MEP 003a would trip dc circuit breaker when attempting to start

[dfullerpt]

Starter lock out still needs to be jumped...... But found we can get a voltage reading and rheostat works when reconnection switch on 3 phase we see voltage when selector switch on control panel set to L2 amps, L2-L3 volts.
No meter reading when on L1 amps, L1-L2 volts although terminal lugs read fine. same again no meter with L3 amps, L3-L1 volts again voltage correct at lugs.

single phase no voltage meter reading when reconnection at 1 phase 2 wire lugs test fine rheostat working, Meter shows voltage when on 120/240

 

[Speddmon]

From the sound of it, the meter is working properly if you are getting an adjustable reading when you have the selector set for L2 amps and L2-L3 volts. So that tells me that your ct/cvt assemble is possibly kaput. It is a royal pain in the butt to get to, first you need to make sure all of the control wire connections on it are clean and tight. Then if it still doesn't work you can do a check of the resistance of the ct/cvt assembly to see if it is within spec. To do both of those checks you need to pull the front cover from the output box. This is the box where your big connection lugs are at. You have to carefully remove and tag all of the control wires on the large CT/CVT assembly at the bottom of the box right up front. It's a large plastic piece with 3 holes in it that your generator wires wrap through several times. It is imperative that you tag the control wires because they have to go back on in the correct places or it won't work at all. Once you have the control wires off of it (there is no need to unwrap the large wires from it) Then you use the procedure in the TM to check the different pairs of the coils of the CT/CVT. The proper readings should be on page 6-15 of the -34 TM, sections 7 and 8. If it is not within spec, I have some complete output boxes I could be talked into parting with (Of course I would test them to make sure they worked first).

 

[dfullerpt]

Thanks another hurdle to go over. Worst part is I should have my brother in laws here so they can at least learn as we go trouble shooting. I can hear it now when this unit goes to the lake and something happens they will have no clue (like me)on how it works
Oh but I am learning thanks to everyone on the site

 

[dirtyfingernails]

Speddmon et al.,
Don't want to hijack the thread, but I was unaware not to idle the unit. I've been starting mine with the throttle all the way in (idle), then bringing it up to 60 Hz. Then I drop it back to idle and shut it down. Please school me here, what is correct? Also, on my test run yesterday (every 3 months) I had to start the unit 3 times to get it to produce electricity. Why would I have to repeatedly flash the field to generate? Thanks.
DFN

 

[doghead]

In the -12 Operators manual, it says this.

2-4. STARTING GENERATOR SET (SEE FIGURE 2-3).
CAUTION
Do not idle engine.
Operate generator set only at rated RPM.
Do not use either to aid starting generator set.​

Consider you have a generator that originally cost thousands of dollars. The least you should do is, Download and read the TM's for it.

btw, does anyone know the original acquisition cost of these gen sets?

 

[dfullerpt]

My wife gave her brothers and I "T" shirts that said real men don't need instructions
I had bought the manuals from Military info prior to getting the Gen set home however the print is real small still no excuse for not reading. Got so used to starting up construction site Gen sets that just go right to speed never gave it a thought. Fortunately I am hoping we have not caused any damage to this set which is said to have cost $8832.00 when new. I am now thankful for this site as I have found the manuals in the resources area and some very help full individuals. And I am reading trying to learn about some of the trouble shooting areas still helps that if I am not sure I can ask for HELP Thanks again to all for the help and yes I still Hate Electricity

 

[dirtyfingernails]

Doghead, You're absolutely right. I have the TMs, just never remember seeing that. I'm not the smartest tack in the box--as they say. I will look again. You learn every day!

 

[dirtyfingernails]

That is...sharpest tack in the box...told ya!

 

[Speddmon]

DFN,

When you run the set at much lower than rated speed, the electronic parts inside are working overtime to produce the proper voltages. Overtaxing the VR and Bridge board will lead to premature failure of the components.

I would check to see if the flashing is necessary each and every time you start it up...it may have just been a freak thing for this on time. Also, when you said you had to start it 3 times to get it to produce power...did you shut if down or just move the selector switch back to the start position for a few seconds? You do not need to shut the set down to flash the field. That's the purpose of the start lock-out switch that dfullerpt is having troubles with. It enables you to move the selector switch back to the start position without engaging the starter once the set is running.

 

[dirtyfingernails]

Speddmon,
Thanks. I looked my paper copy of the manual (-12) and read it again thoroughly. I still couldn't find where it says not to idle it. My version is dated 1977. I won't do that anymore! As far as moving the selector back to start while running, I tried that the first time and it sounded like the starter was clashing with ring gear. So, I shut it down and restarted --yes 3 times. It produced electricity on the third try. BTW, when I moved it to start on the first attempt, it didn't result in any change. In other words, it still wouldn't produce power. What should it sound like when I move to start position while it's running? Thank you!

 

[Speddmon]

DFN,

Don't get too worked up about missing the excerpt from the TM that DH posted. That line is only in the TM for the 002a for some reason. The TM for the 003a doesn't have it in there, but they are essentially the same electronics, so the same rules apply.

As to the start switch and what it should sound like...you shouldn't hear anything. The starter lock-out switch should have opened up when the engine came up to speed, and not allowed the starter to "clash" with the ring gear. There are two possible explainations for why your started tried to engage.

1, You tried to flash the field while the engine was idling? I don't know if this is true or not, and I don't even know if it would have made a difference. The starter lock-out switch opens using centrifugal force of the rotating engine to open the switch. However, I can't find in the TM a specific number of RPM's as to when it is supposed to open. It is possible that the engine just wasn't going fast enough to open the switch.

2, Your starter lock-out switch is out of adjustment...a very common thing. The adjustment procedure is in the -12 TM on page 4-31. While it's not a complicated adjustment, the "arms" of the switch are very thin and easily bent out of whack.

 

[dirtyfingernails]

Speddmon,
Thank you sir. I probably was at or near idle when I attempted to flash...remember that was my SOP for starting the unit. I will see what happens on the next test run in 3 months and then adjust the lock-out switch as suggested. By the way, oil pressure built within seconds with your spin on filter kit! Previously, I would have to hold the start position for a pretty long time to build enough pressure. A very good investment!
DFN

 

[Speddmon]

No need to wait 3 more months, unless you just don't want to burn any more fuel. I'm curious to see if starting it at rated speed helps with your generation problem as well as the starter lock-out switch.

If you didn't leave it set for 60 Hz when you shut if down last, pull the throttle control out about 3/4" or so and start it up. At the very least that will be closer to a 60 Hz start-up. It may start generating right away. Even if it does, set it for 60 Hz and then try the manual flash again for just a second. It won't hurt anything and it will allow you to see if your starter lock-out if set right or not.

And when you shut it down, have it set for 60 Hz and don't touch the throttle knob, just shut it off. Then the next time you start it up, it will go right to operating speed and be set at 60 Hz for you.

 

[dirtyfingernails]

Got it. I will try to give her a test run tomorrow afternoon and follow your instructions. I've had the unit for a couple years now and it never did this before. I only test run it once every 3 months for about 30 minutes. Thanks again!

 

[DieselBob]

DFN,

Don't get too worked up about missing the excerpt from the TM that DH posted. That line is only in the TM for the 002a for some reason.

That explains why I couldn't find it. They also have that in the TM for the 018a.

 

[dfullerpt]

Just wanted to Thank everyone who helped out with tips and advise in getting this generator running. Special Thanks to Tom (Speddmon) for all his help and great adapter.
We took it to the lake and with some rigging got it into the room we built for it.
Fired it up and put a 20 am load on it. We had a slight problem we lost the oil pressure switch but after jumping it out ran it for 12 straight hours with ZERO issues. Unit just purrs burned 6.5 gallons oil pressure stays at 35 lbs. My brother in laws were skeptical until we loaded it with every light, microwave, ice machine, ceiling fan, etc. They never saw the lights even flicker....

Need to run exhaust out to keep temp in room down we have a couple of attic fans mounted in the wall they don't move enough air so we ran with the door open.

THANKS AGAIN
Dennis