amps for defroster motors

[robertglines1]

How many amps at 24 volts will each pull? reason I ask when I installed the Cole Hersee 24 volt defroster(68366) switch it got hot right away. I stopped there! I did not have a previous switch when I purchased the 98 Prevost salvage shell. Want to make sure the next one will do the job.  Do the switches vary voltage to control speed?    range?  I have a assumption but have no faith in my self on this subject.   Bob

[Darkspeed]

That looks like a three tap resistor on the output side for multiple speeds? If it was over loaded it would get VERY hot.

Ok found specs it is a 6 ohm @12v 3 ohm @ 24v variable low-med-hi

[bevans6]

Not to say yours is like this, but my MCI defroster is wired in what I thought was an interesting way.  Two motors, and they are wired in series (half voltage) for low speed and in parallel (full voltage) for high speed.  That means you don't need a rheostat to change the speed.  I always thought dumping half the power into heating up a resistor was a dumb idea anyway.

Brian

[robertglines1]

follow up. went 12 V thru the cole heerse =same result.  Then went 12 volt power via relay to each fan= good speed. did 24 volt same set up= to much out put in my mind.  The 12V set up puts out good flow for 8 outlets.   Bob

[chessie4905]

Gm defroster motors do it the same way.The 4905 defrostermotorsare rated at 3.5 amps@24 volts.