heater resistor..

[beastm35]

I have a question on the incab heater. why does the resistor get very hot when the fan is on low but works fine on hi? could it be the blower motor is bad?Thanks

 

[cattlerepairman]

A resistor converts electrical energy into heat. That is how they work. The electricity not convereted into heat ("the rest") gets to run the fan motor and it is enough to turn it at low speed. For high speed, the fan motor requires all the electrical energy, so the resistor is not being used.
I am sure there is a more elegant, electrotechnically more accurate explanation.

 

[rustystud]

A resistor converts electrical energy into heat. That is how they work. The electricity not convereted into heat ("the rest") gets to run the fan motor and it is enough to turn it at low speed. For high speed, the fan motor requires all the electrical energy, so the resistor is not being used.
I am sure there is a more elegant, electrotechnically more accurate explanation.

No, you basically covered it very well ! I took electrical engineering for two years (mostly math and more math !) and their explanations could be so complicated for such simple concepts.

 

[beastm35]

A resistor converts electrical energy into heat. That is how they work. The electricity not convereted into heat ("the rest") gets to run the fan motor and it is enough to turn it at low speed. For high speed, the fan motor requires all the electrical energy, so the resistor is not being used.
I am sure there is a more elegant, electrotechnically more accurate explanation.

thanks for your help but when I say the resistor is hot it will melt plastic..I should have explained that better that's why I was asking..

 

[doghead]

It should not touch anything. It needs the air around it to cool it.

It should be a 50 watt resistor, if I recall correctly. It could be as much as 100 watt.

Think about the heat a lightbulb gives off. Can't touch them either.