UKC

Can people with electrical experience chip in on this please.

I want to control the temp of an electrical branding iron. I.e. be able to set a temp and the iron switch automatically to stay at that temp. (Some fluctuation is fine within a few tens of degrees) my ideal temp would be around 250 degrees C

The iron is essentially a small 2 bar electric fire that heats the back of a steel plate to which the die is fastened.

I was thinking this sort of thing would work. I could fasten the probe to the iron somewhere suitable

http://www.euroheat.co.uk/ImgShare/2097011638Flue%20Thermostat.pdf

...Except that is does the switching in the opposite way. Can I easily change the way it switches? A relay of some sort?

I want the circuit to be on (heating) until set temp is reached. Then to switch off until temp drops below the threshold and switch back on again. I'll get some sinusoidal temp regulation but that's fine.

Is there a better way?

Sorry about long winded post.

In reply to George Fisher:

Unless I'm reading it wrong, the unit in your link provides changeover switching. It says "p - 2 is closed when the actual temperature exceeds the set temp". I would think that p - 1 is closed when the actual temperature does not exceed the set temperature, which is what you want. A quick call or email to the manufacturer would confirm this (or not).

Apart from that, I've no idea whether this unit would be suitable for what you want.

In reply to George Fisher:

Fleabay item: KSD301 N/C THERMOSTATE

OPERATING TEMP: 250C

CONTACTS: NORMALLY CLOSED

AUTOMATIC RESET

VOLTAGE: 250V

CURRENT: 10A

Would do the job I think, heating element normally on, cuts out when temp reaches 250.
Have used similar to control fan on radiator.

In reply to George Fisher:
You are ideally going to need a bit of hysteris in the loop - I assume the thermostat provides for this?
Does it need really need to be closed loop i.e. is there substantial thermal load when doing the branding? If not you could just use a variac to reduce supply voltage to the element and do a one off calibration with a temperature probe to obtain a fixed 250 deg C operating point.