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Discussion Starter · #1 ·
All,

I've looked at my generator options and I don't have anything between 2600 and 15,000w. One option that would be really handy is a 4-5kw inverter (120v). However, I am thinking a rotary that was in this range would be real nice - possibly with the ability to go all 120v or split 120/240v.

Looking at generators, engines, and options I don't like the form factor of any of the conventional open frame generators. The 15kw I have is an engine and alternator bolted to a bare steel base with 1x 50 amp connector - thats kinda what I'm after - just a bare bones set up, just smaller.

As far as engines go I like the Honda engines. If I can get an appropriately sized engine with electric start around, maybe, 10-13hp that might do the trick.

The bigger question is on alternators.

Is there such an alternator in the 5-8kw range that has a true split alternator with "2x center taps" and not just "center tapped"? I am not sure if I am using the right terminology, but what I am after is being able to phase the 2x halves together to get 120v. You can not do that with a center tapped alternator with 3 leads (2x hots and center tapped neutral) - you need 4 leads and each half physically split because when paralleling one of the neutrals in split phase mode is going to be a hot in paralleled mode, and one of the hots in split phase mode is going to be neutral in paralleled mode.

My goal is to be able to adequately run my small welder on 240v without needing the 15kw. It would be a whole lot easier to move a smaller generator, and would be a good bit more fuel efficient. The power distribution doesn't matter - if I have a 240v plug like an L14-30r for 240 and a 50a 120v like a 5-50r that is all I need at the unit.

As far as 120v goes - it would make the generator a whole other level more versatile as it would start and run heavier 120v loads that much easier (table saw, air compressor, etc). Redundancy on capabilities in the fleet is a good thing.

If there isn't a suitable off-the-shelf alternator -
How hard would it be to open one up and split it? I know alternators and motors can be rebuilt so I assume it isn't out of the realm of possibilities to get in there and split it then add an extra "center tap"? Being center tapped already that would be a pretty good dead give away where the center of the coil was = where to split.

Here is an example of something similar -

That company (Central Maine Diesel) appears to be defunct, and is actually who put my 15kw together. So I suspect trying to get that unit as a starting point to tweak to my idea I don't think is possible. I wouldn't want to try to go down the road of trying to contact them/order/lose money (already have reached out to them numerous times for info on the 15kw with no response, no biggie - I got all the service info and specs I was after through other channels). As far as a form-factor, though - the only thing different about that one and my idea is the outlets/breakers are on the end cap of the alternator whereas on my idea I want a box like the 15kw. That will be easier to do the wiring and let me put big connectors on it and a large polarity switch.
 

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Central maine diesels offerings are the only ones I’ve seen that come bare bones like that. The pictures don’t show the alternators tag clearly but you can likely get a model number from them. I remember you were dabbling with the concept of 120-120/240 voltage switches a while back. Maybe the alternators manufacturer can shed some light on its ability to reorient the windings electrically for 120v operation.
 

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Discussion Starter · #4 ·
CMD is not defunct. I reached out and got an email response from the owner ready to place an order for me.
Be careful. If you start asking questions after sale you might be met with silence. Buyer beware.

I'm not sure what you're in the process of ordering, but if it is a honda engine and mecc alte alternator you are in pretty good shape. Excellent components. However, the workmanship of the wiring etc could be questionable. If you go asking for support, that might be an issue through CMD.

The 15kw I got 2nd hand. The original owner never used it. They bought it with plans to install it, but ended up moving and then they sold it. So it sat unused (literally had 0 hours on it) for several years. Im sure its out of warranty now, but given it was a Honda engine alone and never run - I was pretty confident in what I was getting. I did not know it was a Mecc Alte alternator until after having it a while (info/spec sticker was under the bottom of the alternator, I didn't find it until later). Though, for the whole generator I paid less than the engine was worth - GX690. I can't complain and I am pretty mechanically inclined in that I do most of my own work on vehicles/engines so working on this isn't an issue.

Purchasing a new unit that is possibly in need of warranty work - that is a whole other ballgame. In that case I would spend the coin and get a Northstar or other brand. I would not touch a Generac with a 100ft pole. That might even be too close. If it has a Honda engine or a (new, not old pre-redesign) Briggs & Stratton Vanguard (2 cylinder) engine - that is probably a commercial grade generator. Other engines I would question (smaller, non- new vanguard Briggs & Stratton, Kohler, etc).

Of course, if you are going down the road of a larger prime use 1800 RPM liquid cooled unit - that is a whole other world above the "screamer class" (3600RPM, air cooled engines) generators. The same holds true with the engine work, though - whether it be Isuzu, Kubota, John Deere, Hatz, Cat, or Yanmar - the engine support will likely go through the respective engine manufacturers' support (service centers will usually be certified to work on several manufacturers' engines, aside from bigger names like Cat, John Deere, etc - they don't generally like having their dealers/techs working on competition). Unless you have a local group that services large generators (there are a lot of places that do - for the large building back-ups and peak-shaving units, in fact in several areas peak-shaving is a larger market than stand-by use), you might have to deal with engine-only work from some support groups.
 

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I ordered a GX630 and Mecc alte 12000 watt gen head from a different company, however I emailed CMD for some info on their unit as part of my research to build my own. Apparently the email on their website isn’t monitored anymore but there’s another company email that is. Don’t recall how I found it but I got a response answering my questions, albeit somewhat satisfactorily, and with eagerness to sell me a unit, so they are indeed still in business, that’s all I’m saying.
The only challenge im running into is finding the outlet box, but I admit I haven’t contacted mecc alte yet to inquire about it directly from them. Winco does sell the outlet box off of their 18000 watt vehicle mounted generator for $245 which includes one 60 amp outlet. Looking on CMD’s website their “deluxe” outlet box with 240 and 120 outlets is around a $400 upgrade, but not sure if it’s offered as a stand alone product. Figure I should be receiving my engine and gen head within the next week and I’ll worry about that after I get to overview the gen head being I’m not in a huge rush.

I can provide that email if needed
 

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Discussion Starter · #6 ·
I can provide that email if needed
If you have it send me a private message with it.

OK on the GX630 and 12kw head. That sounds like it will be a good combo. Truth be told, my 15kw was a bigger unit than I was after but it was just luck I stumbled in to it. The 12-13kw range was what I calculated based off adding up our water heater and well pump at our cabins as essential loads. The water heater is 240v and well pump is 120v. So when you break the power requirement down there is no way to "balance" the 2 loads - you stack the power of the pump on one leg of the alternator with the load of the water heater (if they are running simultaneously). So you have to add the amps up max on 1 leg, then use that higher amperage at 240v to get the wattage gen requirement. Without the actual numbers off the top of my head - 13kw was the size gen the numbers added to. However, in practice, running the whole house here with the 15kw running and AC we do have adequate power so I'm happy with that. 13kw might be a bit low. Though, that kind of power is only needed for AC or if I have a large load I need to run in the field (rare). The water loads at the cabins are rare also. Most of the time I go to my EU2200i for 120v power - its my primary unit. I just don't have anything a bump up from that right now - and that was where the thread was going - looking at a way to do a "middle ground" unit.
 

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If you have it send me a private message with it.

OK on the GX630 and 12kw head. That sounds like it will be a good combo. Truth be told, my 15kw was a bigger unit than I was after but it was just luck I stumbled in to it. The 12-13kw range was what I calculated based off adding up our water heater and well pump at our cabins as essential loads. The water heater is 240v and well pump is 120v. So when you break the power requirement down there is no way to "balance" the 2 loads - you stack the power of the pump on one leg of the alternator with the load of the water heater (if they are running simultaneously). So you have to add the amps up max on 1 leg, then use that higher amperage at 240v to get the wattage gen requirement. Without the actual numbers off the top of my head - 13kw was the size gen the numbers added to. However, in practice, running the whole house here with the 15kw running and AC we do have adequate power so I'm happy with that. 13kw might be a bit low. Though, that kind of power is only needed for AC or if I have a large load I need to run in the field (rare). The water loads at the cabins are rare also. Most of the time I go to my EU2200i for 120v power - its my primary unit. I just don't have anything a bump up from that right now - and that was where the thread was going - looking at a way to do a "middle ground" unit.
fly unless you need 240 at the cabin just get a second eu2200i gen and run in parallel when you need just a bit more power.
yea there are times a eu4400i would be nice for sure!
right in the middle range of power.
something like that would work out nice for construction.
big enough to run a saw or breaker (small electric 120 vac jack hammer)
or able to have power for an office trailer with all the tools battery chargers.

i kinda wish they would ditch the eu3000i and go a eu4400i gen!
 

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Discussion Starter · #8 ·
i kinda wish they would ditch the eu3000i and go a eu4400i gen!
I 2nd that point. The EU3000i is too small. A friend of mine runs one with his camper and it is adequate - it has head room over the EU2200i, but just a bit. Things that would otherwise just break over the capacity of the EU2200i will run on the EU3000i, but that is about all its good for.

In the case of the thread and pairing an engine with an alternator - I want it for 240v to run the small welder, but adding all 120v would make it a whole world more versatile for me. With a rotary the hit with the voltage sag on arc start shouldn't be too terrible at lower welding powers = could get by on smaller welding tasks. If it didn't have enough power at some point I could go to the big one - its just a huge jump. Not having any options in between I am not sure what would happen at what welding power, but if I can get to the low 100's, maybe 120-130a tops, welding power that would do 98% of all the welding I ever do. With that power available I'd be pretty comfortable doing away with the 15kw when I am out and about - even up north at the cabins.

Interesting to note on the welding - the technical note for generator specs on the website changed on the welder I have. I thought it was around 7-7.5kw that they recommended. Now they show surge watts at 240v being 8900w and on 120v 4500w. That seems strange. The welder is dual voltage and will drop power that you can dial it to (I want to say it is limited to 150a on 120v and will go to 200a on the dial on 240v, but the lower amperages between 120v and 240v aren't apples to apples - 100a on 120v doesn't weld like 100a on 240v). Yeah 120v is 1/2 240v, but that doesn't drop the wattage consumed in half, per se. Your welding heat has to come from somewhere.
 

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I ordered a GX630 and Mecc alte 12000 watt gen head from a different company, however I emailed CMD for some info on their unit as part of my research to build my own. Apparently the email on their website isn’t monitored anymore but there’s another company email that is. Don’t recall how I found it but I got a response answering my questions, albeit somewhat satisfactorily, and with eagerness to sell me a unit, so they are indeed still in business, that’s all I’m saying.
The only challenge im running into is finding the outlet box, but I admit I haven’t contacted mecc alte yet to inquire about it directly from them. Winco does sell the outlet box off of their 18000 watt vehicle mounted generator for $245 which includes one 60 amp outlet. Looking on CMD’s website their “deluxe” outlet box with 240 and 120 outlets is around a $400 upgrade, but not sure if it’s offered as a stand alone product. Figure I should be receiving my engine and gen head within the next week and I’ll worry about that after I get to overview the gen head being I’m not in a huge rush.

I can provide that email if needed
It would be nice to buy a panel ready to go but making your own would allow lots of flexibility and customization. Wattage meters, multiple 120v and 240v receptacles, slick battery maintainer connection, panel mounted quick connect for NG or Propane.
 

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If you have it send me a private message with it.

OK on the GX630 and 12kw head. That sounds like it will be a good combo. Truth be told, my 15kw was a bigger unit than I was after but it was just luck I stumbled in to it. The 12-13kw range was what I calculated based off adding up our water heater and well pump at our cabins as essential loads. The water heater is 240v and well pump is 120v. So when you break the power requirement down there is no way to "balance" the 2 loads - you stack the power of the pump on one leg of the alternator with the load of the water heater (if they are running simultaneously). So you have to add the amps up max on 1 leg, then use that higher amperage at 240v to get the wattage gen requirement. Without the actual numbers off the top of my head - 13kw was the size gen the numbers added to. However, in practice, running the whole house here with the 15kw running and AC we do have adequate power so I'm happy with that. 13kw might be a bit low. Though, that kind of power is only needed for AC or if I have a large load I need to run in the field (rare). The water loads at the cabins are rare also. Most of the time I go to my EU2200i for 120v power - its my primary unit. I just don't have anything a bump up from that right now - and that was where the thread was going - looking at a way to do a "middle ground" unit.

PM Sent
 

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I 2nd that point. The EU3000i is too small. A friend of mine runs one with his camper and it is adequate - it has head room over the EU2200i, but just a bit. Things that would otherwise just break over the capacity of the EU2200i will run on the EU3000i, but that is about all its good for.

In the case of the thread and pairing an engine with an alternator - I want it for 240v to run the small welder, but adding all 120v would make it a whole world more versatile for me. With a rotary the hit with the voltage sag on arc start shouldn't be too terrible at lower welding powers = could get by on smaller welding tasks. If it didn't have enough power at some point I could go to the big one - its just a huge jump. Not having any options in between I am not sure what would happen at what welding power, but if I can get to the low 100's, maybe 120-130a tops, welding power that would do 98% of all the welding I ever do. With that power available I'd be pretty comfortable doing away with the 15kw when I am out and about - even up north at the cabins.

Interesting to note on the welding - the technical note for generator specs on the website changed on the welder I have. I thought it was around 7-7.5kw that they recommended. Now they show surge watts at 240v being 8900w and on 120v 4500w. That seems strange. The welder is dual voltage and will drop power that you can dial it to (I want to say it is limited to 150a on 120v and will go to 200a on the dial on 240v, but the lower amperages between 120v and 240v aren't apples to apples - 100a on 120v doesn't weld like 100a on 240v). Yeah 120v is 1/2 240v, but that doesn't drop the wattage consumed in half, per se. Your welding heat has to come from somewhere.
cool
have you tried the mp series in the Lincoln?

it is like a 210 mp
K4195-2
and
the al spool gun
K4360-1
not sure on the stainless spool gun part number

it will do 120 and 240 vac.
if you watch the heat it will work on 120 vac ok....
but it is better at 240 vac.
at least on mig.
tig i like the 240 cord.
it stays better on power.
i also have a little suitcase inverter unit for tig on the go.
nice for when we have to weld in the meat packing house on stainless.
handy size for sure.
 

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I really like this idea. I've also toyed with it a few times.
A 3600rpm Kohler diesel hooked to a 5-6k head would do wonders for me. I'm cool with just 240v as I can always make adapter cords.
I wonder who makes Yamaha alternators? I was always curious if the brushless design is actually as good as they claim?

Sent from my SM-G973W using Tapatalk
 

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Discussion Starter · #14 ·
Looks like the smallest engine Honda makes with electric start is the GX270 at 8.5hp. I looked up some generators that use the GX270 and they are in the 4500-5500w range.

Interestingly, the generator in the link in the first post to the bare bones unit CME supposedly puts together/sells uses the GX270.

The next engine up is the GX340 & GX390 (both are 389cc) at 11hp. Generators with that engine are up around 8kw.

Looking at the wattages - the 270 is on the low side of what I am envisioning, the 340/390 is on the high end - not much middle ground.

Any thoughts?

If I had access to a generator in the range I am after that has clean enough power (that is the key - under 5% THD) to test the little welder on that would be ideal. Dad has, I believe, a Troy Bilt that is around 5500w running/6500w starting, but I guarantee it isn't low-THD and I'm not inclined to try running the welder on it just for a quick test.
 

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Discussion Starter · #16 ·
i thought they had a version of the gx200 with electric start at one time
I did notice there are kits you can get to add electric start to a lot of their engines also. From what I saw ones you can get "off the shelf" with electric start bottom out at the 270, though I didn't look everywhere so they could be out there.

Either way, though, the 270 seems like the smaller end of the spectrum on wattage ability.

I'd be curious if I sized up the alternator to, say, one rated to 7-8kw, with the smaller engine if I could limit with a breaker at, say, 25 amps, or approximately 6kw @240v. Or, if I breakered at 20a that would be ~4800w and with the delayed breaking it may take 25a spikes to handle that ~6kw for start ups.

If there was a way to parallel the alternator halves that could potentially get ~50 amps at 120v. Not sure if the engine would have the torque to maintain RPM with a higher draw.

The ideas with the smaller engine are weight and fuel consumption. If I can get adequate power that would be the idea. I suppose I will have to see what the current draw is on the small welder on the high end of my usual operating range and go from there. I haven't run it more than about 125-150a welding current, and the vast majority is under 100a. As to what draw on the power circuit that pulls - I don't know yet.

In relation to the small engine vs power output - my small open frame generator supposedly has a 5hp or so engine. I don't see the breaker amperage right off-hand, but if too much power is drawn from either the L14-30 or one of the 5-20's it will stall the engine. I've never seen the breaker pop. I'd like to avoid that - I'd like to have enough engine power to push through the breaker tripping, but not much more. Otherwise, that is wasted fuel to me. I suppose the question really comes down to what the peak wattage/amperage is that I need to hold on to with a breaker - then I can go from there.
 

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Discussion Starter · #17 ·
i thought they had a version of the gx200 with electric start at one time
I did a search on the kits and they appear to bottom out at the 160. So I did a search on the 160 with electric start and it appears you can get it equipped off-the-shelf with electric start, but it is a needle in a haystack to find one. It looks like a recoil start with a starter kit to add on might be the quickest way to get any of the smaller engines - but no guarantees there, either. Thats OK - I'm not in a rush at the moment - just looking at ideas and how to do it.
 

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Discussion Starter · #18 ·
Re: Alternators:

Looking just at wattage and THD - the following are in an acceptable range, though not directly able to be paralleled off-the-shelf (they are split phase only, can't parallel poles to get 120v only as they sit):

Mecc Alte S20W-95, 7200w, under 5% THD

The other Mecc Alte's in a similar wattage range show under 6% - too high. The S20F series (what is on my 15kw) is under 4%, but the smallest wattage version is over 10kw - probably too big to spin with a smaller engine, not sure on the shaft size compatibility, either.
 

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phase 60hz sync on a gen set is tricky at best unless it is the latest versions of the solid state inverters.
search sync to grid like they do on the BIG gen sets.
and there are several videos on you tube on this.

for me i just stick to the honda eu series of gen sets,
off the shelf item and yea you can modify them to suit your needs.
 

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Looks like the smallest engine Honda makes with electric start is the GX270 at 8.5hp.
I've got an electric start GXV120 on my HR214 mower and they worked on the smaller GX110, too... Not to mention everything from there up through the GX390 and beyond is e-start capable.
 
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