mep-803a question

Patiobob

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Mt. Olive NJ
Hello everyone and thank you in advance for any advice provided. I'm a new member to this site but have been reading many older posts for a while now in an attempt to get my generator running.
I recently purchased a MEP-803a generator that was in a half disassembled state. The previous owner had passed away and his wife was selling the unit. He clearly had it connected to power his home before. It came with a brand new main stator, still in the box. The guy was very meticulous about labeling every wire connection, so it only took me about an hour and a half to get the unit up and running, but it produced no power. So, assuming he ordered correct part that the machine needed, I swapped out the stator. The unit still won't produce power. I have scoured through the manuals and run many tests. Near as I can figure, the exciter rotor is bad. I am only getting 1.8 volts at terminals 5 + 6 on voltage regulator. According to manual I should have 8, some posts here have indicated 6. The bearing clearly went bad on end of gen rotor at some point and new bearing doesn't seat correctly. I've fixed that, but now think the rotor rubbed the exciter stator and did damage to itself. Not all of the leads on exciter rotor test out correctly with ohm meter. The generator stator and rotor did test correctly, so I am attempting to get some sort of power out of the unit before spending $1000 on the exciter rotor. The original main stator also tested correctly, so I don't think that was even a problem, but now it has the brand new one installed.

It did take me a while to figure out that I needed to hold start position to energize the field.

Here are my current questions: When I hold start to energize field, I can clearly see a heavy drain on the engine side of 24v electrical system. What I can't tell is what is causing that draw and where that power is being directed. The voltage regulator has no different power at any time. I've seen it actually lose power when start is held and drop down to half a volt. Only 2x out of the probably 50 or so times I've started the unit did I see the frequency hertz meter read anything. And it only did so for a few seconds then quit working. Does the frequency meter work all the time? Or only after the generator field is activated? It is more like an rpm gauge, or truly just for the electrical half of the system? The "test" for the frequency transducer has you check OHMs at the Hertz meter, so that does me no good. How else can I check the frequency transducer? The 2x the frequency hertz meter did actually work, the unit still showed no power on voltage output gauge.
I took a 6 volt lantern battery and ran it direct to terminals 5 + 6 in an attempt to create the voltage needed at terminals, and I still did not get any output from generator. One post I read here stated if the generator q1 and q2 had power sent to it, it should generate power regardless if voltage regulator is working or not. I don't have correct voltage at any terminals on voltage regulator. Not even close to correct readings on any terminals.

When I plug a drill into the convenience outlet. There is a small amount of power, but only enough to make the drill groan. I show 8 volts at the output side of the voltage regulator.
I purchased a new field flash module as original one looked toasted inside. Clearly had a burnt diode. Switching that out has made no difference. Any ideas?

One last question. There is this square box looking thing about 2.5" x 2.5" that has (had) four wires coming out of it. It seems like it was connected with, or near, the electric fuel pump somehow. It has been bypassed. It is mounted on the inside left side door, but I'm not certain that was original location for it. What should it do? The unit also has brand new 12v fuel pump in it somehow. I thought these all had 24V fuel pumps?

I've modified the generator end housing to accept a wider bearing to correct the issue the previous owner had, but would like to replace housing completely. Once I determine I can get this unit to make power, where might I be able to find the end housing? I've searched several sites and can't find anything available anywhere.

Thanks again for all your help in advance.
 

Guyfang

Well-known member
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Hello everyone and thank you in advance for any advice provided. I'm a new member to this site but have been reading many older posts for a while now in an attempt to get my generator running. (Bob, lets start with simple stuff. You got a million questions.)
I recently purchased a MEP-803a generator that was in a half disassembled state. The previous owner had passed away and his wife was selling the unit. He clearly had it connected to power his home before. It came with a brand new main stator, still in the box. The guy was very meticulous about labeling every wire connection, (When someone else makes a mistake, and then someone else marks wires, then you just repeat the mistake, when you reattach things using marked wires. ALWAYS check the wire diagram, when reattaching wires. This has happened to me a number of times.) so it only took me about an hour and a half to get the unit up and running, but it produced no power. (when someone takes something apart, there is always a chance that when he puts it back together, a couple wires get hooked up wrong. And when the person taking it apart is not the person putting it back together, then that can sometimes make it worse.) So, assuming he ordered correct part that the machine needed, I swapped out the stator. ( is there a Part Number on the new Stator? Or maybe the box? Was it open? The 400 hertz stater is not compatible to the 60 hertz Stator.) The unit still won't produce power. I have scoured through the manuals and run many tests. Near as I can figure, the exciter rotor is bad. I am only getting 1.8 volts at terminals 5 + 6 on voltage regulator. (Do you have 24 VDC on S1-7 when you hold the S1 up in the start position?) According to manual I should have 8, some posts here have indicated 6. The bearing clearly went bad on end of gen rotor at some point and new bearing doesn't seat correctly. I've fixed that, but now think the rotor rubbed the exciter stator and did damage to itself. Not all of the leads on exciter rotor test out correctly with ohm meter. The generator stator and rotor did test correctly, so I am attempting to get some sort of power out of the unit before spending $1000 on the exciter rotor. The original main stator also tested correctly, so I don't think that was even a problem, but now it has the brand new one installed.

It did take me a while to figure out that I needed to hold start position to energize the field.

Here are my current questions: When I hold start to energize field, I can clearly see a heavy drain on the engine side of 24v electrical system. (Do you mean the M4, (Battery charging meter) shows a discharge?) What I can't tell is what is causing that draw, (how big a draw?) and where that power is being directed. The voltage regulator has no different power at any time. (What places are you talking about?) I've seen it actually lose power when start is held and drop down to half a volt. Only 2x out of the probably 50 or so times I've started the unit did I see the frequency hertz meter read anything. And it only did so for a few seconds then quit working. Does the frequency meter work all the time? (no) Or only after the generator field is activated? (YES) It is more like an rpm gauge, (NO) or truly just for the electrical half of the system? (Its a transducer. It takes a 120 volt signal, and converts it to a D.C. volt signal, that that the meter reads) The "test" for the frequency transducer has you check OHMs at the Hertz meter, so that does me no good. How else can I check the frequency transducer? (hook up 120 volts AC to it. The meter should read 60 hertz) The 2x the frequency hertz meter did actually work, the unit still showed no power on voltage output gauge. (there is no such thing as a power output gage. The M1, (AC meter) takes its reading off the S8, (reconnection switch)
I took a 6 volt lantern battery and ran it direct to terminals 5 + 6 in an attempt to create the voltage needed at terminals, and I still did not get any output from generator. One post I read here stated if the generator q1 and q2 (F1 & F2) had power sent to it, it should generate power regardless if voltage regulator is working or not. I don't have correct voltage at any terminals on voltage regulator. Not even close to correct readings on any terminals (what terminals? L1-N or L1-L3?).
When I plug a drill into the convenience outlet. There is a small amount of power, but only enough to make the drill groan. I show 8 volts at the output side of the voltage regulator.
I purchased a new field flash module (what is a Field Flash Module?) as original one looked toasted inside. Clearly had a burnt diode. Switching that out has made no difference. Any ideas? ( All parts are marked with a alpha/numerical "code" to I.D. Them. There is a schematic on the doors and that should help you locate and I.D. components. That way we both speak the same lingo, when describing parts)

One last question. There is this square box looking thing about 2.5" x 2.5" that has (had) four wires coming out of it. It seems like it was connected with, or near, the electric fuel pump somehow. (pictures are worth a million bucks) It has been bypassed. (probably because it Non-Op, or someone THOUGHT it was Non-Op. Is the two plug unds still on the A9?) It is mounted on the inside left side door, (I am going to guess you mean the A9, (fuel float module) but I'm not certain that was original location for it. What should it do? The unit also has brand new 12v fuel pump in it somehow. I thought these all had 24V fuel pumps? (yes, this is a 24 volt setup. So the pump is not the right pump. Not going to say its not going to work. But think not.)

I've modified the generator end housing to accept a wider bearing to correct the issue the previous owner had, but would like to replace housing completely. Once I determine I can get this unit to make power, where might I be able to find the end housing? I've searched several sites and can't find anything available anywhere.

Thanks again for all your help in advance.
Open to see comments.
 

Patiobob

New member
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Location
Mt. Olive NJ
Open to see comments.
I'm not around tomorrow to check all these things out you just provided for me. But you have given me a great start with how to check the transducer and I'll get some photos uploaded in next few days. It has positive and negative marked terminals on one side of the frequency transducer unit, and terminals marked L L on other side. Put the 110v to the positive and negative side?
I can tell you the M4 meter shows a maxed out draw for the gauge when s1 switch is held after start or at any point when engine is running already. This unit also does not have the correct batteries in it. The previous owner put some sort of tractor type batteries and removed the full size car style batteries. It also has what is clearly a brand new alternator on the motor. It starts right up no problem, but does not have the amperage the car batteries would provide.
I'll have to check the voltage on S1-7 to answer your 24v question. I don't even know what that is, so I'll also have to look that up. I know s1 is the start switch.
For the most part this thing is labeled much like the bat cave. Everything has a name printed on it. The letters number designations are more confusing than the part reference, but I will learn the lingo to make this easier for both of us. The Field Flash Module I was referring to is the s14.
 

RHRocket

New member
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Location
California
Good afternoon I have mep-803a installed new motor and it ran for 3 hrs absolutely no problems and then out of nowhere stopped producing voltage. I have checked alot of things mentioned here and my quad field only register .9 and now I just found that stator is reisters when I check stator leads to housing
 

Guyfang

Well-known member
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Location
Burgkunstadt, Germany
RH,

Please start your own thread. You will get better help that way. When more then one person starts asking questions about different gen sets, It goes down hill quick. If you need help in starting a thread, say something. Someone will be happy to help.
 

RHRocket

New member
12
2
3
Location
California
RH,

Please start your own thread. You will get better help that way. When more then one person starts asking questions about different gen sets, It goes down hill quick. If you need help in starting a thread, say something. Someone will be happy to help.
Will do thank u
 

Patiobob

New member
4
1
3
Location
Mt. Olive NJ
Open to see comments.
I tried putting power to the frequency transducer and got a huge spark! It wasn't connected long enough to see if gauge worked, (plus I jumped 3 feet), and I wasn't going to try it again. I measured voltage instead. I've got just 5.40 volts at frequency transducer, same at terminals 7 +8. Just under 2 volts at at5+6. Somewhere around 7.22 volts at 3+4. Here is picture of mystery box. Previous owner had removed wires and labeled them. One of the wires had 12v which I used to wire in the new fuel pump. Everything was labeled with tags, (as seen in picture) but fuel pump was not labeled. Engine runs perfect with this fuel pump. I was expecting to find a step down 24v to 12v power source, (an excavator I owned had one for the radio), but I did not find anything to step down to the 12V that this wire is producing.
generator mystery box.jpggenerator fuel.jpg
 

Patiobob

New member
4
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3
Location
Mt. Olive NJ
Open to see comments.
I discovered a new possible "cause". I've spent the morning checking and double checking the stator/rotor/rectifiers/excitor/ and excitor stator. I pulled the generator cover and the excitor stator off. When I look at the stator there are 8 winding coils with the laminations. One of the coils has a square hole in it where it looks like something is missing. It had some sort of filler in it. As I went around with an OHMs meter checking to be certain nothing was grounding out, my alligator clip suddenly stuck to another coil. Upon closer examination, that coil also looks like it has a square insert in it. This one is clearly magnetic. I was able to stick a screwdriver to it. There are only two of these of the 8 that look this way. The other 6 are solid laminations and not laminated. Any thoughts? Can this magnet be inserted? generator excitor stator.jpg
 

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