# Bad Albright Contactor



## jaspersk (Jun 26, 2008)

I have the reversing contactor from Cafe Electric. Albright sw202a.

It has been working fine for 2 months but today it seems to have broken. The coil picks up and the aux contact closes but there is no continuity on the main power contact. It is open regardless of whether the relay is picked up or not. I haven't tried to take it out or take it apart yet. Has anyone seen this problem before? It is strange because I can hear it pick up but there is no continuity.  For now, I have bypassed the contactor so my car is still runs but I will actually have to use the reverse in my transmission now. Not a big deal but I paid $200 for the contactor so I could flip it in reverse with a switch.


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## madderscience (Jun 28, 2008)

I use electronic reversing too, I went so far as to remove the reverse gear components from my transmission entirely.

I have the same contactor I think:

http://www.amphibike.org/images/640_reversing_contactor.jpg

If it is a reversing contactor, then there are TWO coils. Are they both opening/closing correctly? Maybe one of the two coils has quit (or whatever circuit you have that drives them is faulty)

disconnect your traction battery and control circuits and play with the contactor directly using 12V or whatever it needs to drive the coils and see if it works that way. Albright contactors are supposed to be pretty rugged so I would not immediatly assume a new one has failed. But if it has, it should be easy to diagnose. You can buy just the coils if that is what failed, you don't need to buy a whole new unit.

As an aside, The reversing circuit should be designed such that if both coils are energized (a fault condition) or both are not energized (ignition off), the circuit between the motor and the controller is open. The other alternative is shorting out one of the motor windings which would be very bad if you were to apply traction power. 

Here is my traction circuit, with reversing contactor:

http://www.amphibike.org/images/1024_HV_Circuit.gif

If you were to put the common pins of the contactor onto the battery/controller side, then the controller/motor would short out if you applied power when the reversing contactor coils were either both energized or both not energized.

Good luck.


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## jaspersk (Jun 26, 2008)

madderscience said:


> I use electronic reversing too, I went so far as to remove the reverse gear components from my transmission entirely.
> 
> I have the same contactor I think:
> 
> http://www.amphibike.org/images/640_reversing_contactor.jpg


Yep. Same one.



madderscience;124547
If it is a reversing contactor said:


> Both coils function. I can see the contact move when power is applied to the coil and of course I can hear it. The reversing contactor allows power through but the forward contactor no longer does.
> 
> I bought it from CafeElectric with my Zilla so I sent Omar a note. We'll see if he has any thoughts.


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## madderscience (Jun 28, 2008)

geez, there really isn't much else that can go wrong with a big contactor if the coil is good. 

The only other thing that could stop it from conducting electricity is if the contacts are severely burnt or damaged, or if there is something preventing the solenoid from closing completely, like some dirt or something that has gotten into the unit. Of course it would not work if the contacts had welded, but you say you can hear/see it move so this should not be the case. Was this unit switched under load?

Does the zilla/hairball employ any kind of feedback mechanism to detect when the contactor is reversed/forward, such as limit switches or something? Maybe that is what isn't working, and the zilla won't provide the go juice because it isn't getting the signals it wants to see. Is it reporting any error codes? I am out of my element with zillas so I will stop guessing there.

Good Luck.


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## jaspersk (Jun 26, 2008)

madderscience said:


> geez, there really isn't much else that can go wrong with a big contactor if the coil is good.
> 
> The only other thing that could stop it from conducting electricity is if the contacts are severely burnt or damaged, or if there is something preventing the solenoid from closing completely, like some dirt or something that has gotten into the unit. Of course it would not work if the contacts had welded, but you say you can hear/see it move so this should not be the case. Was this unit switched under load?
> 
> ...


Yeah, that is why I am scratching my head. I actually haven't gotten around to wiring up my reverse switch so it only goes to forward. The Zilla controls it and only switches it when I turn the key on or off which I haven't done under load. It is installed vertically and there is a lot of stuff in front of it so it is difficult to do an inspection. I need to disconnect all of the wiring, pull it out, and take a closer look at it. It must be something stupid like a little piece of plastic fell in there or something like that.


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## Wirecutter (Jul 26, 2007)

FWIW, I've had a section of an Allbright reversing contactor fail because I closed a contact on a bug. Yes, an insect. It cause enough resistance that, even after it was burned through, the junk on the contact caused incredible heat, pitting, and general destruction. (If you want to see the activity just prior to contact failure, see here: http://www.youtube.com/watch?v=9VLRjui3zvg)

Oh, and frying a contactor contact smells awful. Anyway, I replaced the offending section with a section from another spare contactor I had which, luckily, had the contact parts I needed.

-M


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