What component is this ?

[Widget]

Hi all,

I'm trying to repair a window wiper motor which seemed to have water damage. I've cleaned it up but one of the three brushes was badly damaged. Looking at it, it seems to be some sort of electrical component, perhaps a resistor?

Is anyone able to identify it? I had a Google but no matches.

Thanks

[redwire]

Re: What component is this ?

It's a PTC fuse, to prevent the motor from burning up if the wipers are jammed due to snow and ice. Here, the wiper fuse usually blows if they are jammed but the fuse can be huge like 20A.
Australia, not sure what would jam wipers down there. Maybe a roo on the hood lol.

cross-post: https://www.eevblog.com/forum/chat/w...s-this-381077/

[redwire]

Re: What component is this ?

The chip-style PTC you have is custom for car makers.
For a replacement, measure its area which is in proportion to it's current rating. The thickness proportional to the voltage rating.
Roughly 16*12mm is 8A, 20*16mm is 10A hold. They come epoxy dipped with leads, for automotive it's a 16V or 30V rated.
Example:
RGEF1200 12A hold, 20.4A trip
RGEF1000 10A hold, 17.0A trip
RGEF800 8A hold, 13.6A trip
RGEF700 7A hold, 11.9A trip

I would also gauge by the branch circuit fuse size in the vehicle.
Lower voltage rated perform better I thought. Keep in mind it's hot under the hood.

[Widget]

Re: What component is this ?

Sorry for not getting back to you sooner, Redwire. Thanks for the information, much appreciated .

So if that fuse is dead (as pictured), would the whole motor not work?

I ended up replacing the motor with a new (used) one, which worked straight away. , but I'll keep this info in mind for the future.

[redwire]

Re: What component is this ?

Your new motor looks way cheap compare to the old one? The brushes and commutator seem much smaller and the construction cheap with metal shavings everywhere.
I would've swapped the PTC fuse over. If you short it out/bypass it on the old motor it should work assuming the motor is good.