auto shutdown event need help to figure out

[jl240z]

Hello Its been a few months since I have logged on as I got almost all the help I needed to install my MEP-803A by searching this forum and archives. Just before Gordon passed thru I did a startup test to make sure all was well. I had only done (2) 1.5 hr runs since I got all hooked up about 3 months ago. Heres what happened ill try and be accurate.

I connected the battery system and it started up almost on the first rev. no smoke and running smooth and normal at 60HZ/220V on the gauges. Warmed up to 180 and oil pressure at 25-30 psi. went off the main grid and turned on all the breakers in the 2 panels. I have a 400A service. The air conditioner when running pulls about 30% on the meter. The water heater went on and so it jumped to around40-50% which is normal, It went back to zero when those cylcled off. after the A/C came back on I turned on my air compressor which is 6 hp/20A No problems. and it went to almosr 70%. Compressor pumped up to 175 psi and shut off as normal.

Now the weird part, WH was off A/c still running meter at 30%. So I was using the air hose to blow the leaves off the driveway. The compressor had just kicked in and the generator started blowing solid black smoke, lost power and shut down. I tried a restart, no joy. I saw that the red breaker shut off for low oil pressure was on. Everything was normal up to that point. temp at 180 pressure at 25-30 psi 60hz/220v. I disconnected from the house and went back on the grid at that point and didn't want take any chances at that point.

I checked the oil level and it was just a hair below the full line. It hadn't gotten hot enough to affect the over flo canister. I waited about 15 minutes and restarted it and everything was normal. I read the tech manual and all I could find was it said to clean out the ends of the pressure sensor and the low pressure sensor. I didn't do the electrical checks yet as I just want to replace the two sensors or at least the low pressure sensor as this unit had at least a tier one done to it so I think it wouldn't hurt to replace them. All fluids and filters were replaced when I installed the genset. Does any one have any ideas or suggestions beyond what I have done so far? Mr Guyfang? If anyone knows you would. I also have been searching the site for a source for the two sensors. Anyone? As usual thanks for your support.

Jan Lopata
Naples FL


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[kloppk]

A while back someone posted that the Stewart Warner 279A is a replacement for the Oil Pressure sender.
Also the Sierra 18-5899
https://www.amazon.com/gp/product/B000FQ79JO/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

Also it was posted that the Honeywell 76052-15-01 is a replacement for the Oil Pressure Switch.

I'm sure others will chime in on other suitable replacements.

 

[Bmxenbrett]

I bet you just overloaded the unit. Have you put an amp meter on the set to check the accuracy or lack there of of the meter on the set?

A 6hp motor starting is a huge load. Its prob way over 20a starting.

 

[USAMilRet]

My thoughts as well. A large enough startup load that overloaded the genset causing the motor to slow dropping the oil pressure to below the trip level causing the genset to shut down due to low oil pressure. This happened to my 803a that had a broken rocker arm. Genset got overloaded and caused the oil trip to shut down the genset.

 

[DieselAddict]

+1 on the overload. You will need every ounce of energy that an 803 can muster to start a motor that size. I'm actually surprised it did it EVER, Even unloaded.

You have either a beast of an 803 or a really easy starting compressor.

 

[jamawieb]

I agree with every one else. You may have had something else on that you were unaware of when the compressor powered up. Usually when they are overloaded, the engine will smoke bad and slowly decrease in rpm's which causes the low oil pressure fault to kick in.

 

[Guyfang]

Can you run the set normally now? Will it start and run? You are assuming the oil pressure switch is bad. Assume nothing. Simulate the problem. That way you KNOW what's wrong, and don't just throw parts and money at the gen set. Start the set. Run it an hour. Everything good? Then put it under load. A resistive load would be best. Run it an hour, or more. This way, you should have a good feel for the set. If it runs this long, without problem, the simulat the for mentioned situation. Pay attention to the speed/hertz, the sound, the exhaust and notice if the oil pressure fault kicks the set off, when the engine speed/hertz gets to low to keep oil pressure at a level that keeps the set running. If the set drops RPM, then naturly the oil press switch will kick in at some point. We're the low volt and under freq lights also on? Should have been, because this is what happens when the engine speed drops to low. Simulate the problem.

oh, next time, use a better title for your thread. I read over the title 10 times, because it dosnt say a word about generators, mep-anything, aux equipment, ground power or anything else to get my attention. Even MEP problem is a better title.

 

[jl240z]

Ok will do. The generator had been running almost an hour before the shut down. I didn't think about the oil pressure going down as the load went so hi and slowed the engine down, I wish I had seen what the meter read when it crashed. The generator runs perfect after I disconnected and did the restart. The low oil pressure breaker light was the only one that was on when it stopped. I am pretty sure the A/C was the only other load at the time maybe the refrigerator but it usually shows nothing on the meter by itself. When I started the compressor the first time nothing happened. Maybe the A/C wasn't running at the time. The second time I'm pretty sure the A/C was going so based on what everyone else said it probly was an overload. What was confusing me was it didnt do it the first time I started the compressor so I wasn't expecting anything to happen like that. I will probly not ever use the air compressor during a storm outage I was just trying to put a load on the genset. I never did more than 70% before and I think that was with the A/C and the water heater so it didn't last very long. Ill do another run (without the compressor) and see what happens. I am not sure what a resistance load would be. Would that be like running the oven or the cooktop? Anything else hooked up to the house panels would turn off after a short time like the A/C and water heater. Thanks for your input everyone. Ill let you all know what happens.

Jan

 

[Zed254]

Resistive Load - think electric stove: https://www.reference.com/science/resistive-load-54135aa73b45def3

Inductive Load - think compressor motor: https://www.reference.com/science/inductive-load-ea4413eb3bcfcdd1

 

[Bmxenbrett]

Stop thinking the load meter is acurate. Its not and you havnt tested it.

 

[Zed254]

Good info on gauge calibration to get them close: https://www.steelsoldiers.com/showthread.php?171920-MEP-Meter-Calibration

As everyone has stated, a decent clamp meter and multi-meter are needed to accurately understand the amps and volts your generator is producing.