MP803 no power

[draymorris]

New to military gensets and to this forum.

I am trying to help a friend get a MP803 running - it has power to the contact, but it appears that the contact is not getting a signal. Can anyone give me a good starting point.
Thanks

 

[jamawieb]

Are you talking about the contactor, which takes the current from the generator to the lugs? If so, the A/C interrupter switch on the front panel needs to flipped to the closed position.

 

[Daybreak]

New to military gensets and to this forum.

I am trying to help a friend get a MP803 running - it has power to the contact, but it appears that the contact is not getting a signal. Can anyone give me a good starting point.
Thanks

Howdy,
You have come to the right place.

We need as much information as possible.

The forum already has lots of answers.

MEP-80x startup routine

MEP-802/803 Filters and Parts

and you will want the manuals

MEP-803A manuals you should have
TM 9-2815-253-24_____ Diesel Engine Model DN4M
TM 9-2815-253-24P____ Diesel Engine Model DN4M-1 Parts
LO 9-6115-642-12____ Lubrication Order
TB 9-6115-642-13____ Winterization Kit Tech Bulletin
TM 9-6115-642-10____ Operator's Manual MEP-803A
TM 9-6115-642-24____ Maintenance Manual MEP-803A
TM 9-6115-642-24P____ Maintenance MEP-803A Parts

Link to all the MEP-803A manuals

 

[Guyfang]

Have you downloaded the manuals and read the -10 Operaters manual?

 

[draymorris]

I set the ac interrupter switch to closed, but no change. Yes, I am talking about the contactor on the mains. Being new to these military units, I was hoping there was a "trick" in the startup procedure, that is why I posted such a simple post. Looks like we may have to get technical...

The battery voltage is running at 21 VDC, and there is only 18 VDC at the interrupter switch. Is this too low for the coil on the contactor? I know there are many diagnostics that can be performed, but I was looking for a shorter path.

For three years I worked on generators for a oilfield company as a contractor (a year ago it ended). In about a month I will be back to being a contract mechanic on heavy machines and hopefully generators. I know that is not a lot of experience, but you would have see my resume to see my diversified background. Not trying to say a know anything, just saying - feel free to talk as technical as you want, or not - I appreciate all help.
I know that the units I used to work on had their little problems, and within a short time I found many different parts that would fail on each brand and size and got to where I could go strait to the problem. Just looking for that potential common problem.

I read the manuals that are on the link, but did not see anything other than "set interrupter switch to close".

Any direction to go from here?

Thanks

 

[draymorris]

Will running the unit with 21 VDC overwork the voltage regulator. On one generator I worked on recently, the alternator voltage regulator had gone bad an ended up causing the voltage regulator to fail over time - theory was that it was either overworked trying to compensate for a variation in exciter voltage, or a high voltage fried a component on the AVR.
I have not tried to get the alternator excited manually yet, but will go there first if needed. The unit is about forty mile away, so I try to have as much info as possible before going back.

 

[DieselAddict]

Yea, You need to get the DC system up to snuff before doing anything else. Time to break out the manuals and do a bit of reading on how it works. The VR for the alternator is mounted on the back of it. See if the alternator itself is putting out any juice.

 

[Guyfang]

Yes, check to see if the batteries are good. Output of the alternator. The alternator is normally very robust. As Chris said, first get the DC side of the set working. It could solve your problem with the K1 contactor problem. Also know, that holding the AC interrupter switch in the up position, and hold it there for several seconds is sometimes needed. Sometimes the K1 is "sticky".

 

[draymorris]

I tried holding the switch in the closed position for longer periods. I will get the dc system working and follow up.