bad wiper motor

[fordman]

i was testing a wiper motor this morning and relized it didnt have high speed. it wasnt the switch becasue io used three different switches with the same motor. i went out and got another one to ship.

but anyway. what inside of the motor could have went wrong? could it just be a bad connection inside the motor that i can fix?

[basketcase0302]

TF or someone else can probably explain it better...
I've seen A/C (not D/C) motors losing partial windings do this, (I'd guess our D/C motors aren't much different in the symptons).
You'd still have some speed or part of the motor work.

[Thunderfoot]

It could have broken the wire connection to the High-Speed windings inside the motor, or they might have died. There are 2 sets of windings in the motor one set for Slow speed and one set for the High speed...

[Thunderfoot]

I've seen A/C (not D/C) motors losing partial windings do this, (I'd guess our D/C motors aren't much different in the symptoms).
You'd still have some speed or part of the motor work.

Yes, this happens in DC motors as well, I have had it happen on my electric water pump motors I run on my race car... but the wiper motor has two separate windings in it for the 2 speeds.

[fordman]

i took it apart and couldn't see anything to fix so it is a dead motor as far as i am concered. it will only be used for testing or scrap metal weight soon.

[fordman]

i almost trashed this one the other day. and then the other spare i bought broke down. when i opened it up the magnet on one side of the case was broken. so i swapped cases and now i have one good motor made from two different motors. if i would have known an hour ago. i could have just replaced the magnet in the one case as they only clip into the case. and they arent glued in like i thought they were. here are pictures of the insides of a wiper motor. the broken magnet as well as the inside where the magnets clip into the case. the park switch and the brushes too.







tags: park switch wiper motor brushes armature field magnets

[fordman]

now i have one last question on how to test the armature to see if it is any good. do i run a continuity test between each place that the copper wire hooks to the brush pad?

[Thunderfoot]

now i have one last question on how to test the armature to see if it is any good. do i run a continuity test between each place that the copper wire hooks to the brush pad?

Yes more or less... You want to test that there is no continuity between each pad next to each other, and that there if no continuity between the pad and the shaft (short to ground). If you have an ohm meter you can check the resistance of each of the fields and compare it to the others they should be close to the same.

[fordman]

ok thanks.