• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

DC Auto Windshield Wiper Motor Help!

RogerB

New Member
Guys & Gals,

I have a project to use a windshield wiper motor to drive a mini mill power feed. I converted a computer power supply for the juice and purchased speed direction control unit on eBay. I tested the electronics using a auto electric window motor and all worked as it should. I didn't have connections for the wiper motor at the time, but I did verify that at worked good.

So, now I have the project together, but the motor does not work as expected. It runs at a constant speed, doesn't slow down when I turn the speed controller down. When I turn the speed controller to stop and then reverse, the motor does not turn at all. I connected up the power window motor again and it works as it should; changes speed and direction of rotation.

I'm thinking the wiper motor is good, but has electronics that make it behave differently. So, my question is can I do something relatively simple to the electronics to get this motor to respond as needed? If so, what do I need to do?

If it can't be done with some fairly simple changes, I'll have to get another motor. I'm not doing this immediately because I have a lot of time invested in the motor coupling and mounting bracket for this motor.

Below are a few pictures of the circuitry in the motor housing.

Thanks in advance for any input.

Roger Barker




IMG_0479-800X600.JPG
WiperMotorFromVid.jpgIMG_0482-800X600.JPGIMG_0483-800X600.JPG
 

Attachments

Last edited:

ClydeCrashKop

Well-Known Member
Most Helpful Member
You could try bypassing all of their circuitry and wire directly to the brushes.
Hopefully on the circuit board.
 

rjenkinsgb

Well-Known Member
Most Helpful Member
Is it a permanent magnet motor, or wound field?

The windscreen wiper motors I've seen have been "series wound" configuration, which is good for getting the maximum torque from the motor but not good for any kind of feedback-based speed controller.

The smaller window motor was likely a permanent magnet type.

If your wiper motor does actually have a permanent magnet field, the tracing the brush connections and wiring straight to them like ClydeCrashKop says should work fine; but do not try that with a series wound motor, you are likely to destroy your speed controller.
 

RogerB

New Member
Ok, thanks guys,

I could feel very powerful magnets when pulling the housing off the armature. I see 3 brushes. So, should I run positive to all three?

Thanks again,

Roger
 

ClydeCrashKop

Well-Known Member
Most Helpful Member
If there are 2 brushes directly opposite each other, use them. Positive and negative. Swap polarity for direction.
 

alec_t

Well-Known Member
Most Helpful Member
If you tried running the motor from the controller without back-emf protection the controller may now be toast :(.
 

Visitor

Active Member
The Post Apocalyptic Inventor on YouTube has a number of videos showing how to use wiper motors. Search his channel for some proven advice.
 

rjenkinsgb

Well-Known Member
Most Helpful Member
Looking at the picture below; the four connections across the top (plug pins?), left to right, most likely configuration:

First two = fast/slow speed, either one or the other most likely.
Third = motor common (switched in the vehicle).
Fourth = permanent common, to parking position switch.

The third and fourth would be connected in any but the park position, via a rotary wiper in the gearbox.

I'd try 12V power across first & third positions & see if that runs?

 

saabnut

New Member
rjenkinsgb across the top from left wiper high, then low, or vice versa, then park circuit ( has power with wiper switch off) then ground. In the alternative far right is positive, and the others are switched to ground. Then also there is likely some intermittant function we do not need to consider.
 

rjenkinsgb

Well-Known Member
Most Helpful Member
cross the top from left wiper high, then low, or vice versa, then park circuit ( has power with wiper switch off) then ground. In the alternative far right is positive, and the others are switched to ground.
Not possible.

The three pins that link to the motor stick up at the left; connecting to 1 - 3 across the top.

The third and fourth at the top are the park switch, so cannot ever have direct power & ground across them, as they are shorted for part of each rotation.
 

RogerB

New Member
Guys,

Thank you big time! Wiring positive to one brush and negative to the brush across from the first has the motor now working as it should. Speed is variable and direction of rotation changes with the controller. It does seem to run a little slower, but that's OK for this application.

Thanks again,

Roger
 

Latest threads

EE World Online Articles

Loading

 
Top