I am totally green with wiring and electrical stuff. But I need help identifying a part and have other questions if someone has the time to humor me.

 

I am totally green with wiring and electrical stuff. But I need help identifying a part and have other questions if someone has the time to humor me.

HCET VA1 VAA1 creep action Electric iron bi-metal Temperature protector, thermostat switch for heating pad.
75°C.
https://www.alibaba.com/product-detail/Electric-iron-bi-metal-thermostat-switch_60736995661.html

 

HCET VA1 VAA1 creep action Electric iron bi-metal Temperature protector, thermostat switch for heating pad.
75°C.
https://www.alibaba.com/product-detail/Electric-iron-bi-metal-thermostat-switch_60736995661.html
View attachment 290961

Thanks! What is its purpose? Ok so I basically dissected a heating pad because I wanted to make a smaller one. But I only really know that if I shorten the wire that heats up I might mess up the whole pad and it could catch fire.

 

Welcome to AAC. Nice to have you join us.

The device is a TCO (Thermal CutOut) it is a safety device to prevent overheating. It has a bimetal spring arm inside that warps when it is heated. If it gets too hot it flexes suddenly snapping out of contact and switching off the heater.

After it cools, it eventually snaps back into contact and the heater is reconnected. It has to be in intimate contact with the heater to work properly.

As far as modifying the pad, this is a bad idea. Very bad. Very dangerous. You are correct that shortening the heater wire will cause it to get hotter. This is because the heat is proportional to the electrical resistance of the wire, and the resistance is proportional to the length.

The lower resistance of the shortened wire will increase the current and so the heat. If you need a smaller heater, you need a different wire that has a resistance compatible with the intended length.

Could you describe what you are trying to accomplish? There‘s certainly a chance that some way other than cannibalizing a larger pad will get you what you want.

How will the pad be used?
What is the voltage you are using?
How big does the pad need to be?
Have you tried to find one already properly sized?

 

Welcome to AAC. Nice to have you join us.

The device is a TCO (Thermal CutOut) it is a safety device to prevent overheating. It has a bimetal spring arm inside that warps when it is heated. If it gets too hot it flexes suddenly snapping out of contact and switching off the heater.

After it cools, it eventually snaps back into contact and the heater is reconnected. It has to be in intimate contact with the heater to work properly.

As far as modifying the pad, this is a bad idea. Very bad. Very dangerous. You are correct that shortening the heater wire will cause it to get hotter. This is because the heat is proportional to the electrical resistance of the wire, and the resistance is proportional to the length.

The lower resistance of the shortened wire will increase the current and so the heat. If you need a smaller heater, you need a different wire that has a resistance compatible with the intended length.

Could you describe what you are trying to accomplish? There‘s certainly a chance that some way other than cannibalizing a larger pad will get you what you want.

How will the pad be used?
What is the voltage you are using?
How big does the pad need to be?
Have you tried to find one already properly sized?

Thank you so much for the reply. I’m so sorry I haven’t responded sooner. I wanted a smaller sized heating pad and haven’t found anything on the market to suit my needs. So since the length of the wire is shorter does that mean I should get a thicker gauge wire? How do I figure out the voltage that I’d be using? Thank you so much for your help.

 

Welcome to AAC. Nice to have you join us.

The device is a TCO (Thermal CutOut) it is a safety device to prevent overheating. It has a bimetal spring arm inside that warps when it is heated. If it gets too hot it flexes suddenly snapping out of contact and switching off the heater.

After it cools, it eventually snaps back into contact and the heater is reconnected. It has to be in intimate contact with the heater to work properly.

As far as modifying the pad, this is a bad idea. Very bad. Very dangerous. You are correct that shortening the heater wire will cause it to get hotter. This is because the heat is proportional to the electrical resistance of the wire, and the resistance is proportional to the length.

The lower resistance of the shortened wire will increase the current and so the heat. If you need a smaller heater, you need a different wire that has a resistance compatible with the intended length.

Could you describe what you are trying to accomplish? There‘s certainly a chance that some way other than cannibalizing a larger pad will get you what you want.

How will the pad be used?
What is the voltage you are using?
How big does the pad need to be?
Have you tried to find one already properly sized?

Also, is there a formula to calculate the wire length and resistance to create a small heating pad?