220v 3phase from MEP-003

[MEPbeliever]

Greetings fellows,

I recently purchased a 10k Onan diesel genset to power my 4kw, 30amp water filtration machine that’s been sitting in my garage. The machine is from China and uses 220v 3phase power. Since I’m off grid, I decided to buys a 3 phase 200amp Siemens panel I have to power my filtration machine and another 20amp ice machine I have that uses 208-230v single phase. I talked to the company that made the water machine and they told me I should be able to use 208to power it. My first question is, do I need to bring all 4 lines L1,L2,L3 and L0 to the panel? And since I’m gonna be grounded at the gen, there is no need to ground to panel. Is it possible to feed both these machines at the same time, or do I have to switch at the generator and run one at a time? Now what puzzles me more is the fact that the water machine uses 3 hot legs and a ground and I know that a combination of any two hot and L0 gives me 208v. Why do they want three hot legs for the machine? Please see picture below. Am i thinking right or am I totally wrong here? Advise please.

 

[nextalcupfan]

I've seen where a machine will load balance the phases, for example the compressor will use L1-L2 and everything else will use L2-L3.
Also 1 hot leg and neutral will give you 120V.(L1-L0 for example)

 

[10isBestmm]

There is no 3 phase 220v. Each leg is 220v and 2 legs youd get 380v. It being a 4kw device with a 30 amp breaker suggests its actually only using 220v single phase.
That is for non usa power.

The info on the water purifier is doesnt make much sense. Id check the individual pumps, motors, and compressors to see what you actually need. Be carefull of the frequency. 50 and 60 hz is a big difference between usa and european power. Motors might not be a big difference itll just run faster or slower, but compressors dont like it.

Any component that use two hot legs or 3 hot legs typically do not need a neutral. There are exceptions, combo devices typically with a heater elements say theyre 3 phase but some equipment inside such as the heaters will actually be 3 different heaters running off different legs with a neutral.

Your devices should have seperate grounds. The ground at your generator will be your neutral-ground bond. That is not a ground.
If your running just 4 wires to a distro panel, then you have to ground the generator and the panel youre coming off of.

Some of this might be old and the code book has different ways to do it.

 

[G744]

Keep in mind, motors on 3-phase can turn either direction depending connection.

If they turn the wrong way, flip two of the three wires to reverse rotation.

Pumps or compressors really don't like being run backwards. Rotation meters are available for testing before energizing.

Said because one man's L1-L2-L3 is not always another's.

DG

 

[Guyfang]

Lots of machinery has a phase protection cuircuit. If the 3 phase wires are NOT hooked up right, the protection devise will not allow you to start up the equipment. Most also have a light. If it comes on, your phasing is wrong and the light is the slap up side the head to "remind" you.

 

[MEPbeliever]

I I was doing some research on Chinese machines and found out that R, S, T are the same as the North American L1,L2,L3. And U, V, W are the same as T1, T2, T3. This is typical 3 phase designation for European countries. If that is the case, then question becomes is the voltage regulator in the machine looking for 3 hot legs for input? , still puzzled

 

[Guyfang]

I would say yes. I thought you knew what R,S,T meant. I should have said what it was. I assume too much. Can you take a picture of the wire diagram I hope came with the machine?

 

[10isBestmm]

Size up the breakers to your gen set. If youre wiring it 3 ph 220/380 50hz for 10kw gen then thats only 20A 3 ph breaker. 3 phase 110/208 60 hz would be 30 to 50 3 ph amp breakers depending on what you could find.

 

[MEPbeliever]

Ok I’m back. I’ve been talking to the manufacturer to try to understand what really is going on here. According to them, my generator needs to provide 208v from combining the three hot lines (L1,L2, L3).Then the “supercharger” ( I call it transformer) then turns the voltage into 220v needed by the machine.
question: how do you combine the 3 lines to get 208? The switch below shows only two hot legs are used in three phase scenarios. Please explain how that would work.

 

[MEPbeliever]

Received this from the manufacturer

 

[MEPbeliever]

There is a lesson learned here. Do not buy from China. It is so hard to work things out. My manual is in Chinese. Trying to make sense of it. They are working on translating it. So I’m waiting

 

[NY Tom]

3 phase should be 3 hot legs. I don't think the neutral would be required. Just a ground.
Diagram looks like typical 3 phase connection to me. L1 L2 L3
Sounds like they are describing a buck boost transformer to raise the 208V to 220V.
We have that problem at work. 208V 3 phase power but a lot of newer machines want 230V.
Regular motors don't really care too much. Issue mainly that control voltages are too low if transformers are used to step them down.
Your 230v to 110v control transformer gives you maybe 100v or less if you feed in only 215v. When power drops to 200v you can have issues.

 

[Guyfang]

Ok I’m back. I’ve been talking to the manufacturer to try to understand what really is going on here. According to them, my generator needs to provide 208v from combining the three hot lines (L1,L2, L3).Then the “supercharger” ( I call it transformer) then turns the voltage into 220v needed by the machine.
question: how do you combine the 3 lines to get 208? The switch below shows only two hot legs are used in three phase scenarios. Please explain how that would work.

Why don't you try opening the operators TM, TM5-6115-585-12. Look under Generator Set Controls and Instruments. Scroll down to page, (PDF reader page #) 64 and start reading there.

 

[Zed254]

Page 62/234 has some good information about that switch, too.

AMMETER- ...................... Rotary switch Used to select phase, voltage and current combination
VOLTMETER ..................... for reading on ammeter and voltmeter.
TRANSFER
SWITCH

You might want to do some reading about differences of single phase vs 3 phase, too. https://en.wikipedia.org/wiki/Three-phase_electric_power is a start.

 

[MEPbeliever]

@NY Tom
I do see they use a transformer to raise the voltage. That’s how they get from the 208 to the 220 needed. If I’m going to provide 208 to that transformer, is it just a matter of connecting my three lines to the windings and turning the reconnection SW on the generator to the 120/208 position? I am going to open up that manual and get familiar with this genset

 

[NY Tom]

I can't tell you what to do here. Just what it looks like you need on the schematic.
You need to set the generator to produce 3 phase. I don't have a MEP-8xx series so best to follow the manual to select the right output. Should be pretty straightforward.
Also how you get your grounding is very important and must be done correctly for your situation.
Without the proper grounding just hooking up the 3 hots is not a safe solution.