MEP-002 – high voltage output – T2 transformer and R1 questions…

[445gsdss]

I purchased a MEP-002 a few months ago and the seller did not disclose the it had a voltage output issue. (In all fairness they might not have known…) Anyhow, when the genset is setup for 120v/1phase it is outputting 140 volts. I opened a thread on this a few months ago and was advised to first rule out the regulator by disconnecting lead #17 and observing if the voltage went any higher or not. (link to thread below)

I was finally able to get around to doing this over the weekend and, sure enough, the voltage jumped to 160v with lead #17 disconnected. I believe this points to either the T2 transformer or the R1 voltage output adjustment dial.

I have a couple of questions…

Any guess on which is more likely the component that failed? I can say that turning R1 provides NO change in the output frequency with either lead #17 connected or not…

Does anyone know where I might find a T2 transformer or the R1 dial? Any guess on how much they might run?

If I can locate them, how frequently do they fail – should I buy a couple to save on shipping and have a spares? (or is this more of anomaly?)

Along this line, should I just buy both assuming that I’ll need the other spare as a future replacement for the present good component eventually? (I don’t want to drop money on say a T2 transformer to find out that it is isn’t the component that failed, and then have a spare I’ll likely never use – but on the other hand is they do fair somewhat regularly, I’ll buy at least one of each and not worry about it…)

http://www.steelsoldiers.com/showthread.php?116155-MEP002A-holding-at-140-volts

Thanks!

445GSD

 

[cuad4u]

I assume you did your voltage measurements with a good accurate external VOM and did not rely on the panel mounted volt meter in the MEP. If so the first thing I would do is see if the voltage adjust pot on the MEP panel will vary the output voltage at all before you go any further.

I just helped a friend with a similar problem. A couple of squirts of DeOxit on the voltage adjust pot on the panel and a few turns to exercise the pot did the trick. I know his gen sat outside in a yard uncovered for at least 3 years. Apparently there was some crud or corrosion on the pot.

I am brand new on this site, so take my advice with a grain of salt. I always try to look for a simple fix before digging into the innards.

 

[Jimc]

pull the wires off the voltage adjustment pot. take a voltmeter and set it to ohms. off the top of my head i believe its a 1k ohm pot. check the pot to see what the resistance is between the 2 contacts then turn the dial up and down to see if the resistance changes. no change then you can try a little deoxit like cuad said. that stuff works well. if not then you will prob need a new one. its a 2 min test so i would do that before i looked at anything else.

 

[445gsdss]

I pulled the T2 transformer before the replies to this thread - not a big deal since it was straight forward. It tested out with an VOM (set to ohms) per the TM. H side is 148 (serviceable range 155 +/- 15) and X side is 18. (Serviceable range 18.8 +/- 1.8


I'll check out the pot as recommended next. I *think* someone had stated previously (when I'd posted my first thread) that the pot was only for small adjustments, but it sounds easy enough to check and possibly to try adjusting. It just seems that, even if it were off, I'd see some sort change when adjusting the R1 rheostat, but there is nothing. I use the onboard (analog) gauge for looking for any change when adjusting R1, but at same time have a digital volt meter plugged into the aux outlet. I also use my VOM to verify voltage on the output lugs as well. all 3 always match. With jumper #17 attached to regulator I get 140 volts at all 3, and with it disconnected I get 160.

 

[Jimc]

for my test above that was for the voltage adjustment right on the front control panel

 

[Speddmon]

Make sure the voltage adjustment rheostat is wired properly also. I bought some spare control panels one time and the rheostat in one of them was wired in such a was as to never be able to adjust it.