Voltage Reducers For Heater/Blower Fans

[55 Fargo]

Hi all, installed a heater box , it has a 6 volt fan, spins like a MF, on a 12 volt diet, any sggestion for a 12-6 volt reducer, I should be using. My Heater switch, appears to be 2 speed, and too much voltage going through on low speed. Any idea, how much volatge beyond 6 an old Mopar 6 volt heater motor can tolerate???

[mochevy69]

I got one from J C Whitney years ago. They may still carry them.

[wldavis3]

MF = "modified flathead"???

[deathbound]

Here's one on ebay, just for reference:http://www.ebay.com/itm/290600767031?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

[Plymouthy Adams]

now everyone knows that when Fred put MF on there he was referring to Massy Ferguson..Fred..this this is not revelation, been covered many times..get your dropping resistor and I assure you the sun will rise in the east.

see post number 9...

http://www430.pair.com/p15d24/mopar_forum/showthread.php?t=6616&highlight=runtz+reducer

Edited December 19, 2011 by Tim Adams

[oldmopar]

In the referenced old posting there was talk of the heat generated. The link below is a high priced reducer and i am not recommending that only showing how large a heat sink is used by a manufacture for this application.

http://www.ronfrancis.com/prodinfo.asp?number=VR%2D4

[Robert Horne]

During the summer, I installed my original heater in my 38.

I used a ceramic type 12 to 6 volt reducer, I bought on ebay years

ago. It works very good. My 6 volt fan only has one speed,

is quiet.

[Young Ed]

Fred heater motors are fairly generic so I'd be looking for a 12v motor to swap in.

[greg g]

would a ballast resister work??

[Plymouthy Adams]

Greg..the resistor has to be rated in the correct wattage to prevent burn out and displace the heat..say for instance the motor pulls some 6 amps on 6 volt..then pulls some10 amps on 12 then the three amps of power must be replaced..4 extra amps at 12 volts will be 48 watts of power..you will wnt a buffer there..you wil find that mounting these on a stock of aluminum in a place that the aluminum surface can also absorb heat from the resistor and displace the heat easily into the atmosphere..a heat sinking compound will be benefical here also..

[Adam H P15 D30]

I agree to swap to a 12v motor. A lot less heat in the circuit and easily found. I used one I had lying around from a Dart?? I think. Shaft was slightly shorter but the set screw still caught it. I also heard some 70's Dodge van motors work too but not sure. This was on my 49.

[55 Fargo]

If this were an everyday vehicle, I would definately witch to a 12 volt fan motor. But for occasional use, and most in the summer months, am going to try this, a voltage reducer designed for blower motors...

http://www.speedwaymotors.com/Electric-12-Volt-to-6-Volt-Reducer-for-Motors,15824.html?

[BeBop138]

I used one ohm 50 watt power resistors---cheap at the electronic surplus houses---put it between the switch and blower motor. A .5 ohm could work also with a two speed----just hook it up and test for voltage and use the one that works the best..........Lee

[55 Fargo]

I used one ohm 50 watt power resistors---cheap at the electronic surplus houses---put it between the switch and blower motor. A .5 ohm could work also with a two speed----just hook it up and test for voltage and use the one that works the best..........Lee

Thanx Lee, sure is an economical way to go, sure it would meet my needs.....thanx...

[55 Fargo]

Just did some testing with the heater fan motor. On high speed, 11.2 volts were going through, on low speed 6 volts were going through the heater switch.

The heater fan control switch would get red hot, right quick, indicating far too much amperage draw with a 6 volt motor, being fed a 12 volt diet.

I think, have a problem, have not got a voltage reducer yet, quite possible I may need to convert this heater to a 12 volt motor, and save some problems.

[Plymouthy Adams]

you don't have a problem..what you have is that you are not following the words of widsom place before you in answer to your earlier question..all this has been explained..either get a reducer or go to 12 volt motor..if you wish to continue playing there is one thing left to work out..measuring the resistance of the motor and using this value and the known volatge you just took with the meter it would then tell you your exact wattage pull and with that you can get the correct ohm rating resistor of the correct wattage.....

[Robert Horne]

There is a heater fan reducer on ebay, about $20 delivered....

10 AMP.. 12 volt to 6 volt.........

[knighthawk]

Rocky......listen to Tim ....as in his first post ! You know him well enough to know that what he says, although it is sometimes hard to follow, he is very seldom, if ever, wrong, especally with the electrical stuff !

[55 Fargo]

Tim, is bang on, really knows his stuff, and I do not 2nd guess what he is saying, sometime the interpretation from my end might be off.....LOL. I am waiting on a 50 watt 10 amp ceramic voltage reducer, built for blower motors.

Once I get it, will post the data.

It was relatively cheap, at $30.00 here in Canada, it is already at the parts store waitng for me to pick it up, after the holidays...Thanx you all, and have a Very Merry Christmas....

[Oldguy48]

If you can mount that voltage reducer into the airflow path of the heater, maybe you can recover some of the heat lost in reducing the voltage.

[55 Fargo]

Okay here is what I ended up creating to reduce the voltage from 12 to 6 for the heater blower motor.

I ordered on-line a 50 watt1 Ohm resistor, for $4.00, then made a mount employing a 4.5 inch long 1/4 inch bolt/nut, mounted on 1/2 aluminum, this is spaced from the firewall by 1/2 inch, and bolts on from under the hood.

Tim Adams suggested mounting it somehow in the deforst tubes, prior to the hoses going out to defrost vents, this idea is excellent, but have not figured out how I may do that yet.

I took the truck for spin, heat on, cold day today, resistor got good and warm, but not burning up, the variable heater switch and lead wires stayed cool.

The truck cab was toasty warm. I still need to wire in prior to the switch an inline fuse, and think 10 amp fuse should be the higheest I should use.....

[48mirage]

http://koolcars.us/catalog.html

[55 Fargo]

http://koolcars.us/catalog.html

I would simply buy a 12 volt motor in my case. I think these are well made units, but maybe overkill for what I need.

I actually know a few Guys who do not reduce the voltage to their 6 volt heater motors, they just use the speed control switch, and they are'nt used all that much.

This little voltage dropper I made up, is working quite well...... and it was $4.00

[Paul Hoffmeyer]

I have one of those koolcars voltage regulators on my '45 Dodge pickup street rod to run the 6 volt wiper motors. Good product and good service, also.

Paul H

[55 Fargo]

I wired in an in-line fuse, and used a 10 amp fuse. This is working great, so do not think I am drawing huge amounts of current. This little resistor is cheap compared to more Heavy Duty units aformentioned, but if I need to go that route, will just buy a 12 volt motor and be done with it