MEP 804A questions

[MikeCas]

New user with some questions on generators. First, these forums are an awesome resource. Thanks for all the good information posted here. I need a generator to run a 5 hp, 3 phase deep well submersible pump. We pump this well 2000 to 2500 hours a year to water livestock. Most of the posts I see here seem to refer to use as standby generators. Will these generators last under more than just standby usage? This pump would be starting under load. Is the MEP 804 enough generator or is it oversized for this load? It's hard to find a 3 phase generator much smaller. We have been using a Miller Bobcat 3 phase welder/generator but they are not made for continuous use like this. (Typically runs 12-36 hours at a time between shut downs). If it will work for this application, is there a way to estimate the fuel consumption? Thanks,

Mike

 

[Light in the Dark]

Welcome to SS. These generators are absolutely prime power machines, not standby. They are made to run reliably for thousands of hours, if you are mindful of proper service intervals. How many amp does the pump require? Both at startup and under use (startup can be up to 2x the draw of under use)? You tell us what it requires for power, and we can give you a ballpark idea of per hour costs.

 

[MikeCas]

Thanks for the reply Light in the Dark. I should have mentioned in my questions that this is 460 volt Franklin Electric motor. Their manual says 8.0 amps full load, max. 8.9 amps. Locked rotor amps which should be the max startup is 53.7 amps. The little Miller generator was a 10 kw and it started it just fine. I didn't ask in the first post but can these generators make the 460 volts?

Mike

 

[Zed254]

I don't think the 10 Kw MEP803A will work for you: the Equipment tag does not list 460 volts - see image.

The 804A does not show 460 volts, either. From TM 9-6115-643-10.....

8. AC Generator:
Manufacturer Marathon Electric
Type Rotating field synchronous
Load Capacity 15 kW
Current Ratings: 50 Hz 60 Hz 400 Hz
120/208 volt connection 43 amps 52 amps 52 amps
240/416 volt connection 21 amps 26 amps 26 amps
Power Factor 0.8
Cooling Fan cooled
Drive Type Direct coupling
Duty Classification Continuous
9. Governing

 

[155mm]

Ok, so your pump is 'rated' at 460v, and the pump will operate correctly in a +/- 10% window, sooo yes, you pump will run on 416, you can bump up the voltage a little, to get over the 421 mark, since the pump is the only thing running.

Your initial question was fuel consumption, My experience is 1 gallon per hour pulling less that 20% on 2 legs, my average is based on 6 days of run time. This estimate is for an 804A.

Also, I would not be scared to run one of these 20-30-40,000 hours. Like LITD said, build as a power plant, not as a standby.

 

[Light in the Dark]

Per GMG:



Edit: Gotta click on it to read it. GMG lit can be found here: https://greenmountaingenerators.com/manuals-and-support/mep-804a-mep804b-mep814a-mep814b-manuals/


Better list of lit can be found here for your machine (grab them all if you haven't yet): https://www.steelsoldiers.com/showthread.php?148936-All-the-TM-s-you-need-to-work-on-the-MEP-804A

 

[MikeCas]

Thanks to all of you for the help. I have found the links to the manuals and have the 643-10. Will try to get the others if it looks like I can buy a generator. I thought from the pictures of the placards on the machines that they should be able to start and run our pump. I also know these little diesel engines are long lived workhorses if they are treated right but I am glad to have it confirmed by someone who knows. I didn't think the 803A would work because they are single phase even if the 10 kw would start the pump. We do have some 3 phase pumps running on phase converters where we only have single phase power but if you have to use a generator it doesn't make sense to convert single phase. We like the higher voltage 3 phase because in 1,000 + foot wells you can use a lot smaller cable which is cheaper, weighs less and is easier to handle when you have to pull the pump. Now I just have to see if I can get one of these bought and shipped here.

Mike

 

[robertsears1]

In your searches, don’t ignore the MEP 804b. It has a Yanmar turbo diesel engine. The 804a has the Isuzu with a mechanical main fuel pump. I have both and think my 804b is more reliable than the 804a. I have never had a problem with the 804b and it will handle the starting of a FDECU-5 (5 ton heat pump/ac) better than the a model, which tends to show a short circuit light under the same conditions. On the a model I have also had MPU (magnetic pickup) problems, issues with the hand fuel pump, and currently the water pump is making bad noises. It only has about 140 hours while I put over 500 hours on the 804b last year.

Robert

 

[MikeCas]

Thanks Robert. I will look at 804b's too. Just had to replace a turbo in a Ram Cummins 6.7. That made me wonder if a turbo isn't just another expensive precision part to go bad. But I have had good experience with other Yanmar engines.

Mike

 

[mciikurzroot]

the 804 will make 480 with no problem, sorta, several sub systems will need to be recalibrated to avoid trip points set for the 416 range but if your up to it then its not much of a challenge, at 480 your low side will be 277 but I would suggest you set it for 460/265 then you have the easy head room within the sub sets of tolerances to make all the adjustments and your pump will not care near as much as seeing the 416 input voltage. That all said, id try the 416 set up higher as previously suggested here, it just might be totally acceptable to the well pump . it might take resetting your motor started heaters or trip point on your motor starter protection scheme, but the starting ampers will be only slightly more, as for the starting handling ability your 5 hp pump will not be any problem, the rule is 1.5 hp to make 1kw. So the 804 is rated at 15kw and will carry a 10% overload all day long, but at even 15kw the engine hp is near 23 raw hp and in actuality closer to 30hp, so starting a 5hp pump is not going to be your problem at all. now one more consideration is leave the set at 120/208 volts and use a 480/208 step up or down 10/15kva xformer and your totally set with no changes or alterations at all required, turn on and feed fuel and your all set for a long long time of reliable operation.
best: mac/mc

 

[mciikurzroot]

well hold on, the 10kw if it is a choice will run your pump as well .. please know these 803 sets also produce 3 phase with the flick or turn of a interior selector switch and your in business, then find the step up/down 3 phase xformer I mention and again your all set if you have access to an 803 or 003 even so you have good choices, if I had an 003 its a simple choice clean off the controls and up the output to 460/480 and be done with it ... best: mac/mc

 

[MikeCas]

Thanks mac/mc. Will study-up some more before I pull the trigger on a purchase. I know just enough about electricity and generators to get in trouble. I didn't know 803/003's could be configured to make 3 phase. If the smaller machines will work they may be a better choice for us than running a bigger generator only partly loaded. Thanks, Mike

 

[robertsears1]

So to recap a bit. You need 460v 3 phase to run your pump. A 804a or b ( or a 004) will get you in the ballpark with 416v 3 phase and you will need to check your motor tag to see if that is close enough. You can increase the voltage some but not sure what that will do long range to the generator. These do not have a 240/120v single phase switch. You can get single phase by using some of the legs but you have to watch about unbalanced loading that may possibly cause long term damage (the book mentions this).

Then we get to the MEP 803/003 class. These will make three phase 208/120v up to 34.7 amps (if I am reading the tag on my 003 correctly) or 120/240v single phase up to 52 amps. This class of generators does have the switch to go from single to three phase, but no high voltage option like the 004/804 class so you will need some kind of transformer. Does your pump motor have a dual votage option? Keep in mind that cutting the voltage in half will double the amps needed—no free lunch.

You can probably obtain a low time 804a or b (less than 200 hours) cheaper than a mid time (>1000 hour 003/803) since folks want to use them for home backup and off grid applications (because of the 120/240 single phase switch). The operating costs will be greater for the larger engines, so you will need to weigh all factors.

Robert

 

[MikeCas]

Robert, these motors are listed as 460V. There are other voltage options but you have to change the motor out to change voltage. And, as you said, lower voltage means higher amperage so you would need bigger cable and you would lose the advantage of the high voltage 3 phase. I need to talk to a pump expert to find out what these motor's tolerance is for lower voltage. I have about decided that I would be better off with an 804a/b than a 003/803 if I can make the voltage work. From what I have found out about transformers so far, they are not cheap. Thanks, Mike

 

[MikeCas]

One more question- If I adjust the voltage up to 460 or even 480 volts on an 804a/b instead of using other output voltages with a transformer will it cause any problems with the generator running it that way long-term? I think my pump motor is going to need at least 460V. I haven't found anything about this in the manual so far. Thanks, Mike

 

[Light in the Dark]

Whats the make and model on the pump? If the generator is designed to operate in the voltage range discussed, there will be no problems. If you try to operate outside of that range, thats where things go sideways. Per the documents I linked to before, 460 should be within the range of adjustment this class of machines can output.

 

[MikeCas]

Thanks LITD. The pump is a Franklin Sandhandler pump, 5HP, 3.7KW, 460V 3 phase, 10 GPM. Franklin Electric manual says it should draw 8A full load, 8.9A max. SF is 1.15. Locked rotor amps is 53.7. I think it was running at around 7.8-8.0 amps and 465-475 volts but I can't remember the exact numbers for sure. I am thinking that if the generator will run within the adjustment range with no issues that I should be OK. These submersible pump motors are a little different from other motors because of the small diameter for the HP. I think you have to be pretty close to spec to stay out of trouble with them. The other thing with this one is that it's on the bottom of a 1000' string of pipe that you have to pull to be able to get a look at it or change anything down hole. Thanks again, Mike

 

[155mm]

One thing to watch out for, when increasing L-L voltage, you also increase the L-N voltage alot more. If I get time this evening, I will go reset an 805 to 416 and show you what it would be.

 

[155mm]

So here is what I have, the over voltage kick on at 457v.



You can just see the corner of the screen throw an overvoltage warning when I go past 457v

https://youtu.be/dCZhFFdPovg

 

[Guyfang]

Some times technology is not always good. In the old, old days, we had in our 45 KW Stewart and Stevens gen set, an over-under box. Over voltage, Under Freq. there were two big pots on the front. If the gen set kicked off a bit to early for overvolts, you simply stuck your flat tip screwdriver in, and adjusted the trip voltage. Not so simple today.