Energy The different kinds of generators out there

Discussion in 'Off Grid Living' started by oil pan 4, Jul 19, 2016.

  1. oil pan 4

    oil pan 4 Monkey+++

    For your small generators there are 2 main camps out there as far as the design goes.

    Inverter generators. These vary the speed of the engine and use a 3 phase alternator to generate power, take the 3 phase alternator, turn it to DC then use a power inverter to turn the DC into 60Hz AC power. The power says a constant 60Hz.
    The inverter generators use less fuel a low load. Anything over half loaded the inverter is pretty much even with fuel consumption with the direct driven counterpart.
    You might as well just get a big deep cycle battery and power inverter at that point for powering real small items.

    Direct drive or fixed speed where the generator is directly coupled to the engine via tapered shaft or drive belt. The generator output frequency is directly related drive speed. Direct drive are normally your gas guzzling noisy generators, but they don't have to be. Around 95% of all the generators you find under 10kw will be gasoline powered direct drive 2-pole units that run 3,600RPM. The 3,600RPM part is why they are so loud and suck down so much fuel. But there are also 4-pole 1,800RPM generators and even more exotic 6 pole 1,200RPM. These can be direct drive or belt driven. The direct drive 4-pole generators tend to burn much less fuel, are a lot more quiet but cost a lot more.
    6kw 4-pole Kubota generators I work on use between .25 and .33 gallons per hour of fuel with a 2kw load.
    Belt driven generators will take an engine that cant quite turn a 4-pole generator at full out put when limited to 1,800RPM and allow the engine to turn faster, reducing the engine crank speed down from some higher speed (usually around 2500RPM) down to 1,800RPM to get the proper 60Hz out of a 4-pole generator.

    There are other generators out there besides whats at the hardware store or harbor freight but they cost a lot more.
    sec_monkey, Dont and duane like this.
  2. BTPost

    BTPost Stumpy Old Fart Snow Monkey Moderator

    If you know where to look, one can find quality 1800 Rpm Generators for less money than ANY Big Box Store screamers... No they will NOT be New, but still will outlast any 3600 Rpm Generator you buy New...
  3. Bandit99

    Bandit99 Monkey+++ Site Supporter+

    I am debating about going to look at this one (see attached photo and link). It's a 10Kw military surplus (diesel) with an Onan motor with only 50 hours on the clock: $6900. I do have some issues with buying getting it here cause my truck doesn't have a hitch for it. I have a couple of questions that maybe someone that knows military gens can answer.

    The ones I have used in the past were wired directly into the electrical panel on my civilian communication van. The military comm vans had a big huge connector that they used which I believe it military specific but on the civilian vans they had to be wired in directly, no connector. I had not planned on leaving this hooked up all the time and if I cannot purchase some connector/box...then I have no choice but that changes things and it needs to be given more thought. So, I am a bit fuzzy about connecting it.

    1. Can the normal military style cables be purchased for these generator types so I have a twist-on connector (think it's called a 'hock') at the generator and a twist-on at the house? (Then the cable could be removed in Spring/Summer, doesn't have to be buried, location of generator could change, etc.)
    2. Can one purchase a inlet box that these cables would connect to? (I have seen these cables and I know they would be horribly expensive...but they are horribly good, can be driven over by vehicles, water tight)
    3. What about purchase of Block Heaters? (I assume I can purchase a civilian kit for an Onan motor...but this is built for the military so...)
    4. Can one purchase winterize diesel in the USA or does one do it himself? (I have seen what winter does to diesel if it is not treated. What does one need to do to protect it and ensure it is useable even in severe cold weather?)

    Anyway, this is much more than I need and it would need some work to set it up to be really functional for me but if I could get it for $6000 and work through the problems then I don't think I will need to worry about a power problem ever again, stick in on blocks, build a roof over it, run some power to it for trickle battery chargers and block heaters...). Anyway, this is something I am considering...

    Fermont Mep-803A 10KW generator

    Onan 10kw generator.
    Yard Dart likes this.

    HOOLIGANS Monkey

    That is a good generator. Quiet and built for prime power duty. Do you intend to use it full time or anywhere near it's 10k ability?

    As for connecting it, I would probably try to find my way to the same point that the mil-spec receptacle is fed from and connect my feeder there, abandoning any need for military cables in favor of readily available wiring methods.

    The Technical Manual supplied with the machine (or available online) would include engine drawings and hopefully either show you where the block heater is, or at least show where it's provided for with a threaded plug (unless it is air cooled..).
    Last edited: Jul 19, 2016
  5. ghrit

    ghrit Bad company Administrator Founding Member

    For the Qs, the answer is yes to all. Your fave electrician can set you up. Don't forget the isolation breaker on the house panel. Winter fuel is a non problem; burning up the summer fuel before the changeover gets interesting unless you can drain the fuel tank.

    From the pic, it has a standard hitch, and you should be able to find the mating part on a plug that will socket into your standard trailer hitch. There are some made with keepers that will hold the ring down. I am not at all sure from the pic if that is an automatic brake on the ring or not, but you need to know, and whether you need brakes on the trailer due to the weight.
    sec_monkey likes this.
  6. Yard Dart

    Yard Dart Vigilant Monkey Moderator

    A standard pintel type hitch insert will work fine, if your truck is rated for the weight.
    Making the connections to your house wiring is simple for a licensed electrician as Ghrit said. All the mil-spec connectors and cables are available, as mil surplus, here and there on the web with a little research. You could have an exterior NEMA rated box on the exterior of your house with the quick disconnect adapter hard wired back to your house panel, no problem in general.
    sec_monkey likes this.
  7. Bandit99

    Bandit99 Monkey+++ Site Supporter+

    @HOOLIGANS "Do you intend to use it full time or anywhere near it's 10k ability?"
    No, definitely not full time. It would be used only during power outages which we have learn happen quite frequently here in Northern Idaho in the winter. Fortunately, the power company is very quick to respond but...but we were out of power for 5 days last winter, not a show stopper, but definitely a lesson to be learned for our 2nd winter here. In all honestly, we don't need 10Kw but, of course, we'll take it and won't complain while having a hot shower. :)

    "The Technical Manual....where it's provided for with a threaded plug (unless it is air cooled."
    Nah, I can't see it being air cooled at least none of the ones I have been around were and I have been around of lot of them. Didn't even think of the Technical Manual and the military ones are damn good! They would have where exactly the heater plug-in goes. Good catch! Thanks!

    @ghrit "...Don't forget the isolation breaker on the house panel."
    Yes, I got with @Kingfish a month or so ago and got the rest of the details and received the part yesterday. It's a straight mechanical interlock, cost $55 and made for my electrical panel/box. I will probably do the work myself but get someone electrical to bless it. I am good with electronics and pretty good with electrical but...better to be safe and there might be some USA standards that I am not aware of...

    "...whether you need brakes on the trailer due to the weight."
    Yes, I did think of that and need to look at it (maybe I can just call and ask) but I don't think brakes are used on them. I am betting @oil pan 4 can tell me? Also lights for it... I have a 2015 Tacoma (rated 3500 lbs trailer pull) and it has the 2"x 2" trailer slot and a round light connecter. I can purchase a Pintle insert no problem ~$80 but not sure what light connector it uses...maybe adapters are available. Dunno.

    @Yard Dart "All the mil-spec connectors and cables are available, as mil surplus, here and there..."
    Okay, that's good info. I will start searching... I just don't know these things as been out of the country for so long...

    "You could have an exterior NEMA rated box on the exterior of your house with the quick disconnect adapter hard wired back to your house panel, no problem in general."
    Yes, that is exactly the plan. The exterior box is already there that I can hook to (for which I have a mechanical interlock) so just need a inlet box so I can plug-in/quick connect. I really don't want to wire it in permanently because maybe I will want to take it somewhere where power is needed.

    I need to give this more thought but it might be money well spent. I mean the darn thing is brand new unless they fudged the hours on the clock and it could be used for so many other things but it will cost a bit to buy it and get it set up right. I am betting the cables for it cost a fortune and one needs a long cable because these are loud generators. I wrote the owner and asked if they have any cables. Researching now...
    Last edited: Jul 19, 2016
  8. Bandit99

    Bandit99 Monkey+++ Site Supporter+

    Looking at the Tech Manual, it appears this MEP-803A has terminal lugs so doesn't need any specific connector to connect to the genset itself...
  9. oil pan 4

    oil pan 4 Monkey+++

    I have worked on lots of mep generators.
    All mep series generators I have worked on will produce their name plate rated power continuously.
    I have only been working on military generators since 2003, mostly 400Hz.
    But I have never worked on one that only does 10kw, the ones I worked on that were 60Hz were all 30kw and up.
    As far as the connector goes you cant just buy one and stick it on the end of a cabel. It takes a special tool kit to assemble one. your best bet is just buying the whole cord.

    I see generators like this all the time. They can have thousands of hours on them or be brand new. If they have thousands of hours on them you can tell. If the engine is brand new and only have 50 hours it may still have its factory filters. When an engine is new from the factory the filter are painted the same color as the engine.

    Some things you may want to consider. If this generator is like the other 60Hz meps I have used it could have a 50/60Hz selector switch. Running 50Hz saves fuel. When I was powering a camp in Africa I set all the generators to 50Hz mode to save fuel and it worked since they were only being ran at 30% to 50% capacity.
    On the passanger side of the trailer there should be a small door that has a terminal board with split bolt connector and a neutral-ground bond. You can wire SO cable straight into the generator.
    Running that mep as a stand alone you want to leave the N-G bond, if you are going to power a building that is already wired you need to remove the N-G link.
    This is what the 30kw mep has, I don't know what the 10kw has.

    You see that black panel on the driver side generator door, I think that is the shipping plaque, it has the gross generator dry weight, dry center of balance and stuff. then on the trailer tongue there is another plaque showing the trailer weight actual empty weight and max weight. I have never worked on that type of trailer before but its got at least a 7,000lb axle on it. Appears to have military split rim tires that are likely 16.5 inch. For some reason the military loves 16.5 inch tires.
    They use those trailers on meps up to 70kw.
    That trailer has a hydraulic inertia braking system so you don't need a "brake controller" for the brakes on this kind of trailer.
    I would be surprised if that generator and trailer weigh less than 3,000 pounds. You should be able to tow it.
    The main concern with towing a big trailer is stopping. Remember pulling a big traler is optional, stopping is mandatory.

    On ammo trailers (not my job) I believe they like to use a 6 or 7 round pin connector. I will need to go look at one of the ammo trucks to make sure. I am sure its a common trailer connector I don't think its some special military only BS. Some how my my job does not require the trailer plug be pluged in when we are on base so I never do so I never really looked that closely at them.
    Bandit99 and Yard Dart like this.
  10. Bandit99

    Bandit99 Monkey+++ Site Supporter+

    @oil pan 4 Yep, I knew you were the guy I needed to talk to!
    "When an engine is new from the factory the filter are painted the same color as the engine."
    I will remember this when I go look at it...which I am leaning towards mainly because I know these gensets are bulletproof if they are well cared for and this is new so... What do you think of the price $6900, seems cheap to me for new trailer, new tires and new genset? How the hell did this construction company get their hands on it, new no less?!?!? The government buys new then sells at a loss?!?!

    "if you are going to power a building that is already wired you need to remove the N-G link."
    I have been reading about this today and learned a lot. If I get it I will be talking to you again about this. I assume even though you remove the bond between N and G that I will still need to ground the genset yes? I assume it's like a military 6 foot copper ground rod or the civilian world have something else, something cheaper?

    "That trailer has a hydraulic inertia braking system so you don't need a "brake controller" for the brakes on this kind of trailer."
    Whew! That is good news cause that would be a deal breaker. So, I should be able to just hook up and go, right?

    "I would be surprised if that generator and trailer weighs less than 3,000 pounds."
    Yeah...that could be a problem as my Towing Capacity is 3,500 lbs...knew I should have got the towing package or the Tundra. Wife will throw a fit if I tell her I need a new truck because I bought a generator I can't pull LOL!!!! :):) I will check the plaques because you're right the weights should be on there.

    "I believe they like to use a 6 or 7 round pin connector"
    Here's a photo of my connector for lights but I am not too worried about this as there must be adapters.

    Light connector on 2015 Tacoma.
  11. BTPost

    BTPost Stumpy Old Fart Snow Monkey Moderator

    The MEP002 is 5 KW and the MEP003 is 10 KW... These are Military Ratings... The Civilian Spec for them are 6.5 KW and 12 KW, respectively... The both were built around the Onan Diesel DJE/F Series Air Cooled Engines... But have a non-Onan GenEnd and Voltage Regulator... Rock Solid GenSets...
  12. ghrit

    ghrit Bad company Administrator Founding Member

    If the buy is worth it, rent a rig that can handle it. Your Tacoma (S10, no, Ranger, maybe, Frontier, maybe) might handle it OK with a proper frame hitch. Toyota generally under rates their stuff a bit. That said, be sure you aren't running afoul of your insurance and registration. I've registered here and there by GVW, you may have that requirement as well
    Last edited: Jul 19, 2016
    Bandit99 likes this.
  13. oil pan 4

    oil pan 4 Monkey+++

    The government always does this. They buy too much stuff or stuff they don't need and sell it off cheap.

    Yeah if the N-G link isn't remove when the generator is wired to a building the ground acts like a current carrying neutral. The generator still needs its own ground.
    Also do you know if this is a split phase or 3 phase?
    I have used a mep002 a little bit, they use variable speed alternator to power an inverter and only make split phase.
    If it is 3 phase then its likely set up for 208/120v power.
    The military is obsessed with using 4 wire wye wound 3 phase power alternators. So you will never be able to get normal 240/120 volt house power out of them. Most 240v devices will work just fine off 208.

    You have an RV connector or what some people call a flat 7 connector. This is also what I use. All I know for sure is the military trailers I have seen do not use this.

    What I would do if I was going to buy that is take the mep off the trailer since that trailer is massive over kill, sell the trailer you might be able to get $1,000 to $2,000 maybe more for it since it looks brand new. If you planed on moving it occasionally buy a lighter trailer that can take the weight of that mep. I bet that trailer alone weights between 600 and 1,000lb. A more appropriate
    trailer would weigh less than 500 pounds. My aluminum deck 4x8 trailer weighs 240lb and I bet it could hold that mep easily.
    But I like stuff to be mobile.

    Actually the generator I am building here:
    Home made generator, mig/stick/tig welder, 48v battery charger, engine starter | Survival Monkey Forums
    Some of that design was inspired by the mep002. Some of the electrical design but more of the enclosure I want to build that helps regulate the temperature of the air cooled engine and suppress generator noise. The mep002 does not weld and does not supply battery charging voltage nor does it have inverters that run off a battery.
    My idea of tactical quiet is an inverter running off battery power.
    Here is my first generator inverter hybrid build:
    Home made solar inverter generator hybrid - EcoRenovator
    I don't know if I am going to put any solar on the new rig.
    Last edited: Jul 19, 2016
  14. ghrit

    ghrit Bad company Administrator Founding Member

    Yeah, I never understood that Y arrangement obsession. That said, a transformer (extra cost) will take care of the voltage mismatch if you really want to worry about it. 208, 220, 240, all happy without it IF the gear you are running is liking it. (Ditto 110, 115, 120.)
    I have to add that 50 cycle won't make your refrigerator or freezer happy. Lighting won't care, will be a bit dimmer, but not enough to sweat over.
  15. BTPost

    BTPost Stumpy Old Fart Snow Monkey Moderator

    @oil pan 4 .... What are you saying above??? The MEP002 is NOT an Inverter Type Generator... Never Was... It was designed to replace the BattleField GenSets of Korean War Vintage, and used extensively in Southeast Asia to power Small Outposts... It is a 5Kw Military Rated Generator, built around an ONAN DJE Two Cyl, Air Cooled, Diesel Engine, turning an 1800 Rpm Four Pole, Fixed Speed GenEnd. The Genend has a 12Wire Stator, which allows it to be wired in Single or Three Phase, in 120/240Vac Single Phase, 120/208Vac Three Phase, or 277/480 Three Phase, just by selecting the appropriate Switch Settings. The MEP003 is it' Big Brother, built around the Onan DJF, FOUR Cyl, Air Cooled Diesel Engine. Also married to a 1800 Rpm Fixed Speed, 12 Wire Stator GenEnd that is Military Rated at 10Kw... There weren't any Inverter GenSets in existence until after Onan stopped building the J Series Engines in the late 1990s... The SemiConductors Required just did NOT EXIST, to make them practice, back in that day...

    Also, contrary to Populat MYTH, it is possible to make 120/240Vac Single Phase Power, from 240 or 480Vac Three Phase Power, using a special wound Transformer, and the only losses are the Transformer Core Losses, with complete Three Phase Power Balance on the primary Windings.
    Last edited: Jul 19, 2016
  16. Bandit99

    Bandit99 Monkey+++ Site Supporter+

    @BTPost From what I have been able to glean from the internet today is the MEP003 was the older version and the newer version of this is the MEP 803A. I haven't a clue what's the difference. Are you saying that this is an air-cooled unit? I thought most of the military generators were water cool but what do I know, not much. Should I be concerned that it is air cooled? Seems it wouldn't do as good a job at keeping temperature in check... What do you think $6900 too much?
  17. oil pan 4

    oil pan 4 Monkey+++

    All I know is we have a little diesel inverter. They are farily new, I thought they were called mep002. All I know is they use a 1800rpm variable speed diesel and a power inverter. I have only used them a little and never worked on one. If I ever had to look up the technical order to work on one I would know what they are called.

    There are 2 ways to get 120/240 from 3 phase. You can use a delta wound transformer or stator with a high leg winding or a Scot T transformer to convert 120 degree phases into two 90 degree phases. But good luck finding one.
  18. oil pan 4

    oil pan 4 Monkey+++

    We use lots of air cooled diesel engines in the military.
    The liquid cooled do seem to last longer.
    One of my favorites is the Hatz Z790 sometimes called the HZ790. They run for thousands of hours typically.
  19. Bandit99

    Bandit99 Monkey+++ Site Supporter+

    @oil pan 4
    'if the N-G link isn't remove when the generator is wired to a building the ground acts like a current carrying neutral. The generator still needs its own ground."
    I get it on the 'current carrying neutral' - we don't want that. And, yes, I thought genset still needed its own ground.

    'Also do you know if this is a split phase or 3 phase?"
    You are a bit above me on the 'split phase' thing - haven't a clue about it. But, here is what the seller says about output power and I did confirm it on another source on the internet: "output voltages for this unit are 120VAC single phase at 104 amps, 120/240VAC single phase at 52 amps, or 120/208VAC three phase at 34 amps."

    I can look for more on the internet and call the seller but betting this is all seller knows also. I need to look at my well pump and Hot Water Heater to see if it uses 220v but is everything else is definitely 120v...except dryer of course and I am not powering the dryer.

    I have already thought about the invertor stuff a bit... I have used a lot of 30Kw generators which powered all the satellite electronic stuff in my vans plus computer and never had a problem. Maybe the 30Kw units are filtered or have an invertor? Is the Harmonic Distortion that severe that I need to be concerned about my Flat screen TV, computers, etc.?
    EDIT: Wait! All my electronics were conditioned even my computer as I was running through Battery UPS systems, each rack of equipment had a large UPS so - I could have used any generator and it would have been okay. I forgot about that...
    Last edited: Jul 19, 2016
  20. oil pan 4

    oil pan 4 Monkey+++

    The 30kw generators I have seen do not use inverters. They are just filtered generator power.
    The main thing that will cause distortion is lighting ballast transformers and welding machines and other inverters that are plugged in and drawing lots of power.
    Sounds like I need to see what the technical order for this thing looks like. I am sure the mep 803a is loaded in our system.
    By the sound of it this thing may have both split and 3 phase windings, kind of like a welding generator.
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