10 kw generator mep 803a

[jbk]

a couple of past threads dealt with problems similar to yours on the 803 and they had bad master control switches. i think they found replacments on ebay. i looked and i have the operators and parts manual only.

 

[bullwhacker]

a couple of past threads dealt with problems similar to yours on the 803 and they had bad master control switches. i think they found replacments on ebay. i looked and i have the operators and parts manual only.

Thanks,
Where can I find the switch besides eBay?
Also where can I find the wiring diagram or info as to the master switch's terminals where they go to?

 

[LanduytG]

Sounds to me that you have the operators manual. Here is a link to the big manual http://www.liberatedmanuals.com/TM-9-6115-642-24.pdf . I suggest you put this on a thumb drive and take it to a place that can print the wiring drawings onto 11x17 paper, pages 276-281. Makes working with them much easier. The TM also has test procedures etc. Military manuals IMHO are about the best TM's written. Very easy to follow even if your not real familiar with the unit.

Greg

 

[bullwhacker]

a couple of past threads dealt with problems similar to yours on the 803 and they had bad master control switches. i think they found replacments on ebay. i looked and i have the operators and parts manual only.

Thanks,
Would you recall where those threads are or were?
Just in case I have started to look for another master switch; but if I can't find one maybe I have to install a set of switches to energize and prime then start.
Looks to be four - One momentary contact for glow plug; one on/off for aux./prime/run; one on/off for prime/run, one momentary for the start. To shut down turn the prime/run off?
Seems to shut down when you turn master switch to off it cuts power to the fuel pump?

 

[bullwhacker]

Sounds to me that you have the operators manual. Here is a link to the big manual http://www.liberatedmanuals.com/TM-9-6115-642-24.pdf . I suggest you put this on a thumb drive and take it to a place that can print the wiring drawings onto 11x17 paper, pages 276-281. Makes working with them much easier. The TM also has test procedures etc. Military manuals IMHO are about the best TM's written. Very easy to follow even if your not real familiar with the unit.

Greg

Thanks for the info. It helps allot.

 

[bullwhacker]

I just printed out the manual at the link I was given. WOW 27.6 gig buffered/spooled 293 pages.
Printer laser can print both side. When it was done I'd swear my printer gave me the middle finger..

 

[lindyp38]

id like to install a battery maintainer for my generator....any suggestions? has anyone done this?

thanks

 

[Rapracing]

I am not familiar with the 803 but I believe they are 24v? If so I am using this. [h=1]Pulsetech Solargizer.
Model: IS-24-L[/h]I got them new on the auction site for $50 shipped but they are down to $40 right now. I think they are a discontinued item but they have served me well.

 

[kloppk]

Regarding the Fuse Mod...
Here is a link to TB 11-6115-741-24 that has the original info on the Fuse Mod, Generator Tier Resets etc.
https://www.logsa.army.mil/etmpdf/files/080000/082917.pdf

A bit more information after looking into this. The fuse mod is done to protect the generator head should the bridge diode in the Voltage Regulator short out.
It does not protect the voltage regulator from being damaged, it only protects the gen head after the regulator has shorted out.
If doing the fuse mod I'd also recommend adding a Metal Oxide Varistor (MOV) across terminals 7 & 8 of the voltage regulator.
The MOV will protect the regulator from being damaged.

 

[m-35tom]

So since the regulator board is easy to access, the diodes should be replaced with ones with a higher PIV and a MOV installed for future reliability.

 

[m-35tom]

upon reflection and some research i conclude the MOV will do nothing to help. if the starter is engaged and under 900 rpm, the flash circuit is on. prolonged cranking is the problem, so the fix is to repair whatever is making it hard to start. all of mine start in just a few seconds so the only issue would be replacing the diodes for regulator reliability.

 

[zarathustra]

I'd love to take a peek at a new-off-the-line voltage regulator to see what and if the vendor did anything about this problem. There is another issue besides this that the vendor needs to address on these regulators and I'd like to see how they dealt with that as well.

 

[m-35tom]

the part number on mine is 19580 but on the board is 19583 so this may indicate a redesign. what other issue do they have?

 

[zarathustra]

I don't have the board with me -- I'm going out to the shop later today and I can get the number then. The regulator I have is from around 2000, so I don't know what version it would be. There is, however, a fifth power diode (that is not part of the bridge circuit) and a capacitor that are betwen pins 5 an 6. They don't seem to serve any purpose, but the capacitor would absorb spikes, and if the diode reverse voltage exceeded 400 v it would short and stop the generator from generating any AC at all, perhaps preventing a runaway situation on the Q1/2 side...

The second, and perhaps the most important issue in the long run, is the issue of the two MOSFET transistors on the board...

They are obsolete parts, and can no longer legally be manufactured for use in the US or in Europe 'cause they violate some EPA rule -- the MoHS rule. One can still buy them, but the inventories are probably being liquidated with no new ones coming down the line.

Since these generators are still in production, Clearwater must have redesigned (probably tweaked) the regulator to get rid of those MOSFETs. They will likely use a new MOSFET; one that complies with MoHS standards. That is why I am keen to at least look at a brand new one to see what changes were made, if any to get rid of the 450 series MOSFETs and hopefully deal with the bridge rectifier, Q1 Q2 problem.

It is almost ( I said almost) worth the price of a new one just to see the new board, assuming if one purchased a new one that it was indeed, new manufacture and not NOS

z

 

[m-35tom]

Z, I think the newest of my herd is a 2009 and I checked the Q1-Q2 voltage and it never went over 94 vac while cranking. I was just holding probes on the terminals, but will make some pigtails to check the voltages more accurately later. There are some labels, rand written in some other gens so maybe some other mods are being made as well.
tom

 

[zarathustra]

It is easy to take the unit apart. I have mine apart, and I'd attach a picture, but any time I try to do that my computer locks up in the 'manage attachments' screen and I have to remove the battery to get it to shut down.

If you do take it apart, note the number on the MOSFETs. Mine is IRFP450 which is the obsolete number. If your number is different that means that they have tweaked the board for the new MOSFET and possibly the Q1/2 problem.

 

[m-35tom]

ok, so this is what i find on a 2006 unit. If I disable the fuel so it will not start and crank it, the quad connection to the reg has 0 volts. If I allow it to start the voltage never goes above 64 VAC while the field goes to 40+ volts while starting, but not while cranking, it is after the starter shuts down at 900 rpm. Then the field is adjustable from 4.3 to 8.8 VDC. There are two paper lables inside on the right of the reg, one says FS-10, the other 88-20032 and a date. 88-20032 is listed as CONTROL, MOTOR GENERATOR says it has an aluminum case, I don't yet know what it is.

 

[m-35tom]

I came to the conclusion that 88-20032 is the entire control box assy with all it's contents

 

[kloppk]

I did some peak voltage readings with a digital scope on the quad circuit of my 802A (regulator pins 7 & 8 )during cranking and running.
The worst case peak AC voltage was ~90 VAC just as it started to run and the quad voltage settled to ~70 VAC while running.
I plan on installing the MOV.
Should I ever encounter a long cranking situation I'd rather have the MOV do it's thing and blow the 3A fuse than to wipe out the regulators bridge rectifier due to the high PRV.

 

[m-35tom]

90 PIV is nothing and I don't see how it could ever do any harm. Installing a MOV is just a waste of time and could even be a hazard. A MOV only reacts to spikes of milli second duration, not at all to steady state voltages, so the best thing it would do is over heat and catch fire. What year is your gen? I think it looks like after some point the circuit was re designed. I have heard of voltages in the 400 V range, but I am not seeing them on newer gens.

I also have to wonder if the 'input power' (3 + 4) and the 'quad' (8 + 7) are not misunderstood. In a 3 phase gen with an unbalanced load like this could be in single phase, it is very hard to have a voltage regulator since the load could be high on the windings you use for referance voltage so the reg would send the field more voltage. If that winding comes up to correct voltage, other windings with less load will be too high. To avoid this you have a seperate winding with no load, like the 'quad' winding, and take your ref voltage from it. Then you have the input power to run the reg from some other coil, it would not matter which. Apparently, however, the diodes that fail are in the quad circuit, I do not really understand why yet, I would think the reg would get it's DC voltages from the input power.