The Stovebolt Site Forums The Shop Area The Electrical Bay Voltage Reducer can grill burgers?

You shoulda seen the looks shot at me last night on the way home from dinner when the temp was 40 degrees and the heater not working. The other half won't ride anymore without a heater, so I tried hooking it up today, using the heavy duty voltage reducer from our sponsor, ATCP. How hot is the reducer supposed to get? I could barely touch it, no way to hold it-really, really hot. Where to mount it if it gets that hot? It's about the size of a roll of dimes, 3 inches long, a tab at both ends for the wires. Just for fun, I tried just for a second running it without the reducer...wow...gotta clean all the dust-looked like a sandblaster going off. Wife would have been warm all right. Don't know if it makes a diiference, but I tried running it off the battery directly, no fuse or anything, and the truck is 12 volt neg. Anybody know of any good articles about the original heaters? I got the accesory install manual, but it's only so-so. Please help! Mean wife!

Tell your wife that heat isn't everything, and or next time get a steel bucket and drop some hot coals in it for the ride home.

my voltage reducer gets that hot. I mounted it on the inside the end of heater. right where it blows into the cab. That way, the "heated air" would cool it down, and also, nothing flamable close :p .

Brian K

I made a metal bracket for mine and mounted it behind the radio grill on the lip on the bottom of the dash. It is up out of the way, is not touching anything. Seems to work okay there.

I do like the idea of mounting inside the heater.
:rolleyes:

My aftermarket Sears Allstate heater (1949 period piece) had a 6V motor. I replaced it with a 12V motor and did away with the V reducer, fan flies, no worries. Do a search for 'fan motor', I bought it from a website found here.

I'll second the idea of a new 12 volt heater motor. I bought one at the parts store. It looked exactly like the 6 volt motor. Bolted right in. Works fine.

Because the voltage reducer is cutting the voltage in half by being in series with the fan motor, it has to waste the same amount of power that the fan motor draws, which is a lot.

Another option is to use two of the resistors and wire them in parallel. It doesn't lower the voltage as much, but it also doesn't get nearly as hot.

Wiring the resistors in parallel will reduce the effective resistance to half(assuming both resistors have the same resistance). As you said this means the voltage to the fan motor will be higher. You run the risk of it being too high and damaging the motor.

If heat is an issue:
1. Get a resistor of the same resistance, but one designed to dissapate more wattage (heat), or:
2. a. Get four of the resistors you now have
b. Make two sets of two resistors wired in
series
c. Take the two sets of series resistors (2 in
each series) and wire them in parallel.
You will end up with the same effective resistance as one resistor, but with heat dissapation distributed among four resistors instead of one.

But you will still be wasting all that energy into the cab. I like to use my fan for ventilation sometimes (fresh air heater). A 12V motor is the way to go.

You can get a universal replacement motor for about $25. Using large resistors is very poor practice. If you are he** bent on using a resistor for dropping voltage: Use a resistor rated for at least double the actual dissipation. I really like the aluminum housed wirewounds since I can mount them to a heat sink. But in the end you will have spent enough to replace the motor!!!

When Mrs. Wally and I were both 17 years and "parking" in my light green '51 Chevy DeLuxe near the local cemetery in 1962 or so, we both noticed a hot smell under the dash. The cig lighter had shorted. I pulled out the wire and got a lot of sympathy for my burns. It has nothing to do with a hot voltage reducer but your question has made us smile about our youth.

(Note: This post has been approved by Mrs. Wally.)

Wally,, was that wired in on purpose :p :p (i thought you knew easier ways to get sypathy)

I dunno what kinda truck you have but the AD fresh air heater fan motor in 12 volt guise is available from Grainger Inc. - I found the P/N in an old post and bought one for cheap .

Conversely the dropping resistors for the three speed fans on GM products on the 60's were always
mounted in the defroster duct so there'd be some airflow any time the motor was run .

Better fix this PDQ ~ winter is about here and SWMBO must be appeased ! .

Care to repeat the part # Nate? I need one or two of those motors.

Sadly , I don't have it ~! I got it here from an older post , ordered it and ripped the package to sh*t removing it to see if it was really the correct one , in my excitement I destroyed the part number info , I'm sure if you can search rhe archives this is in there somewheres .

Search heater of fan motor , like that - it never works for me but I'm told it does work .

I'll look for it too (Grainger part #), although I have an old Sears Allstate circa'50's heater I used the same 12V motor, runs like a Deere!

I am pretty sure the one at the bottom of this page is it.

Ken, your link took me to a blank page. 12 volt motor
Part # 2M197

So that 12 volt motor from Grainger will fit right in to the heater on the AD trucks? Or is there some 'engineering' involved?

-W

Fred,

You have to have adobe acrobat and scripting enabled on your browser and it pulls up the sheet of interest.

Wooger . . . that motor is a bolt in and should not require any mods.

Does Grainger still require you to have a commercial account with them or can you walk into their store and pay cash?