Bench testing convertible top motor

Merc Cruzer

Merc Cruzer

Well-known member
Could anyone help me with bench testing a 4 wire convertible top motor for my 1953 Mercury Convertible. I have attached a few pictures to identify the wires, hopefully the colors of the wires are distinguishable. I want to figure which combination of wires to attache to the 6 volt battery without the use of the relay. The color of the wires: the two on the left are white or possibly yellow, the second from the right appears to be black and white and the one on the right is green.

Thank you for you assistance.
 

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Puzzling as the schematic seems to show only 3 wires to the motor.
Suspect that the green loop end wire is the motor ground and the black one is the relay ground.
The other two are either up or down wires.
See if there is continuity between the motor ground and the relay ground.
If so then contact between the motor ground and either of the two remaining wires should give motor action.
 

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51 MERC-CT

It appears that the Mercury/Lincoln motor has three wires but the same motor use in the same year Ford had 4 wires
 

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Upon further testing it appears that I have continuity between the two outside wires and the second test I have continuity between the two inside wires. It would be my guess that the wire with the round grommet would be the ground for the relay. I would also guess the the two wires on the left in the picture would be the forward and reverse. Still trying to figure out which wires go to the pos and neg terminals of the battery. Do I need to pair up the black wire with the green wires (assuming they are both grounds) and attache them to the pos post of the battery and then touch one of the other wires to the neg post for the test. I would then change the directional wires for testing for forward and reverse. Let me know if this seems correct as I do not want to short out the motor, they are too hard to find and too expensive to repair. Thank you for your assistance.
 
I think you will find the wire with eye is ground the red is power the middle ones are up and down.dont forget that you have positive ground.so it will appear backwards as to the ground being positive.yellow and green are up and down.hope this makes sense
 
There are several possible configurations of circuits for reversible motors. Polarity can be reversed on some (modern transistorized control) and many older ones have separate windings for one direction and the other. They can sometimes share a common ground and sometimes not depending on the components they use to build the circuit. A lot depends on how much torque they were designed to put out too. A person really needs a good diagram for what conductor wires are intended to do (wire color codes) and a good understanding of how the control relay is supposed to function. I figure the two circuits have to be isolated from each other for one to work without affecting the other.
 
Merc Cruzer said:
Upon further testing it appears that I have continuity between the two outside wires and the second test I have continuity between the two inside wires. It would be my guess that the wire with the round grommet would be the ground for the relay. I would also guess the the two wires on the left in the picture would be the forward and reverse. Still trying to figure out which wires go to the pos and neg terminals of the battery. Do I need to pair up the black wire with the green wires (assuming they are both grounds) and attache them to the pos post of the battery and then touch one of the other wires to the neg post for the test. I would then change the directional wires for testing for forward and reverse. Let me know if this seems correct as I do not want to short out the motor, they are too hard to find and too expensive to repair. Thank you for your assistance.
Click to expand...

Try momentarily connecting ground + (without pairing any wires) to either of the two outer wires.
 

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The diagram has part of it cut off that can't be seen. Ford used yellow coded conductors for power and you can see that in the diagram from the circuit breaker. The green wire from the motor with the ring terminal wire is likely the ground for the whole unit. It should have continuity from the ring terminal to the body of the motor unless it is isolated. The black, yellow, and red conductor wires from the motor with the U terminals appear to be the control wires. I'd sure like to know how that relay switches the contacts.
 
I can verify that none of the wires have continuity to the body of the motor. FYI, this is an original convertible top motor form 1953.
 
54vicky said:
I think you will find the wire with eye is ground the red is power the middle ones are up and down.dont forget that you have positive ground.so it will appear backwards as to the ground being positive.yellow and green are up and down.hope this makes sense
Click to expand...


Just make sure we are on the same page:
Wire with the round eye goes to the + side of the battery (pos ground)
Red wire for to the (-) side of the battery
Then the yellow or green wire then goes to what side of the battery?
 
With green wire hooked to + ground.
Touch red wire only with neg bat. Motor should turn.
Remove red wire and touch yellow wire only to neg. bat. Motor should turn in opposite direction.
 
51 MERC-CT said:
With green wire hooked to + ground.
Touch red wire only with neg bat. Motor should turn.
Remove red wire and touch yellow wire only to neg. bat. Motor should turn in opposite direction.
Click to expand...


The issue is that in reality there are no red and yellow wires, only two off white wires, a black wire and green wire, so they do not match the color coding on the diagrams. With that being said I connected the wire with the round grommet to the (+) ground and then separately touched each of the two off- white wires to the (-) Neg post. One sparked but the motor did not run and the other resulted in nothing at all.
 
Merc Cruzer said:
The issue is that in reality there are no red and yellow wires, only two off white wires, a black wire and green wire, so they do not match the color coding on the diagrams. With that being said I connected the wire with the round grommet to the (+) ground and then separately touched each of the two off- white wires to the (-) Neg post. One sparked but the motor did not run and the other resulted in nothing at all.
Click to expand...
Did you try the remaining wire?
 
Rather than wondering, it was time to take it apart to see just where each wire went. Sometimes you need to look into the belly of the beast.

From the original picture with the motor and wires:

The wire with the round grommet (green) goes to the left side of the field winding.

The off white wire (second from the left) goes to the left brush

The black wire (third from the left) goes to the right brush

The off white wire (on the far left) goes to the right field winding.

Hope this helps, and thanks again for all of your assistance. Any tests while it is apart?
 

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Try this. Take the two armature wires and make one positive and one negative. Do the same with the two field wires. This should make it turn in one direction. Reverse the +/- on the field and it should spin the opposite. If you're worried about burning something up then throw a 20 amp cb in the circuit. There is no load so this should spin easily on 20 amps.
 
Frank Miller said:
Try this. Take the two armature wires and make one positive and one negative. Do the same with the two field wires. This should make it turn in one direction. Reverse the +/- on the field and it should spin the opposite. If you're worried about burning something up then throw a 20 amp cb in the circuit. There is no load so this should spin easily on 20 amps.
Click to expand...

Frank,

Worked perfectly. Since basically you are creating two dead shorts on the battery the wires got hot quickly. But I was able to test in both directions by switching the field wires. I am now wondering if the relay controls the amperage, otherwise the wires would be fired by simply putting the top up or down.

Could this motor be converted into a 3 wire motor?

Thanks again,

Roy (Merc Cruzer)
 
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