Power Window Motor?

[RossL]

I installed power windows in my 55 (converted to 12 volts). I bought a set of used Ford regulators, motors, wiring harnesses and switches.

The parts were not exclusively from a 55. I can tell the wiring harness was from a late 56/57 because the wires to the switches had spade connectors, not the bullet connectors that come on the 55 switches.

How can I tell if I have 6V or 12 V motors?

I've read the 6 volt motors may operate too fast at 12 volts and this could be a problem.

[MarkR]

There’s no real problem with 6v PW motors operating on 12v. It’s just faster. Hardly anyone switches them out during a conversion. If you have your doors apart for another reason like a total restoration and don’t mind spending the money then maybe you’ll want to make the switch. Otherwise, no.

[ward 57]

Good question but I have read several posts that the 6v motors will work on 12v but are fast so just be careful at the end of their travel so you don't bend or break something. If the harness is authentic 12v I think the motors will probably be the correct ones also.

[55blacktie]

If running 6v motors on 12v, I strongly recommend that you warn passengers to allow you to control the windows. My 55, converted to 12v, still has 6v window & seat motors.

[RossL]

Good question but I have read several posts that the 6v motors will work on 12v but are fast so just be careful at the end of their travel so you don't bend or break something.

That’s what I am concerned about

[ward 57]

If they are 12v motors you have nothing to worry about. They still used bullet connectors on the motors but spade connectors on the switches. I just wonder why somebody would sell the works in the first place? Parting out the car?

[MarkR]

I would be more concerned about your heater motor. PW are momentary use so you just get use to letting up on the switch near top and bottom.
The heater motor is left on for long periods and gets very very hot on 12v. On my car even the heater harness under the dash got too hot. I didn’t use it much here and then just for a minute or two but did finally switch the motor and ordered a new harness. Mine was still original so a new switch was in order anyway. In theory 6v systems are supposed to be more than adequate for the 12v but on my car the heater motor getting that hot had me worried.

[paul2748]

On things like heater motors and window motors it's not the voltage that is the problem it's the speed that that these will operate on with 12 volts. They were not designed to run that fast so you get heat build up causing failure or worse. Window motors are not that much of a problem (as are seat motors) because they only operate for a short time (usually) as was mentioned before. Fan motors are different as they may operate for a longer periods of time and you get the heat buildup. You can get into other problems with window motors or the mechanism when they stop more harshly than they were designed for.

Generally, items such as wiring in a 6 to 12V conversion is not a problem (assuming the wire is in adequate condition) because the wire is heavier to take the amperage in a 6 volt system - less amperage is used for accessories in a 12 V system.

[klogsdonjr]

Side note - the biggest intermittent issues I had with 56 power windows (intermittent stopping at the top, wouldn't come back down, slowness) all went away when I changed from generator to alternator.

[RossL]

I changed the blower motor. I’m not concerned about damaging the motors. My real concern is if the windows are moving too fast I don’t want to damage the doors or the glass

At the moment one of my doors is in the body shop to repair a stress crack in the area close to the front chrome track for the window

[MarkR]

That’s a fairly common occurrence with the early bird door design. I think metal fatigue in that area is from repeatedly slamming the door over time to latch it rather than properly adjusting the hinges and latch. Could also be caused by the top of the door glass forward pillar being adjusted too tightly towards the windshield header causing it to bind on the door top edge.

[55blacktie]

Although I appreciate your concern about possible damage to your car, I would be more concerned about possible injury to an unsuspecting passenger.

[Rusty57]

The discussion about motor speed and overheating when sending 12 volts to a 6 volt device is simple physics. Ohms law defines the relationship among voltage, current, and resistance.

When 12 volts is connected to a 6 volt device twice the current is going to the device such as a light bulb or motor. Even more important is that 4 times the energy (power or watts) is going to the device.

For example, a 60 watt high beam headlamp in a 6 volt system requires 10 amps of current. The resistance of that headlamp is 0.6 ohms. So that same headlamp will get 20 amps of current when it is powered with 12 volts. Even more important is that there are 240 watts of energy at the headlamp. That is why a 6 volt bulb burns out so quickly when powered by 12 volts. Or the motor runs so fast!

Devices with higher inductive loads like motors, ignition coils, and horns can tolerate the higher voltage for short periods of time. Longer term they will overheat and fail. This is the situation Mark was describing with the blower motor.

Looking at Ohms law from a different direction explains why 12 volt systems were introduced. That 60 watt headlamp only requires 5 amps of current at 12 volts. So smaller diameter wiring can be used. However, that 12 volt headlamp has a much higher resistance of 2.4 ohms. If you have ever powered a 12 volt bulb with 6 volts it will be really dim. it is only operating at 15 watts!

Class dismissed!