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Windscreen wiper motor questions

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bitem2k

New Member
I recently salvaged an old windscreen wiper motor from a car.

The Motor has four terminals. Ive got two of them connected and it seems to work fine, is this right?

I intend to run the motor for hours at a time, and i would imagine that they are capable of that. I sometimes drive for hours in the rain and i would have my wipers on for the entire time.

If i run it for hours, it gets realy hot, and stays that way for about 30minutes after i turn it off. Is it meant to get that hot?

Thanks very much.
 

RODALCO

Well-Known Member
bitem2k

It shouldn't be too hot to touch.
Certainly you shouldn't burn your fingers on it.

What are you driving with it. The loading may be too heavy for the motor.

It is usually a series motor, check that the armature is in series with the field windings.
 

bitem2k

New Member
RODALCO said:
It shouldn't be too hot to touch.
Certainly you shouldn't burn your fingers on it.
Its def. hot enough to burn yourself on.

RODALCO said:
What are you driving with it. The loading may be too heavy for the motor.
It overheats with no load

RODALCO said:
It is usually a series motor, check that the armature is in series with the field windings.
Im sorry can you please explain that to me, I know nothing about motors.

thanks
 
Last edited:

Rolf

Member
Not 12V ......... ?

bitem2k said:
I recently salvaged an old windscreen wiper motor from a car.

The Motor has four terminals. Ive got two of them connected and it seems to work fine, is this right?

I intend to run the motor for hours at a time, and i would imagine that they are capable of that. I sometimes drive for hours in the rain and i would have my wipers on for the entire time.

If i run it for hours, it gets realy hot, and stays that way for about 30minutes after i turn it off. Is it meant to get that hot?

Thanks very much.
Depending on how old the car was that the wiper motor came out of, it could be a 6V motor.
 

3v0

Coop Build Coordinator
Forum Supporter
You need to figure out what each of the 4 wires do. It is possible that although you have it running it is not hooked up as intended.

When you turn a wiper motor off it runs long enough for the wipers to go back to the rest position. I think that means there is a always on wire to power the unit while it returns to the rest position. (1 wire)

In most cases there are at least two speeds. (2 wires)

Maybe a ground (1 wire)

Could also be that the motor is grounded through the case and you are using a wire for ground.

In the following page the author hooks an H-Bridge to one.

http://www.ayershome.org/~eric/robots/hbridge/index.shtml
 
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Nigel Goodwin

Super Moderator
Most Helpful Member
Wiper motors are pretty sturdy devices, they are often used in medium suzed robot project, and generally last extremely well, even when fed from 24V rather than their designed 12V. One problem with them is that they are only designed to rotate in one direction, and the brushes and bearings are designed accordingly.
 

Andy1845c

Active Member
bitem2k said:
I recently salvaged an old windscreen wiper motor from a car.
Do you know if it was working when it was in the car? They are pretty tough, like Nigel said, but if it came out of a car thats been sitting for years maybe its rusty or gummed up inside. How does it feel when you spin it by hand? smooth and free or stiff and rough?
 

bitem2k

New Member
thanks all for replies.
I took it out of my sisters car, the engine had died recently, the wipers functioned fine.

I cant really spin it by hand, its quite hard to move it. I thought that was because of some kind of internal gearbox?

The motor has a black 4 pin plug attached to it, going into this plug (from the motor) are two wires, red and yellow.

If i connect the first pin and the last pin, the motor spins quickly.

If i connect the last pin and the pin next to it, the motor turns slowly and in reverse direction.

Does this help?

thanks
 

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bitem2k

New Member
Nigel Goodwin said:
Wiper motors are pretty sturdy devices, they are often used in medium suzed robot project, and generally last extremely well, even when fed from 24V rather than their designed 12V. One problem with them is that they are only designed to rotate in one direction, and the brushes and bearings are designed accordingly.
Nigel, do you think im running it the wrong way? Would that cause enough heat to fry an egg or even a nice juicy bit of steak?
 
Last edited:

Nigel Goodwin

Super Moderator
Most Helpful Member
Yes, you can't turn it because of the internal gearbox - you should be connecting it so it runs fast, that's probably a direct connection to the motor. Usually one of the motor connections will be connected to the metal body of the motor, that should be the negative connection.
 

bitem2k

New Member
If im connecting the motor up the wrong way round, ie (+ to -) and (- to +) opposite to which manufacturer intended,
do you think that would cause the heating?

thanks
 

Nigel Goodwin

Super Moderator
Most Helpful Member
bitem2k said:
If im connecting the motor up the wrong way round, ie (+ to -) and (- to +) opposite to which manufacturer intended,
do you think that would cause the heating?
Possibly, it's only intended to turn one way, try it the other way and see if it still gets hot - but electric motors DO get hot.
 

HarveyH42

Banned
Okay, 4 wires... You have 2 speeds, there is a 'Home' sensor so it doesn't stop in the middle of the windshield (windscreen), not sure if its one or two wires, almost all automotive ground to chasis. The gearhead in the one I took apart many years ago had a worm gear, so gotta go with the on direction deal. Put (-) to the case, and 2 of the 4 wires should make it go...

Since it got hot enough to mention, guessing very hot. I'd open the gear head and see if there is damage, and just to make sure its well greased after the melt. Makes a big difference...
 

arunb

Member
Wiper motors do get hot after continuously running for quite some time. In fact many of them do get burnt out, they do not burn as often in a car because I think they are well ventilated and also because they come in use only during the rains....just a guess

thanks
arun
 

RODALCO

Well-Known Member
Years ago i used to drive an old DAF tip truck for the council.
That was a vintage 1950's DAF.

That truck had two wipermotors which were mounted on the windscreen, shaft drilled through the windscreen and an on off switch at the back of the motor.

These were 12 Volts Bosh motors. After long running the motors were warmish to the touch but definitely not hot.

As said, check that the armature is not binding or the gearing grease hasn't dried up to a gummy gunk.
 

Rolf

Member
... abuse

arunb said:
{snip} In fact many of them do get burnt out, they do not burn as often in a car because I think they are well ventilated and also because they come in use only during the rains....just a guess

thanks
arun
So where do all these motors get burned out?
Must be from abuse because my wife and I have been driving (mostly older cars) for over 50 years and we have newer had to replace one.
I think that is an indication that they are pretty reliable.
 

HarveyH42

Banned
I drive cheap used cars myself, just basic transportation. I don't travel much beyond what I have to, so don't need something fancy. Rather spend the money on other things I would enjoy more.

Most everything I've owned has been in the 14-20+ age, and never had a bad wiper motor. I have had to wire up some new switches to replace broken ones on the column though.

The gearhead is packed with grease. The one I took apart had a worm gear. The cover is just a few screws, pretty easy to open. I would definately check the lubrication, as this is most likely to be the problem. Grease ages, heat destoys it, if the seals fail can leak out. The motor and gears are very solid metal, should be tough to kill.
 
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