PTO generator

[sdkubota]

Yes, I understand what you're saying but the bottom line is a gen set relies on a variable commodity (fuel) with an unstable expense and availability. So lets say it runs 1 month on your fuel supply, now what do you do?

Go Tarzan!

 

[PineRidge]

I like the idea of a 200 gallon tank of diesel but the problem is that at different times of the year the formulation changes. Here in the North that's a big deal as fuel can gel in the middle of the winter if it's a summer mix. I do use Power Products in my fuel but still I wonder. I did have fuel a few years ago start gelling in the float bowl.

I have always mixed an additive in the diesel whenever I purchase a new load. The additive prevents gelling and fungus. I have pumped and used the oil in the dead of winter and in the heat of summer without problems. Locally our oil delivery is Campbell Oil. I have never asked them but would suspect that they have a backup generator so they can continue to pump oil into their delivery trucks should a blackout happen. Perhaps if this is a point of interest you should discuss it with your local oil company.

Personally I think you are ahead of the game if you have a gen set and 200-300 gallons of oil to keep it working. Just be careful who you tell or you might have tents set up on your lawn in a power outage.

 

[tommu56]

One option is when you get a well pump pick one with little or no inrush.

Most well drillers don't have any idea of this or care about the inrush they want to sell you well with a pump in it more money in their pocket.

The grundfos pump I have at 450 ft starts and runs on a 3000 watt invertor with out batting a eye.
the quick rule of thumb if you got a cheap pump you will have a high inrush.


SQ | Grundfos

 

[Rob-D]

I have always mixed an additive in the diesel whenever I purchase a new load. The additive prevents gelling and fungus. I have pumped and used the oil in the dead of winter and in the heat of summer without problems. Locally our oil delivery is Campbell Oil. I have never asked them but would suspect that they have a backup generator so they can continue to pump oil into their delivery trucks should a blackout happen. Perhaps if this is a point of interest you should discuss it with your local oil company.

Personally I think you are ahead of the game if you have a gen set and 200-300 gallons of oil to keep it working. Just be careful who you tell or you might have tents set up on your lawn in a power outage.

I'm not disagreeing with you, I have a diesel generator but I'm working towards complete autonomy too. I mix too, but I do know that the oil yuo get in the summer has less kero in it than the winter, they do change the mix seasonally.

 

[Rob-D]

One option is when you get a well pump pick one with little or no inrush.

Most well drillers don't have any idea of this or care about the inrush they want to sell you well with a pump in it more money in their pocket.

The grundfos pump I have at 450 ft starts and runs on a 3000 watt invertor with out batting a eye.
the quick rule of thumb if you got a cheap pump you will have a high inrush.


SQ | Grundfos

What's the HP of the pump also inverters usually have 2 to 3 times overhead for several seconds. What make is yours, mine are Outback's and they have tremendous reserve, although I have 7.2kw run all day power from them without hitting the reserve.

 

[SPYDERLK]

While understandable, I'm afraid this is somewhat incorrect. A number of motors draw their locked rotor amps for a short time period at start up. Classic and common example is heat pumps. It's also true of some table saws, which has caused me joy over the years. My sawstop wired at 120 regularly trips the 20a breaker - surge is briefly 80 amps, per the engineers at the factory. Milliseconds, but still would stall out with a little 5k generator.

You can get around LRA with thoughtful staging of equipment starts - I have 3 HVAC units, and I bring them up big to small. But LRA is written on the plates for a reason (note, this is a purported advantage of inverter drive HVAC, no LRA issues)

Im glad this is finally being straightened out. All motors draw locked rotor current at startup because the rotor is stationary at that time. This is a very short term event that you will need a peak holding meter or an oscilloscope setup to capture because the current drops quickly as the motor starts to turn and continues to drop until it reaches speed. It is on the order of 4x or more of full load current. If this current times the Voltage exceeds the gen rating the gen voltage will buckle immediately. If it drops too much a motor with load wont start. A well motor starts without load , but immediately begins to develop an increasing load as it speeds up. This situation allows reliable starts at only 3x and lets you get by on a smaller gen.

Also, but not in your post, any suggestion to use 746 input Watts as equivalent to a 1HP motor will mislead the unwary. Virtually all motors use more than 1KW per HP. Actually it is a very good motor that can achieve that efficiency. And, as above, even a lightly loaded 1HP will still exhibit the high locked rotor initial current 4x above nameplate. Should this cause gen V to buckle it will cause big problems with other motors that may be running. Refrig or AC compressors may stop and take down the system. Multiple motors running simultaneously and cycling on gen power are going to cause an issue with systems not having ample surge capacity. Thats why its so good to oversize the gen while sizing the engine to supply the running load. The gen doesnt buckle and inertia controls V drop thru the surges of startup loads.
larry

 

[zoltanthegypsy]

At our house, we end up on generator power for several days/weeks a year When we rebuilt our well and storage system we went with a Grundfos SQE variable-speed storage pump in part because of the lower generator load during start up. Here's what Grundfos says, FWIW. Sorry about the formatting.

11. Generator operation
It is safe to operate the SQ/SQE with a generator. The generator must be sized 50% above the P1 (input power) values of the pump. See the following table.

Motor [hp], Min.generator size [W], Recommended generator output [W]

0.5 1200 1500
0.75 1900 2500
1.0 2600 3200
1.5 2800 3500

[edit] Just noticed that tommu56 has already mentioned the Grundfos option. Sorry about the noise.

Z.

 

[fred239]

My 50kw Winpower is no typo. It could punch out 50kw continuosly with the JD 4020. My F-935 is/was 22 hp when new. But, my demand is not 50kw, its probably less that 6kw. No matter, the F-935's motor can deliver enough kinetic energy for the Winpower to convert it to electricity for my use. If my demand was for a higher electric power than is equivalent to the 22 hp on the mower, then it would brown down. Or I could throw my JD 1070 back on (35 hp) and see if that's enough motor (18kw load). But the alternator is wired to handle the current equivalent of 50kw service in case I need to run a small town. Then I would need the 4020 (100 hp?) to deliver the equivalent engine hp.

When I bought the Winpower at a farm auction, all the buyers were told it would take 100+ hp to run it. But I was not going to dry corn, I wanted a furnace, well, lights, fridge, TV/radio and a battery charger. So I was the only one who bid after a lot of discussion and opinions by the know-it-alls : $600. I can still hear the auctioneer yelling: "SOLD. The auction is today folks!"

Congrats on the wise purchase. I'm still looking and trying to figure the most cost effective solution. Modern specs show that gensets are most fuel efficient at full load in terms of fuel consumed per kWhour of electricity produced. Just wondering if you have measured fuel consumption vs. load? At what point can we burn natural gas @$0.40/Therm and sell electricity back to the grid? What is the maintenance cost to run a big generator 24/7/365? Can a 100kW unit be maintained for $8760/year or $1 per hour? I know these are not "PTO" questions, just thinking, natural gas is darn cheap these days.

 

[sdkubota]

I just purchased a 15kw Rural King pto generator for my 35 hp, L3400. I ran it the other day and couldn't believe howeasily the tractor handled it at the 540 rpm level. I wasn't at full output by any means on the generator but the tractor wasn't working hard at all.

 

[techman]

At what point can we burn natural gas @$0.40/Therm and sell electricity back to the grid? What is the maintenance cost to run a big generator 24/7/365? Can a 100kW unit be maintained for $8760/year or $1 per hour?

You will have trouble finding a genset that big that runs on NG. There are a few that use car engines, but you are mostly into diesel at that power. Unlikely that you will ever match the utility prices since they too are switching to NG at much higher efficiencies in generation.

paul