⁸What causes under voltage error in MEP-805B? Sometimes it runs fine, but ultimately will show this errer and stop generating. Seems to heal itsel

[SteveTheGreen]

MEP-805B ?

 

[robertsears1]

Are you making sure to hold the switch in start several seconds (>10) after it is running? There are several interlocks that need to be satisfied just after start to operate correctly. Read the starting instructions probably on the inside of the lid that covers the control panel and follow them exactly.

 

[NDT]

The B phase is 16 volts under the A phase. And down to 201 volts which is too low for a 208 circuit. Is your entire 20 kW load hanging on the B phase?

 

[Guyfang]

Before you start load testing, you need to fix whats wrong with the set.

 

[Chainbreaker]

No experience with your Model Genset, however...when people describe faults that intermittently "heal themselves" the first thing I would do is check all wiring and connector contacts. I typically pull all connectors apart and spray with contact cleaner (Deoxit) while looking for anything out of the ordinary...burnt or loose contacts, loose/broken wires etc. If that does not reveal any problems I usually grab a schematic and look for components in the circuit that is presenting the problem.

Of course, if there were "diagnostic tests" that could be run that may reveal the issue quicker.

 

[DieselAddict]

+1 on spending some time on the wiring. Go wiggle every connection and make sure everything is tight. I've found SOOO many loose connections in sets. That is the kind of stuff that will drive you to drinking if you are chasing symptoms instead of going back to basics and looking for bad connections.

 

[SteveTheGreen]

Only one leg is registering now.

 

[SteveTheGreen]

Started using exact procedure on display cover. Held to start for 5 seconds. All legs registered, but two legs were at 200 and the one was 215. Held down start and reset switches, but no changed. Closed the circuit in parallel with another working generator. It shared the load, but didn't sound right. Opened the circuit on the working generator to make it take the entire load and it got the undervoltage error and quit generating.

 

[SteveTheGreen]

The B phase is 16 volts under the A phase. And down to 201 volts which is too low for a 208 circuit. Is your entire 20 kW load hanging on the B phase?

B & C are both well below A. We need all three phases operational if that's what you are asking. It shuts itself down if phases B&C are too low, like below 200.

 

[SteveTheGreen]

My other generators register 216 on all three legs.

 

[DieselAddict]

Have you verified the voltages using a voltmeter?

 

[NDT]

I would refrain from paralleling until you get this fixed. Can you describe what your 3 phase load is? Load shouldn’t be all between one phase and neutral.

 

[SteveTheGreen]

Have you verified the voltages using a voltmeter?

No. Where/how do I do that?

 

[SteveTheGreen]

On a whim, I fired it up. Now it healed itself. It must be a short in something. Suns out and warmed it up. Any ideas?

 

[Guyfang]

No problem "goes away". You need to read the TM if you do not know where and how to check voltage on the three phases. Go back to post #5 and start there.

 

[SteveTheGreen]

I would refrain from paralleling until you get this fixed. Can you describe what your 3 phase load is? Load shouldn’t be all between one phase and neutral.

Load on each phase varies. This morning phase 1 was 216, 2 = 110, 3 = 108.
Typically, phase 1 is 216, 2&3 are 195. I get a low voltage error and it runs but produces no electricity.
It's 4pm now. I fired it up and all three phases are 208.

 

[Guyfang]

Load on each phase varies. This morning phase 1 was 216, 2 = 110, 3 = 108.
Typically, phase 1 is 216, 2&3 are 195. I get a low voltage error and it runs but produces no electricity.
It's 4pm now. I fired it up and all three phases are 208.

I would refrain from paralleling until you get this fixed. Can you describe what your 3 phase load is? Load shouldn’t be all between one phase and neutral.

NDT is asking you what your load is, and not what the voltage is. What are you using for a load? Is it a three phase load? what have you hooked up, and HOW is it hooked up?

 

[DieselAddict]

No. Where/how do I do that?

What experience do you have with power systems? I'm concerned that your response to my question suggests you are just getting started. Poking around in live circuits is certainly hazardous. You may want to reach out to someone experienced in the hands on stuff that can help you get started in the troubleshooting.

One thing to remember when doing troubleshooting is to not assume the gauges on the machine are reading correctly. Everything needs to be verified with known good measurement tools.

 

[SCSG-G4]

And remember that old advertising slogan, "If that reading is correct, it must be a Fluke!"

 

[Guyfang]

And remember that old advertising slogan, "If that reading is correct, it must be a Fluke!"

Simply the best. Even a cheap Fluke is better then most of the rest. Durring the ramp up for the first Sand Box War, the ADA (Air Defense Artillery) world needed a hand held digital multimeter that read hertz, for the Patriot system. My boss asked me for the name of a very good meter, and I of course said, "Fluke". Our major command called the Fluke company, and spoke with John Fluke Sr. who was founder of the firm, and was still in charge. He sent his Son, John Fluke, Jr. over to Germany, with 15 hand held meters. The 8060 model. Cost at the time was over a grand, each. He gave 14 meters to the 32nd AADCOM Chief of Staff, and the last one to me, as a gift. It was the best meter I ever held in my hands, bar none. I used it until just a few years ago, when I stupidly loaned it to someone. Somehow he managed to break it.