mep804a has no output

[Jsampo85]

Ohhhh ok i gotcha, i had read somewhere that you were supposed to read voltage across those 2 pins. Safe travels while you are on the road!

 

[TacMac2012]

Sorry for the hijack but I am having a similar issue. When I start the generator I am only getting 6v from each leg, and 12v across two lugs. The voltage gauge on the panel reads the same low voltage. Turning the voltage adjust knob doesn't make a difference. This is with the ac connector open or closed. Also the hz is very low. The freq gauge hovers around the lowest reading. The engine rpm does change slightly when the hz knob is adjusted.

Did you ever figure out your issue?

 

[Guyfang]

Thats a good question.

 

[TacMac2012]

I am having the same issue! It worked and ran my house yesterday, today no such luck... No voltage or hz

 

[MAdams]

Unfortunately I never found out what was wrong. Guyfang was a huge help but in the end I didn't have the time to dig deeper and I sold the unit. The guy who bought it reworks them for the concrete cutting industry and his diagnosis was the gen head was bad.

 

[Guyfang]

Sorry to hear that.

 

[155mm]

Unfortunately I never found out what was wrong. Guyfang was a huge help but in the end I didn't have the time to dig deeper and I sold the unit. The guy who bought it reworks them for the concrete cutting industry and his diagnosis was the gen head was bad.

unlike button

 

[Texasbosshawg]

i got power to one side of the AC contactor but not the back side. I got about 210 volts Ac on the front side and not much of anything on the back side.. Ive been having **** finding the correct trouble shoot in the manual..

My gen starts but voltage and hertz ONLY go up when holding the switch to start for 6 sec. One i release they go to nothing.. I checked the fuse on the voltage regulator, its good. I checked for 11 volts on pin 7 on my s1 switch and its present. I disconnected terminal 1 wire 141 A on the voltage regulator and started it and.. my under voltage light is still on.. My interrupter wont stay closed. whats next if my AC Contactor is getting roughly 19-24v AC on both sides?

 

[Texasbosshawg]

i been trying to reach you on another thread same issue. I was doing the AC contactor troubleshoot you had suggested.. i got 19-24volts AC on both sides, now trying to test the magnetic pickup but cant find what it looks like and your manual must be different because when i got to figure 18 item 19 its something else.. do you have a pic. or can you give me the troubleshoot. These manuals have been the worst to find stuff in?

Original issue is the same. I let off my s1 switch after 6 seconds and my voktage and hertz drop to nothing. Fuse for the voltage regulator is good, tested pin 7 on S1 switch it was 11volts when turned to the start position. so here i am trying to figure out where this magnetic pick up is?

 

[Texasbosshawg]

What "Breaker" are you talking about? Do you mean the Ground fault interrupter, (GFI). TM 9-61115-643-24P, Figure 7, item 22. Is that what you are talking about?. On the side of the GFI, there is a small switch or reset when the GFI gets tripped. The GFI only trips when you have a ground fault problem. Or do you mean CB-1 breaker? Behind the control panel door.

To find the A.C. contactor,take a look at Figure 16, (output box assembly, in the TM. It shows you the contactor as item 36. There is a cover on both sides of the contactor, to prevent anything from making contact between the AC output cables. Like your hand, or a wrench. Two screws hold the cover on. Remove both covers. Start the set. Measure between all three cables on one side. Between any two cables you should get about 220 volts, as you are measuring between two phases. Any voltage? If not, Measure between the cables on the other side. Any voltage? If not, perform the same test while someone like your best friend, holds the start switch up while you do the test. Remember, this thing produces electricity! So be careful. Do not drop anything metal into the works. Might light up your life!! If you have voltage on one side and not the other, the contactor is not working. May not be bad, something maybe not letting it close. Like a relay. If you have no voltage on both sides, then the Main Generator is not being excited, or not "lighting off" when it gets excition. But lets first start by testing the main AC contactor. AND FIRST, like MtnSnow wrote above, GET THE TM's!!!!!!!!!!!!!! The troubleshooting diagram in the back of the book is not bad. Are you getting any idiot lights, (Fault indicator lights) coming on at any time? We need more info.

i got power to one side of the AC contactor but not the back side. I got about 210 volts Ac on the front side and not much of anything on the back side.. Ive been having **** finding the correct trouble shoot in the manual..

My gen starts but voltage and hertz ONLY go up when holding the switch to start for 6 sec. One i release they go to nothing.. I checked the fuse on the voltage regulator, its good. I checked for 11 volts on pin 7 on my s1 switch and its present. I disconnected terminal 1 wire 141 A on the voltage regulator and started it and.. my under voltage light is still on.. My interrupter wont stay closed. whats next if my AC Contactor is getting roughly 19-24v AC on both sides?

 

[Texasbosshawg]

The voltage produced and measured from the Mag Pickup should NOT exced 3 volts. Adjust the mag pick up as described above. If for some reason you can not adjust it down to 2.5-3.0 volts, the pickup is bad.

I assume by 3A limitron fast acting KTK-3 bus fuse, you mean the Quad circuit fuse, to protect the excitor windings. If your Volt regulator is defective, and sends to much voltage to the exciter windings, they burn up. Hence the fuse. You can measure how much voltage is going to the windings, by removing the fuse and measure from ground to the input side of the fuse holder.

I disconnected 16 and 17 got 3.8. Now i need to know what that magnetic pick up looks like so i can adjust it.. do you have a pic? when i google it tons of stuff comes up but nothing that looks like what youre describing and when i search it in the manual i turn up nothing?

 

[bgoebel]

I may be having similar issue with MEP 804a
Mine produces power sometimes while testing but now ready to hook to load and its not. Sometimes getting power at start up sometimes not so thought maybe it was the circuit interrupter/contactor. Checked the magnetic pickup and put it back in but haven't done voltage testing. I didn't see the previous post with the detailed instructions til now. Engine will not start now. Help? Guyfang?

 

[Guyfang]

I may be having similar issue with MEP 804a
Mine produces power sometimes while testing but now ready to hook to load and its not. Sometimes getting power at start up sometimes not so thought maybe it was the circuit interrupter/contactor. Checked the magnetic pickup and put it back in but haven't done voltage testing. I didn't see the previous post with the detailed instructions til now. Engine will not start now. Help? Guyfang?

Back up. One problem at a time.

Have you downloaded the TM's? Have you looked at them.

Is this set new to you?
Has it ever worked right?

The "sometimes" making power could be because you do not hold S1 in the start position long enough.

You need to measure how many VAC you have out of the Magpick up. 3 VAC will do it. Then it might start. FIRST test the Mag pickup. Then we can go another step.

 

[bgoebel]

ok guyfang
appreciate your help
I have looked thru some of the TMs on green mountain generators.com. Did not find your reference for the mag pickup, so maybe there are older and newer versions of the manuals.

This is new set to me. Bought two months ago thru govplanet auction, out of las cruces NM

I got good voltage out of it first time i tried it, just using a drill on 110 outlet, and on all 3 legs of 3 phase 208 volts using the meters on panel. I dont' remember if i used my tester on output lugs.

Last week had another guy hookup a panel to wire to a 10 hp irrigation pump, which i tried to get going yesterday. When he was working on it he had no power until he used the "battle short" switch. He didn't know what that switch was for, maybe i will regret that he used it. After restarting the generator at one point he got power. That made me latch onto the magpickup test that you had recommended on this group earlier.

This morning I checked and reset the mag pickup, got it as close to 3 volts as i could. I had it out too far yesterday. it is clean, but appears short. There is very little plastic protruding past the threaded housing. I have a good fluke tester, the voltage varies from 2.9 to a little over 3.

Started right up then, but just low voltage output, circuit interrupter not closing, Undervoltage light on.

 

[bgoebel]

Guyfang, if you are in germany, time difference may be an obstacle. When do you look at this stuff? Could we communicate by phone text message?

 

[Guyfang]

I look often during the day and at night. I hate phone text, as my sausage fingers and the tiny keys are a problem. And I am famous for leaving my phone on my desk all day.

OK, so the adjustment fixed the starting problem.

Next, are you holding the S1 in the start position long enough? If not, the S1 can not give the main gen its initial excitation. So, hold it in the start position 5-6 seconds longer. You can not grind the starter. The mag pickup cuts out the starter before that can happen. 95% of the no AC output problems are caused by not holding the S1 long enough. And since you sometime have power, and sometimes not, this sounds like the problem.

If the S7 battle short switch got you power, then was there a fault light on the A2 malfunction indicator? Did you reset the A2, if there was a fault light?

What is low voltage output to you?
Did you reset the A2 fault Under Voltage, and the light go out? and stay out?

Has the Quad circuit upgrade been done on your set? If so, is the fuse good?

 

[bgoebel]

Yes I am holding in the start position up to 15 seconds

i was not present when my helper (who is better at this than I am) got power. The battle short switch may have been coincidental to getting power. He says the low voltage light was lit all the time, but that doesn't make sense when he did have power, meaning 208 volts at the meter on the machine and at the lugs

A2 malfunction indicator is the same as the "fault indicator" on left side of control panel? I have pushed the reset/test button often. it has not made fault light go out.

Low voltage is 14 VAC

I don't know about the quad circuit upgrade. Where is the fuse?

 

[Guyfang]

The Quad circuit fuse is normally located next to the A1 volt regulator. Its a big fat fuse. Pop it out and test it. If its good, pop it back in. If you are still not sure what I mean, take a picture of the inside of the control cube, (cabinet) and post it.

A2 is the fault indicator. If you look at the doors of the set, you will find schematics for the set. If I call out a part, and you don't know it, try looking at the schematics.

The S7, (battle short) switch is made to override some of the generator safety features. So its possible that he could have had it on and bypassed the relay. Then you could have 208 VAC on the meter and lugs.

If the quad fuse is good, pop it back in.
Turn S1 to the start position. AND HOLD IT THERE! Do you have normal Volts on the AC meter?
Flip on the S7.
Release S1.
Do you get a under volt light on the A2? Do you have normal volts on the AC volt meter?

 

[bgoebel]

Quad fuse is good

Started, held in start position, low volts on AC meter (25 or less)

Flip on S7, no difference, release S1 no difference

Under volt light on A2 is lit.

 

[Guyfang]

OK.

Start the set up, and while doing that, measure to see if you have 24 VDC on S1, pin seven, AS LONG AS YOU HOLD UP S1 in the start position. This is the excitation voltage, to the main gen. It comes from S1-7.