Generator Need Generator Advice

[tommu56]

It sounds like the Governor doesn't pick up the load and keep speed up to the gen.
Watch tachometer when it try's to start and watch the frequency meter if you have one. and see what happens.

Make sure the tractor pto is at the 540 the freq meter on the gen should tell you that if its at 60.

tom

 

[leonz]

To leonz
I was also curious to see if any one could read what I wrote. With the soft start you can control the inrush current by time and voltage. Therefore you get a soft start. If you need a start that has to hammer the load to shift it then you would use other means. His compressors should have some unloading device maybe its not fully working.
Craig Clayton

I worked around SCR drives and they performed very well too.

I suppose its posible he has a bad/defective unloader but goosing the motor a bit more would cure the lead lag issues too.

 

[tommu56]

If it is a standard residential heat pump I think it will be single phase and I haven't seen a drive for them.

I with Craig on this one put some load on it then try the heat pump.

I would suggest you get a clamp on ampmeter fluke T5 is ok, and a volt meter with a frequency meter in it a good one is the fluke 77 IV or get the a 376 it will do it all


tom

 

[belah]

The model is a 25PTOC-3(25kW) Winco. This is what is listed on Electric Generator Direct Website which is where I bought it.

 

[SPYDERLK]

Do you have an electric hot water heater?

 

[zzvyb6]

So why isn't the breaker tripping? Seems like it would if the current draw were too high. I'd question how good the governor is. Probably too slow. If it was a startup transient problem, couldn't you add some rotating mass (like a baler flywheel) to help it through the spinup?

Here's your load factor table. It also suggests checking the brushes for clean contacts and starting off with 260 volts until you figure out the load factors. (Entire manual is on-line).

 

[dstig1]

The generator is brand new and I have #4 wire THHN running from the generator. Also, I checked the output with a meter and it's putting out 240 volts. Don't have a hertz meter.

You mean you are using 4 gauge? 4 ga sounds too small for a 25kw Gen, at least offhand to me...

 

[zzvyb6]

OK. The rest of the world says that a breaker won't trip because its not sensing instant (transient) load but loading after a heating (finite time) event. So, don't expect the breaker to help identify the cause.

What you probably need (if there is nothing else out of spec: feeder line, generator power, motor governor) is a Hard Start Capacitor for the A/C motor. This is a starting aid device that can reduce the required LRA by about 30%.

Reports show that homeowners are starting their 3, 4, and multi3 ton units off of 18kw non-pto generators just fine. So maybe you're on thin ice because of several reasons, all adding up. Can you borrow another tractor with about the same power to test the governor theory or crank the voltage up to 260v like WinCo suggests? The Kill-A-Watt device was $23 at Costco. Maybe even Wallyworld or Radio Shack has them in your area to check the frequency.

 

[mred]

Your probably going to think I am crazy to suggest this but increase the load on your generator before trying the load in question. This is actually in agreement with others on this thread but a different solution. I have seen similar behavior when starting a larger load with a 6.5K generator. If I put a larger load on the generator it is already handling some load so it does fine. Light bulbs are simply not enough try a shop vac or some other larger motor.

 

[Ken45101]

You said you have a 49 hp tractor. Is that gross HP, or PTO?

I would put a voltmeter at the A/C. See what the voltage drop is. 149 LRA is going to really put a load on your wiring and it may be that the A/C doesn't get enough voltage to get started.

It may also have a lot to do with the phase shift as the motor starts. I agree, adding non-inductive loads (e.g. space heaters) would be something to try.

Ken