Question on Reostat Controls

[TheJackRabbit]

I hope there is an electrician or engineer out there. Concerning a reostat type control on a 120 volt circuit for a 1,500 watt appliance. Now, as I understand it, reostats generate heat through resistance as the power output (Watts) is reduced. Over time, this heat degrades the resostat and eventually they wear out. So, my question is this: Which type of control for this circuit would last longer (a) infinite setting, (b) six fixed settings, (c) they would last about the same amount of time given everything else being equal.

Thanks in advance for the information.

 

[Pin_Head]

Rheostats generate heat dependening on the amount of power (volts times amps) flowing through them. The higher the resistance, the lower the current. You will need a big rheostat to control a 1/5 Kw appliance. Rheostats are built to take the heat.

 

[MOfj40]

They should last about the same all else equal. That is going to be one hefty rheostat.

 

[TheJackRabbit]

So, are you both saying the amount of heat produced by the reostat would be the same for both the infinite setting unit and the six fixed point setting assuming they are set at about the same level of resistance?

I am asking also becuase the six setting control unit is in a larger metal box with larger cooling vents. I was thinking of adding a cooling fan to the box.

 

[MOfj40]

it's just a variable resistor in series with the appliance. At same settings, heat output from the resistors would be comparable.

The bigger question is, why do you need rheostat control rated for 1500 watts?

 

[TheJackRabbit]

it's just a variable resistor in series with the appliance. At same settings, heat output from the resistors would be comparable.

The bigger question is, why do you need rheostat control rated for 1500 watts?

To run a 1,500 watt single burner hotplate. IS there an alternative method of controlling current to the cal-rod for heat ouptut?

 

[MOfj40]

there are alternative methods, but not cheaper/simpler methods.