oops, fried regulator?

[Wheels]

Ok, here it is on the forum for all the world to see. I bought a battery to start my kit fox 1200 with a rotax 912. The terminals were backward to the one I pulled out and I didn't notice the orientation difference. At first start the starter ran backwards! Just the starter, not the prop. I didn't make a second attempt. I was in shock. I investigated, corrected it, started the engine and the VOLTMETER reads zero. the fuses to the voltmeter and the voltage regulator are visually fine. But I suspect I fried the voltage regulator. Can I test it? How? I have a fluke meter but never have learned the finer points of electrical troubleshooting. the learning curve is high today.

[HighWing]

I am definitely not the expert you are looking for, but it would seem to me, that even if the regulator is fried, your panel volt meter should read the voltage it is connected to - the voltage output of your battery. What does it show with the master switch on and the engine not running. That is the first thing I would check with the Fluke to see if it and the panel meter are reading the same. If it shows a voltage, I would leave the clips on the battery and start the engine and then see what it reads. If it is the same, the regulator could be gone. If it reads a higher voltage, it would suggest the regulator is charging the battery. How to check the regulator with the Fluke? I have no idea.

[Wheels]

I was flying one time when I lost the voltage regulator. the volt meter just went to zero and stopped charging the battery, so when I replaced the regulator, the voltmeter showed the charging system at 12+ volts again. So, that being said, I think its possible to lose one and not the other, but I am going out to start the plane and see if I can read voltage with the fluke.

I'll keep you posted.

[Av8r_Sed]

If you've got a protection diode on the starter relay (most likely), it may have fried with the reversed polarity. It may be now acting as a short circuit and your regulator output protection could be triggered.

Many multimeters have a function to check diodes. See if you can isolate the diode from the coil and test it. Also check any other protection diodes on relays in your system. Hopefully you haven't toasted anything too expensive. Fuses only protect against overcurrent. They may not help you for reversed polarity.

[Wheels]

Thanks for the tip on the possible diode problem. I'll search the threads here and rotax owner. com and see if there are any "short schools" on troubleshooting. I went to get the fluke meter and didn't find it but do have a multimeter, (im reading the manual.)

[n85ae]

Don't get led astray with "Fluke" meter, etc. This is not the issue. This could
could be troubleshot with the cheapest meter you can find. Or even in a
pinch with a flashlight bulb, a battery and a couple wires ... Seriously
this is not the issue.

These light aircraft electrical systems are super super simple, however
that is because I have an electronics background. The questions you are
posting suggest that your background is probably something else.

Really the best advice I can think of - Is that you should seek somebody
who has an electrical/electronics background to help troubleshoot your
problem in person.

This is not meant to be insulting, but troubleshooting like this is very simple
and making a really minor mistake can end up doing a lot more damage (i.e.
smoke, etc).

Get somebody with experience to help you in person, NOT a forum. Contact
your local EAA chapter, I'm sure they have somebody who would run over
and help out for free.

Regards,
Jeff Hays

Thanks for the tip on the possible diode problem. I'll search the threads here and rotax owner. com and see if there are any "short schools" on troubleshooting. I went to get the fluke meter and didn't find it but do have a multimeter, (im reading the manual.)