Mep804A issues.... and single phase?

[davvy]

hello again. I got a renewed 804a isuzu motor with 3 hours on it from govplanet . When i fire it up, it does not make any voltage. If I turn the switch to start while running, it will make power then, but goes away when i release the switch. What is broken? Or do I have to have a load on it to be activated? I felt it would be easier posting here than reading TMs for a couple hours and still not knowing whats up. Thanks.

Second question, it is obviously made three phase only. However my electrician claims I can hook it up to my electrical pole after the meter at an existing generator hookup using two of the hot leads and the neutral while charging at 240 volts. It should put out the full 15kw then allegedly. Is this right, or is it off-loading the windings? I know the single phase issue has been beaten more than a dead horse here but never read if it could be done or not like this.
-Dave from South Dakota

 

[moarheavyduty]

If all you do is wire it like a traditional 120/240v split phase system and omit one of the phases - isn't the voltage potential between any of the legs only 208v? How do you get to 240? The imbalance seems inevitable and the appliances will run at reduced power or increased amperage draw. I don't know if this is a safe setup but sounds better than being without any power at all.

 

[DieselAddict]

If it stops making power when START is released the place to start is the voltage regulator circuit.

To the second question, you can’t run 15kw on two phases and not damage the generator. You need to derate it by at least 1/3. It will be 208 volts. The voltage shouldn’t be an issue for most 240v equipment. You can check the data plates to make sure 208 v is listed.

 

[Evvy Fesler]

Good morning and welcome!

Terminology flies on this forum and it gets to be confusing. Your electrician is correct. You can connect any two of L1, L2, and L3 to the panel mains, using a
circuit breaker. L0 is connected to the neutral bar in the panel.

A load, in this case the things that consume power in your house, will only consume what it needs. Rarely does a house require any more than several kilowatts at a given time. It’s doubtful that you’ll draw the full load potential from this generator unless you not only turn all of the heavy hitters on (fridge, range, A/C or heat, etc.) but also plug in shop tools, additional lights, etc. in other words, houses have the potential to draw big wattage, but they seldom do.

Each of L1, L2 and L3 when balanced will supply 5kW each. Real world loads are seldom balanced or continuous. The generator can handle this.

This is background for better understanding what happens when we deploy a generator into a use case for which it isn’t designed ro be used. We don’t have information about your load conditions to be more specific than the generalizations that have been said so far.

To answer another question. Once you hold S1 in the start position long enough to excite the main generator you can use the contactor switch to energize it. The contactor is a heavy duty relay that connects the main generator to the connection lugs L1, L2 and L3. Assuming that the contactor works you’ll always have measurable voltage on the lugs even if the lugs aren’t connected to anything. You should get 115v in the convenience outlet regardless so be sure to test it while you hold S1 in run and after.

There’s all sorts of control and safety circuits in the generator’s operating condition. Let’s hear back what you discover about the convenience outlet, contactor switch and so forth. Please post pictures of the front panel that include the gauges while running and the fault indicator lights.


Evvy-

 

[kloppk]

Test the VR per the -24 TM and post up the results of each test step.
The 804 was made with two different VR systems. Libby and TRC. Be sure to use the correct test procedure in the TM.