Ammeter

[rubixcube2k3]

In flight my Ammeter (when I had an analog gauge) reflected a negative value. On the ground with the engine off, but electronics on, it would reflect a positive value. I chalked it up to being something flaky with the gauge. Now with my MVP-50, it still does the same thing. 

Is that normal? In my mind, it should read positive when charging and negative when discharging. By that logic, it would stand to reason that it is discharging when the engine is running and charging while it is not?

 

Advice or opinions?

 

Thanks, 

Abe

[Mooneymite]

Everything I know about electricity I learned years ago when I stuck a key into a 110 outlet,   but everytime I've had an issue with the ammeter in my 'C', I've fixed it by cleaning the ammeter connections on the shunt mounted on the interior firewall co-pilots side.

Perhaps not elegant, but cheap and simple.

 

[DXB]

As simple as reversing the ammeter lead connection somewhere?  Alternately, you may live in an antimatter universe 

[1964-M20E]

you could try swapping the wires on the shunt that should take care of the problem.

 

 

[Guitarmaster]

Definitely sounds like reverse polarity.  In that case, what he said.  ^^^

 

 

[rubixcube2k3]

Thanks everyone! I'll put a volt-meter on the shunt when I get back home Tuesday and see if It is reversed polarity. If so I'll get with my A&P to reverse and of course log it :-).

 

Thanks! 

Abe

[Yetti]

Turn on the landing light without the engine running and you should see discharge.  If it was not logged as being reversed, not sure you log un reversing it....   Still have not figured that one out.   If you remove the wheel to replace the brake line... on the brake replacement is logged.  Maybe I am confused.  

[rubixcube2k3]

On 12/18/2015 at 4:36 PM, Yetti said:

Turn on the landing light without the engine running and you should see discharge.  If it was not logged as being reversed, not sure you log un reversing it....   Still have not figured that one out.   If you remove the wheel to replace the brake line... on the brake replacement is logged.  Maybe I am confused.  

I'm not sure, but I know certain things are owner approved maintenance, and others require a A&P Signoff. So my reasoning for logging is simple. 1.) I'm a stickler for the rules. After having problems with a poorly documented aircraft in the beginning, I've spent too much money and time redoing things that may have been done before but weren't documented. That being said, IF I ever sell this plane, I want there to be nothing missing from the logs. And #2 I have a wonderful relationship with my local A&P/ IA, I don't want to jeopardize his trust in me to do owner assist maintenance either.

[jetdriven]

You aren't jeapordizing his trust if you have him supervise you doing the work.  

[rubixcube2k3]

4 hours ago, jetdriven said:

You aren't jeapordizing his trust if you have him supervise you doing the work.  

Agreed. I only meant that I didn't want to go inspect it, reverse the wires, and not document it nor have him supervise. Should have clarified that initially.