NTC

OK, you're a dumbfuck then. Was there ever any doubt?

There was no irony. His comments were as ridiculous as yours.

By claiming there was irony you proved mine.

This tempco of this heating element does not go positive. Dig, I applied the flame of a propane torch to it and the resistance just kept going down. Must have gone to 600 or 700 degrees, and this thing is only used around the boiling point of water.

Wrong again. You are now batting zero.

That's weird but I imagine the water immersion stabilizes it.

Thanks for the link. I think I might send it to the manufacturers of this crazy NTC heating element I have. They're badly in need of some enlightenment.

;-)

SiC elements are NTC at (relatively) low temperatures, such as where the OP measured them, but at more normal operating temperatures (like

Best regards, Spehro Pefhany

Well, it's actually used for heating vegetable oil. I'm involved in a bit of an argument on another forum with the users of this device. They think I'm an idiot for criticizing it. If you can believe it, this thing has sold by the thousands and apparently has many satisfied users. It's extremely well made. That's why I could heat it to such high temperatures without damage. It has a 3/8" I.D. tube with an aluminum-encased rectangular heating element attached, very pretty to look at. It is called the "Vegtherm," maybe google would turn up the commercial website with a photo, but I have no stomach for looking up their website at this point.

Anyway, during use the veg oil flows through the tube and you put 12 volts on the heating element. The oil is usually preheated, and presumably the user has enough sense to operate the heater with a relay so that it turns off at the same time the vegoil valve turns off. Between the preheating and the constant flow, the NTC doesn't present any insurmountable problems. It's just a REALLY STUPID idea, when a flat or PTC heating element would work soooo much better.

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So maybe they used SiC. It's totally credible. Unforturnately, normal op for this is on the order of 200 F.

This page shows a 20 amp and a 30 amp version:

Agreed. But I think your concept of sensing the element temperature is a good one, at least as an over temperature control at zero oil flow. I would sense the outflowing oil temperature as the primary control.

Nope. You're the crazy drunk that wandered onto the field. Being struck in the head by a foul ball does not make you a pitcher.

It's hard to imagine why you would want less heat when it is freezing than on a hot summer's day.