Master contactor question

Sid Lambert · #1 11-14-2008, 04:56 PM

Ok guys, I'm still trying to run down some electrical issues.

I found something today that is unrelated but I would still like to remedy.

The master contactor is wired from the battery positive to the switch on the panel then to the 3rd post on the contactor. It does not connect to ground like I am used to. The contactor is all metal but I'm not sure if it is a continous use contactor or a starter relay.

With it disconnected from everthing, the input side has no continuity to ground but the output side and the 3rd pole do. Can someone verify this is correct?

SteinAir · #2 11-14-2008, 10:28 PM

Not what I'd call a "standard" continuous duty relay that we normally see on aircraft for master relays. You are correct in the fact that "most" of them use ground to trip the relay. If it were me, I'd probably get rid of it and install a normal one like 99.9% of airplanes have on them.

Cheers,
Stein

MCA · #3 11-16-2008, 05:17 PM

Sid, Take a look at our Contactor Wiring document located here: http://www.verticalpower.com/documents.html towards the top of the page. It is an overview of the different types of contactors used in experimental aircraft, and step by step instructions how to wire them properly.

Sid Lambert · #4 11-17-2008, 05:44 AM

I think it was a starter relay. $20 later and it has a new master contactor from ACS installed in it. This time it works from a ground like I'm used to.