Whole house generator questions (Page 3/6)
Formula88 APR 18, 11:23 PM

quote
Originally posted by Stubby79:

Single or three phase?
(208v is three phase, not single, but OP hasn't mentioned the generators phases that I'm aware of)



208V can be either. Your typical dryer plug is single phase.
theogre APR 19, 12:50 AM
Most of China is 220v 50hz to the mains outlet. Not sure if they have single or Split-phase to a building. In the US is 220v 60hz split-phase to produce 2 120v lines 180° out of phase w/ each other in the Load Center, AKA breaker/fuse box.
Other places could be different but regardless of that, Generator should be same as normal power to the Load Center.

If Generator is setup to output 208v then many things could see a "Brown Out" condition and that can cause big problems.
Example, Most motors will have a very short life running on low volts.
Very similar to See my Cave, Electric Motors for cars.

PC and others with Switching PSU might not notice.
Other things with simple transformers likely won't run or run but with big problems.

[This message has been edited by theogre (edited 04-19-2016).]

Hudini APR 19, 03:48 AM
This is for my home in Knoxville, Tennessee. I wouldn't spend one more nickel in China that I have to live. (Plus I live in a big giant apartment building in China)



The gen head is single phase, 4 pole, 50/60 hz (1800 rpm = 60 hz), 24kw max (not sure if it's surge or continuous)

[This message has been edited by Hudini (edited 04-19-2016).]

Stubby79 APR 19, 06:07 AM
Well, at least you have a reason to have such a large generator...

Stoopid question: Is your building single phase?

[This message has been edited by Stubby79 (edited 04-19-2016).]

theogre APR 19, 12:28 PM

quote
Originally posted by Hudini:
This is for my home in Knoxville, Tennessee.

The gen head is single phase, 4 pole, 50/60 hz (1800 rpm = 60 hz), 24kw max (not sure if it's surge or continuous)


Same issue still applies.
Generator must be wire to put out 240v Split-phase to feed US Load Centers. You need more data then just saying "single phase, 4 pole, 50/60 hz" etc. If you don't have full specs then get help to find how it's wired.
If China gen set is wire only w/ 208/220/240v single phase, you may need to rewire or get another unit.
If the unit have 120v outlets you might be ok.

Important to note that Single Phase and Split-phase terms are not the same because how Ground and Neutral are connected.
Short version of split-phase wiki:

Many US poles have Only 1 HV line (13,500vac or higher) that feeds a local transformer to your house. That line is a single phase w/ earth ground for return path to a nearby substation. You see poles or under ground feeds w/ more phases but all Volts are above Electrical Ground and Neutral. (If you properly convert to DC volts all phases will be Positive Volts reference to Ground/Neutral.)

However the HV is wired... The Final local transformer has a 240v "center tap" secondary winding and ground and neutral are attach to that center wire to give 2 120v 180° out of phase w/ each other to feed residential and most commercial load centers.

180° out of phase w/ each other matter allot... That allows 2 120vac and 240vac using 2 pole breaker. If you properly convert the 2 120v lines in the Load Center to DC, you would get +120 and -120 when neg probe to meter goes to Ground/Neutral. 240 when probes goes to both "Hot" lines.

[This message has been edited by theogre (edited 04-19-2016).]

Hudini APR 19, 01:50 PM
I'm pretty sure it's the same single phase ac generator you find on each and every backup generator sold to the public. Those you find at Home Depot (not the DC to AC invertor types) have a couple 120v outlets and 1 or 2 of the 240v outlets. Makes me wonder how they configure theirs. I do see what you are saying though. Part of the reason I'm asking questions here is to see if anyone has run into this before. I will continue to seek answers as I get the engine ready. If anyone has suggestions for anything I'm all ears.
theogre APR 20, 01:44 AM
The battery to start it will need a 120v charger to stay alive.

Some bad news...
-Normal car/truck engines can, likely will, have problems for constant loads to run a generator and might not last long.
Marine/Aircraft engines are close to or same as stationary Generator engine designs.
-Most stationary units are Diesel, Propane, or NG fueled because gas goes "stale" in a few months. Maybe STA-BIL will help but read the FAQ etc. You fill and could be years before you need it.
-Check State laws... Stationary units can cause problems w/ State's "EPA." Example: Quest in Wilmington DE got problems for installing "small" Stationary Diesel unit w/o DNREC approval. Building Permits from the City where not only thing(s) needed. (small like ~ size of Fiero on side.)

[This message has been edited by theogre (edited 04-20-2016).]

Formula88 APR 20, 09:50 AM

quote
Originally posted by theogre:

In the US is 220v 60hz split-phase to produce 2 120v lines 180° out of phase w/ each other in the Load Center,

If Generator is setup to output 208v then many things could see a "Brown Out" condition and that can cause big problems.




What is called 120V in the US usually measures out to 110-115V if you put a meter on it. Same for 220V, it usually ends up closer to 208-210V when actually measured. Much like a 2x4 is not actually 2" by 4".
maryjane APR 20, 01:14 PM
Question:
Maybe I am way out in left field here but.......what is your estimated full/whole house electrical load?
IIRC the 2.8 produced 140 hp (104 kW) at 5200 rpm. You will be running your generator at 1800 rpm, which I assume is going to be direct drive, coupled direct shaft to shaft.
What HP/Kw will you have available from your 2.8 at 1800rpm and will it be sufficient to handle the full load of your electric needs?
Flywheel HP Dyno curve chart for stock 2.8?

[This message has been edited by maryjane (edited 04-20-2016).]

rogergarrison APR 20, 06:37 PM

quote
Originally posted by Formula88:


What is called 120V in the US usually measures out to 110-115V if you put a meter on it. Same for 220V, it usually ends up closer to 208-210V when actually measured. Much like a 2x4 is not actually 2" by 4".



I have a tester. In both my home and RV (generator) i get 118-119 volts at the outlets.