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My MEP-803A

csheath

Active member
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Location
FL
I completed the digital meter install but I still have to troubleshoot the voltage drop on L1. Overall I am pleased with the digital meters. I have always prided myself in figuring out the easiest way to do most things I attempted but as I age I seem to have more do overs and after thoughts when I do some things.

The volt/hertz meter reads 4 volts low but the hertz reading is dead on and that is mostly what I needed. The volt/amp meters are dead on with the voltage readings but the amp readings may be a tad low. Any way you cook it the information being supplied is way more accurate than the analog gauges the unit had on it.

I wanted all the information to be in the same location so I replaced the old voltage gauge with a volt/hertz meter and placed both volt/amp meters in the hole where the previous load percentage gauge was.

The volt/hertz meter was as simple as cutting a plate the size of the old gauge face, cutting a 1-3/4" hole in the center of that, and punching holes for the new meter and old gauge patterns. For connection I just trimmed the eyelet connectors so one leg would go in the new meter connection.

IMG_1396.jpg IMG_1397.jpg IMG_1398.jpg

The volt/amp meters involved making a plate they would snap into and cutting the old percent gauge hole square. Here is a place I over complicated things. I used the existing screw holes for the plate and filed the screw heads and nuts for clearance. In hindsight I should have drilled 4 new holes to mount the plate and new meters to the generator control face. I had to cut a hole behind the control panel to the load lug area for the wires. The floor in this area is two panels thick so you need a grommet that will accommodate that. I didn't have one but trimming the edge around the thin panel grommet I had seemed to work okay. I used 16 gauge speaker wire to connect these. I have tested the insulation on this and it holds up under heat as well as any high quality automotive wire I've seen. I wired a whole racecar with this stuff and it worked and held up fine.

IMG_1400.jpg IMG_1401.jpg

Here is the final results.

IMG_1402.jpg


Back to this voltage drop issue. If anyone has any suggestions on this I would be glad to read them.
I set the initial unloaded voltage to 124V on each leg. This matches the unloaded voltage at the panel in my home. I applied loads incrementally and read the voltage at each leg and the hertz drop on the volt/hertz meter. I set the hertz to 61.5. Below are my results and I feel the voltage drop on L1 becomes critical and not something I want to run my house with. The hertz drop is within what I consider safe but I may try to adjust the droop to get that little tighter. My load bank only uses 240V loads so the results should be dead even. The only thing uneven is I use the convenience outlet to power the fan on my load bank but it draws less than 1/2 amp. During the tests L3 remained or recovered to 124V on each load change.

2700W L1 dropped to 121V
Amps at 11 on both legs.
Hertz dropped to 60.7

5400W L1 dropped to 118V
Amps at 19.5 on both legs
Hertz dropped to 60.1

8100W L1 dropped to 116V
Amps at 29.9 on both legs
Hertz dropped to 59.6

10,800W L1 dropped to 113V
Amps at 38.7 on both legs
Hertz dropped to 59.4

13,500W L1 dropped to 109V
Amps at 48.8 on both legs
Hertz dropped to 59.1

L1 connections are tight on both sides of the load lug. I will have to remove the top to get to the next junction on that. I have cycled the phase selector switch and AM/VM switch multiple times and haven't seen any change.
 

DieselAddict

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The way to troubleshoot this is to measure the voltage across each set of windings in the alternator. You can do this at the phase selector switch.

Let me know if the TM (schematic) doesn't make sense as to where to take the measurements.
 

Haoleb

Member
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Raymond, Maine
That speaker wire may hold up to heat fine but I would be concerned about the dielectric properties of the insulation on it. I mean yeah, it is probably fine but personally I would feel more comfortable with something like 1000v MTW in there if it was my set.
 

csheath

Active member
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43
Location
FL
Looks like I'm about to write the final chapter on this project. I tried tightening some connections to cure the voltage drop and didn't have any results doing that. Sooooooooo I started taking connectors off, sanding, deoxidizing, and recrimping. I also sprayed some deoxidizer in the phase selector switch and exercised it some more. I did all the L1 connections at K1, S8, and TB3. When I started it back up I readjusted the voltage to 124V on each leg. When I applied a 20 amp load L1 dropped to 117V again. I decided if it didn't go below 110V with a 40 amp load I was going to give up and not worry about it. Low and behold when I put another 20 amps load on it the voltage shot back up to 124V and hasn't dropped since.

My hertz droop was within the specs but I tried to tighten that up some. I made 3 adjustments resulting in 2 turns of the screw and only changed the droop a little. I didn't want to keep cranking on that so I adjusted the no load hertz to 61. It drops to 59 with a 40 amp load applied so I'm calling it good to go.

Now I need to order some 10-32 screws and nuts since half of those broke on removal. I will get the 55 gal drums filled and set myself a monthly test reminder in my phone calendar.

Thanks to everyone for their help and suggestions.
 

DieselAddict

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Electrical problems generally don't heal. You should keep an eye on it. Something may have arced and made a "better" connection for now. Unless you find a positive reason for the imbalance don't fully trust it.
 

csheath

Active member
714
213
43
Location
FL

csheath

Active member
714
213
43
Location
FL
Just completed my first monthly inspection and everything passed with flying colors. I set the reminder in my phone calendar for the 2nd Sunday of every month.

I began by connecting the ground bonding strap and checking the output lugs for tightness. I plugged my load bank into the RV outlet I have installed on the side of the unit and plugged the fan for that into the accessory outlet.

BTW if you have the wrench that came with these it is much more useful if you cut a couple of inches off the handle. Makes it easier to put in and out of the holder too.
IMG_1417.jpg IMG_1418.jpg IMG_1419.jpg

After checking fluid levels I fired it up and ran it a few minutes with no load till it got to temperature. Then I applied loads and ran a few minutes at each setting starting at 10, then 20, then 40, and 50 amps. After running at 50 amps a few minutes I dialed it back to 40 and ran it for two hours. Then I backed the loads off and ran a few minutes at a each setting till I had it back to no load. Ran it a few minutes to cool down and shut it off. The voltage remained constant on both legs and the hertz droop under load was acceptable.

IMG_1424.jpg IMG_1421.jpg

I wanted to do another test of the auxiliary fuel pump and also make sure it would pull fuel from my 55 gallon drum. I had filled the tank with highway diesel and had it so full the gauge was pegged at the start and was reading just below the full line after 2-1/2 hours. I used an external pump to pump most of the fuel out of the tank into my 55 gallon storage drum. I used 35 gallons out of it the other day so I had room. The fuel in the generator had not been treated so I added a little extra Killem biocide to the drum. Then I connected the hose from the drum attachment to the generator and turned the switch to the AUX position. It was taking so long to fill the generator tank I went ahead and restarted the engine to keep the batteries charged as the auxiliary pump worked to fill it back up. I checked a few minutes later and found the fuel gauge reading right under the full line where it was after load testing. I felt the fitting on the auxiliary hose and it wasn't pulsing so that pump had shut off as it should.

I finished up by disconnecting the ground bonding strap, checking for leaks, and checked the oil level again. All is good.
 

Haoleb

Member
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18
Location
Raymond, Maine
Good idea with cutting the wrench. I bought one for my unit off ebay and when I used it I thought to myself.. Hmm.. Really? It does the job but at 1/10 a turn at the time. I may shorten it like you did.
 

Guyfang

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This is one of the first things anyone does to the set. First take the wrench off the rope, and second, shorten the wrench a few inches.

It's difficult for me to understand why the wrench is non conducting. Why, oh why, would anyone stick their hand down into that tiny little door, using a wrench too long, attached to a rope too short, and three live terminals just a few inches from your hands. Sorry. Even if I consumed several bottles of good Joey Crow tequila, this brilliant idea would never come to fruit. Shut it down, tighten the lugs, start it up. Now that I think back a bit, I have tightened up the output lugs, with a rope too short, a wrench too long, while powering a system. My only excuse, is youth and beer.

To add insult to injury, the clips are destined to fall off as soon as you begin to fumble around with the wrench. Got to find them, in the dark recesses of the bottom of the set, and get them back on, IF you also have the small cross pieces. At a later date, that just never seems to come. And if the set is not mounted on a PU set, then you have to do all of this on your hands and knees. With a flashlight stuck in your mouth.
 

csheath

Active member
714
213
43
Location
FL
This is one of the first things anyone does to the set. First take the wrench off the rope, and second, shorten the wrench a few inches.

It's difficult for me to understand why the wrench is non conducting. Why, oh why, would anyone stick their hand down into that tiny little door, using a wrench too long, attached to a rope too short, and three live terminals just a few inches from your hands. Sorry. Even if I consumed several bottles of good Joey Crow tequila, this brilliant idea would never come to fruit. Shut it down, tighten the lugs, start it up. Now that I think back a bit, I have tightened up the output lugs, with a rope too short, a wrench too long, while powering a system. My only excuse, is youth and beer.

To add insult to injury, the clips are destined to fall off as soon as you begin to fumble around with the wrench. Got to find them, in the dark recesses of the bottom of the set, and get them back on, IF you also have the small cross pieces. At a later date, that just never seems to come. And if the set is not mounted on a PU set, then you have to do all of this on your hands and knees. With a flashlight stuck in your mouth.
Yeah I have everything tightened and connected and the door shut before starting. Only if I need to verify voltage, amps, or hertz with a separate meter would i operate with the lug door open. Now that i have a digital reading that was verified I have no need to run the unit with the door open.

Oh, and I took all the clips off and chunked em. I went ahead and tightened the unused L2 nut down so it won't vibrate off.
 

csheath

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43
Location
FL
Just performed my 3rd monthly test and all went well. Ran it for two hours with a 40 amp load and it purred like a kitten. Checked oil and coolant levels before and after and frequently looked at the gauges and meters as the test ran.

I did commit some operational errors but I don't think they were serious. First I always forget to hold the start position till it registers oil pressure so I had to start it twice. It fired right up on both attempts and of course it remained running on the second try. I also forgot to reconnect the neutral to ground bonding strap. Not sure if it's that important because my load is only connected to L1 and L3. I do have the machine grounded. I had put a note on my load bank as a reminder but it is covered in pollen so I didn't notice it. I will probably put a tag on the fan plug so I will have to notice when I go to plug that into the convenience outlet. Last I forgot to toggle the interrupt switch off before shutting the engine off. Again, I'm not sure if this is important. I had all the load turned off before shutting it down. I always pull the load in increments and let it run a few minutes with no load before shutting it down.
 

Trick1us

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can anyone show me how to use the lug terminals and the earth ground i have a nema 14 cable to my house from my old generator and just bought a mep 803a and want to load test it using my existing hookup
 

DieselAddict

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can anyone show me how to use the lug terminals and the earth ground i have a nema 14 cable to my house from my old generator and just bought a mep 803a and want to load test it using my existing hookup
that is not recommended. You should not connect the generator to your house until after it has been properly tested with a load bank. You will be putting expensive stuff at risk.
 

csheath

Active member
714
213
43
Location
FL
can anyone show me how to use the lug terminals and the earth ground i have a nema 14 cable to my house from my old generator and just bought a mep 803a and want to load test it using my existing hookup
As stated you should load test the unit before connecting to the house.

If your cable plugged in to your old generator with a NEMA 14-50 male plug then the easiest way is to get a Temporary RV outlet and mount it on the side of the generator. Using 6 gauge wire connect L1 and L3 to the hot lugs, neutral to neutral, and ground to ground. You should drive a ground rod near the generator and connect a wire to that as well as the outlet ground. Assuming the cable is running to your house panel and that panel has the ground to neutral bonded you would remove the strap bonding the ground and neutral on the generator.

Here is a photo of my homemade load bank connected through the RV outlet. FYI I bonded the neutral and ground in my load bank panel so I don't have to connect and reconnect the strap in the generator when I perform my monthly test. Make sure you understand the methods and consequences of improperly bonded grounds before you do anything.

IMG_1373.JPG
 
Last edited:

Daybreak

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can anyone show me how to use the lug terminals and the earth ground i have a nema 14 cable to my house from my old generator and just bought a mep 803a and want to load test it using my existing hookup
Howdy,
You have found the right forum. That's good.

Keep reading stuff in the forum. There is a lot of knowledge which has already been hashed out.

The reason why you do not want to just hook it up to the house is...

You need to verify it functions properly.
Use a multi-meter to verify you have a good 120v on L1 and L3. and a good 60Hz.

The convenience outlet is only good for 10amps. The reset for it is behind the control panel, right to the left.

After you have checked it all out, start going over what your connecting to.

I would suggest that you have all your breakers off, and turn on 1 breaker which does some plugs. Put your multi-meter there and check again for a good 120v 60Hz.

Now your good to go. :cool:
 
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