Mep003 voltage drop after 7500w

[Dog Breath]

This unit will run my 7500w heater for hours. If I add 1300 more watts my hertz goes from 60 to 63, volt drop from 240 to 140 then up to 180, load% from 55% to 30%.
When adding the extra load it seems to electrically drop then pick up drop pick up.
The engine runs strong and does not bog down.
Breakers do not trip
When I go back to 7500w/55% load everything goes back to normal and runs great.
I’m not sure where to go from here

 

[Scoobyshep]

The voltage crashing leads me to believe there is a failure in the AVR.

Basically the higher load requires a stronger field and the avr is not keeping up causing the voltage to crash. This in turn causes less magnetic field and makes the rotor spin easier causing the spike in frequency.

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[Dog Breath]

@Scoobyshep are you talking the voltage regulator? I have a new ac vr installed in the control box.

 

[Scoobyshep]

@Scoobyshep are you talking the voltage regulator?

Yes.

Avr= automatic voltage regulator

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[Dog Breath]

This control box has a new avr from kloppk. I could switch avr’s from another unit to check

 

[Scoobyshep]

Hey would be the better resource here. If it were me and I were troubleshooting I would measure the field voltage and observe it as the load is increased

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[Dog Breath]

Ok I will figure out how to measure the field voltage. My electrical knowledge is limited

 

[2Pbfeet]

@kloppk is the expert.

If it were me, I would double check the wires and the wire terminals to wire connections to be sure that there isn't some loose wire(s) or internal corrosion that is causing extra resistance, and overloading the AVR. I would also give the entire field wiring circuit from the AVR to the gen head a close look for any suspicious looking portions. (Fraying, burned spots, etc.)

All the best,

2Pbfeet

 

[rickf]

I was just going to say the same thing, Check for loose wires and contact Kloppk. Too me it sounds like a loose wire that just can't carry the field load after a certain point.

 

[Dog Breath]

I checked all wires in the cubicle. Nothing loose. I exchanged cubicle with another working 003 and it works as it should 70% load 8800w with no issues. So I will have to dig into the bad cubicle

 

[Dog Breath]

Well I hooked up the bad cubicle to the other 003 and I’m getting 53 volts at the convenience receptacle and L0/L1 and L0/L3 both 53 volts I will clean connections tomorrow and do some testing.

 

[kloppk]

Unlike other generators the AC Voltage Regulator in the 002, 003 does not directly drive the exciter. It does it indirectly via the CVT and other components.
Here is an excellent video on how the voltage regulation system works.
YouTube Video

You may want to swap the AC VRs between the two boxes and see if the issue is the VR itself.

 

[Dog Breath]

I will switch vr’s later this afternoon and make sure all contacts are clean and report back. Thankyou

 

[2Pbfeet]

Unlike other generators the AC Voltage Regulator in the 002, 003 does not directly drive the exciter. It does it indirectly via the CVT and other components.
Here is an excellent video on how the voltage regulation system works.
YouTube Video

You may want to swap the AC VRs between the two boxes and see if the issue is the VR itself.

Thanks for sharing the video link! That video is a fascinating and very informative look at the rather sophisticated (I think) control system. It seems quite clever, and definitely an unusual solution in my experience. Do you have any insights about why a magnetic control system was used? Reliability?

All the best,

2Pbfeet

 

[Triple Jim]

Here is an excellent video on how the voltage regulation system works.
YouTube Video

Also note that this debunks the idea that running the engine at a speed below 1800 RPM can damage the regulator. Doing that makes the regulator put out less current to CVT1, which reduces its load.

 

[Triple Jim]

Do you have any insights about why a magnetic control system was used? Reliability?

If the regulator fails, the generator can still have output, although it's likely to be at a higher voltage than normal. But at least it doesn't cause an immediate power failure.

 

[Scoobyshep]

Also note that this debunks the idea that running the engine at a speed below 1800 RPM can damage the regulator. Doing that makes the regulator put out less current to CVT1, which reduces its load.

On this set. The bigger brothers work differently

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[Triple Jim]

On this set. The bigger brothers work differently

Most other generators in the world work differently. It's our 002A and 003A generators that use the mag-amp system and can be idled as long as you like without damaging the regulator.