PTO generator

[joshuabardwell]

You are better off with a lightly loaded genny than no load. I would always connect some light resistive loads like incendescent light before powering a critical electronic load like a computer.

You are 100% right, although for PTO generators like we are discussing here, which are often hooked up to a whole house, I think this point is moot, as there will probably always be some load, from various electronics in the house. Anyway, the computer itself is going to pull a few hundred watts maybe, so wouldn't that be good enough?

 

[fred239]

Rob-D Quote> "every ounce of fuel saved means longer run times. I say get the smallest gen set you can to do the job."

We have some smart, experienced guys here, hats off to all. Without getting in the debate, I personally beleive smaller is better, as in more ecconomical in a crisis. So how do I size for a 25hp hydraulic elevator rated at 63.5amps/208volts? My electric usage averages 8kW, but my maximum demand can be between 14kW and 21kW measured and billed monthly, including lots of constant on flourescent lighting, a big circulating pump and a forced draft boiler. An electrician told me 1.5X RkW would be enough to start the elevator, or about 20kW, although often my max demand is only 14kW in a given month. If historical max demand has been 21kW, could I get by with a 22kW 3phase genset? Fuel is precious in a crisis.

 

[SPYDERLK]

Rob-D Quote> "every ounce of fuel saved means longer run times. I say get the smallest gen set you can to do the job."

We have some smart, experienced guys here, hats off to all. Without getting in the debate, I personally beleive smaller is better, as in more ecconomical in a crisis. So how do I size for a 25hp hydraulic elevator rated at 63.5amps/208volts? My electric usage averages 8kW, but my maximum demand can be between 14kW and 21kW measured and billed monthly, including lots of constant on flourescent lighting, a big circulating pump and a forced draft boiler. An electrician told me 1.5X RkW would be enough to start the elevator, or about 20kW, although often my max demand is only 14kW in a given month. If historical max demand has been 21kW, could I get by with a 22kW 3phase genset? Fuel is precious in a crisis.

What condition does the elevator motor start under. Is it just initially driving a pump pumping unpressurized fluid, then once started the fluid is valved to drive the elevator? Or does the elevator move as soon as the motor does? ... Essentially, does the motor start under load?
larry

 

[vwnotrunning]

fred239,

You may want to check with you elevator company. The may have some type of auxillary unit (although alot slower) that may have a smaller motor just for emergency use. Depends how often you would have to use the elevator during an outage.

 

[PineRidge]

I'm not a fan of having the tractor unattended, outside while it's running for obvious safety reasons as well as coming back and finding it gone or kids playing with it. I plan on running the tractor inside the pole barn by installing a piece of flex pipe to route the carbon monoxide outside.

 

[Rob-D]

I try not to recriminate.
...larry

I didn't.
I made an observation based on an action, your ad hominem attack. If the shoe fits wear it!

 

[Rob-D]

Rob

1) Depends on the house and what he is going to run.

2) For only about +-30 years. I hook up my house generator every time I lose power. I also hook up emergency generators industrially ranging in size from a 30KW that I hooked up today (very nice Cat unit) to a 1.2 Megawatt generators that is powered by a V16 Cummins diesel engine(my biggest so far and I hated the cables they were heavy).

Really? So how much overhead did you use to calculate the generator motor starting value on your home?

Manufacturers are wrong to tell users to rate starting power at 3 times?

Here's two different sources:

Rules of Thumb:

Most generators are capable of delivering 300% of the rated current for 10 seconds, which is sufficient time for most induction motors to get up to the rated speed. So for DOL starting a generator rated 2 to 3 times the kVA of the motor will easily supply the starting kVA of the motor and for a star/delta start even a generator sized just above the rated motor kVA will be sufficient. These rules of thumb generally result in generator size that will keep the voltage dip during the motor starting within acceptable limit.

How to Size a Generator for a Motor | eHow.com

Most tools, like a circular saw or planer, require double the labeled wattage when starting. Some need three times the labeled wattage. Other equipment, such as a refrigerator that uses 800 watts, will need an additional 1,600 watts. When in doubt, provide for three times the labeled wattage for any motor.

 

[Rob-D]

What condition does the elevator motor start under. Is it just initially driving a pump pumping unpressurized fluid, then once started the fluid is valved to drive the elevator? Or does the elevator move as soon as the motor does? ... Essentially, does the motor start under load?
larry

You're a question behind:

What motor starting value would you use to size a generator in your home? 6 times? Overkill, you're wasting fuel!

 

[avc8130]

Are there any concerns with wet-stacking?

If the tractor is singing along at ~2550 rpm to maintain 540rpm at the PTO to maintain 60hz...this would be a BAD situation on a standalone diesel genset unless the generator is loaded at least 40% of capacity.

Is this "problem" non-existent on the tractor?

ac

 

[GPintheMitten]

Guys, give it a rest. You are way past convincing the other guy of anything and we ate not going to choose a winner between you. Jeesh.