to operate the gas valve.
>>>
>>> It still gets hot, maybe even yellow hot at some spots - but no whooop
>>> cos there is no gas.
>>>
>>
>> I've got a flat, Norton type igniter
>
> ** Same type in my Westinghouse oven.
>
> http://i.ebayimg.com/00/s/MTEyNVgxNTAw/$(KGrHqNHJDEE-vmfnDCMBQEMWZO,M!~~60_3.JPG
>
>
>> which may not be carborundum.
>
> ** It is ABSOLUTELY carborundum !!!!!!!!!

Uh no, they use silicon nitride now for some ignitors.

[Phil Allison]

"Cydrome Leader"
> Phil Allison

** So FUCKING WHAT ??????????????

This example IS made of Silicon Carbide.

So, PISS OFF fuckwit troll !!!!!!!!!



... Phil

[Cydrome Leader]

what example?

what the guy has or what's in a stock photo?

Do you clench your teeth and type really fast every time I troll you?

It's almost so easy it's getting boring.

[Phil Allison]

"Cydrome Leader"
> Phil Allison

** The OP said he had a " Frigidaire" gas oven.

Westinghouse and Frigidaire are brands owned by the same company - the
Electrolux group.

http://en.wikipedia.org/wiki/Electrolux_Group

The same igniter is fitted to Westinghouse (and other) brand ovens.

http://www.ebay.com/itm/Frigidaire-Kenmore-Tappan-Gas-Oven-Stove-Cooktop-Flat-Ignitor-Igniter-5303935066-/190698709035

And they give plenty of trouble.



... Phil

[Stumpy]

New one went in fast. Tried flexing the old, heat discolored one. It is
very stiff, tough material. Unlikely to break it unless you're trying to.