ice storm, generators and lessons learned

[philb]

Hi Steve,
Generac makes some larger units that power critical loads in OKC. Some are >20 years old. They use a natural gas Ford engine. They seem to be very reliable. The techs told me if there is a problem its with the AVR board.

I have an old 3 phase Kohler 15kW whith a 4 cyl Wisconsin engine on natural gas or propane. It's was good but not great. The power tended to be dirty, that is, lots of harmonics. AVR boards are $980!! I've changed 2 so far and will not buy another one. Also, it went through propane like pouring water out of a bucket. 100 lb propane bottle will last 15 minutes on a 5000 watt resistive load! Diesel and even gas is much cheaper to run. I hope the new ones are better.

I'm 30 miles south of OKC and we got pea sized hail. Power was off for 4.5 hrs., which is nothing here. The grid power would have been missed if it had been off longer than a day because of well pumps and elecrtic water heaters. I did check the neighbor's yard lights to see if they have power. None. (We have 2 neighbors within site now.)

In your situation, I would consider using an inverter and forklift batteries plus grid tie at least on your freezers. If you don't need the power, you can sell it. At least the batteries would give you some backup time during ice storms. Might keep you from filling the diesel tank in the middle of an ice storm too.
Winter is still to come here as you well know.

[oil pan 4]

I work on little 5kw 900cc Kubota diesel generators that power flood lights.
They use 11 gallons of fuel over about 36 hours powering two 1000w mercury lamps.
They use 4 pole generators so they only run 1800rpm.

You could get a propane generator, but those suck down gallons of fuel even faster than gasoline generators.

[stevehull]

Oil pan - good thoughts on fuel efficiency - but gallons per hour is not the key for me. Rather, it is the BTUs needed per hour. Then find the fuel that best fits me. I don't have access to a natural gas pipeline and I do have a 250 (soon to be 500) gallon propane tank. Having a self feeding supply line is VERY attractive after five days of hand moving diesel fuel from the drums into the fuel tanks of the tractor.

Going to gasoline seems dangerous . . . pouring fuel into a hot engine happens. No supposed to, but when Mama wants power, then you pour fuel into hot engines.

Does Kubota make a larger (15 kW) 4 pole diesel generator that you like?

Thanks for the info.

Steve

[gtojohn]

How about a mechanical windmill water pump?

[gtojohn]

For grid tie micro inverters like the enphase. i have wondered myself if theoretically if i could provide a "grid" signal and make them work off grid. Outback makes hybrid inverters that can do both grid tie and battery. Those arent micro inverters though. And dang those batteries are pricey!

[oil pan 4]

The Kubota diesels I worked with were coupled to kohler 4 pole generators.

To move to a 15kw it would take the bigger 4 cylinder kubota diesel and kohler does make 4 pole generators in and around the 15kw range.
I don't know who combines the 2.

Fuel economy could be boosted by 10% to 20% by adding a turbo charger, even if you don't have to have boost to achieve power levels to drive the generator.

[simenad]

I use a PTO powered 10 kw generator but have slightly more start up loads than Generator can handle so I am adding small banks of ultra capacitors. The research so far shows that they may be replacing batteries. Some people are using them to replace/work with car batteries. They are the size of a d cell battery and have about 2.5 volts and when hooked in series work great. Even the standard capacitors would work great if your system only needs help for start up currents.

[stevehull]

Semenad - tell me more! How do these ultracapacitors work with a 240 v single phase AC well pump?

Anything that takes off the initial start up surge is very helpful.


Steve

[simenad]

Originally Posted by stevehull

Semenad - tell me more! How do these ultracapacitors work with a 240 v single phase AC well pump?

Anything that takes off the initial start up surge is very helpful.


Steve

https://www.youtube.com/watch?v=z3x_kYq3mHM

Ultracaps will work with DC current so you would need an invertor or DC well pump like those used on many off grid locations and a battery. the battery will provide the long term power that recharges the utracaps which will allow the pump to start and run for about 1-2 minutes at time. If you don't want the hassle you could wire in a couple of more regular capacitors with the pump motor control board. You may even be able to change the configuration to be like a 240 volt compressor motor that has 1 start cap and 1 run Cap. I personally like the dc well pumps with battery and ultracaps to carry you for a little while before recharging. The more DC items you have the better for power outages. They can stay charged when power is on and will continue to function when power goes out until batteries need a recharge. The ultra/supercaps are good for bigger surges without having a huge battery. Just remember that supercaps are for DC, regular caps for AC loads. They can be charged and completely discharged indefinitely, wont develop memory like batteries that use chemical storage. when used as a car battery, they will even start a car when discharged down to less than 10 volts, then recharge in about 1 or 2 minutes. do some googling. I have a 10 kw grid tied solar system but will be building a whole house back up power pack with some deep cycle batteries and ultracaps feeding my 2-5000 watt inverters. If I need more than 8 hours reserve, I can run the generator for an hour to charge all the batteries and capacitors then shut it down again for another 8 hrs or so.

[WyrTwister]

Several things come to mind . Maybe more , after I post this . So , I may have to edit it or add more posts , if additional thoughts come to me .

Fuel storage - This is a big issue . Stocks of fuel need to be rotated , to avoid being stuck with old fuel . Propane / butane is probably less subject to this than the other fuels . Since they LP gas is essentially a closed system .

Water well / pump - check into a soft start starter or Variable Frequency Drive . They would have much less starting surge . You will need to research what is avalable . Your pump motor is likely single phase . I am much more familiar with three phase technology .

I am fairly familiar with generators used in Telco applications . Both permanent and portable generators . And manual or automatic transfer switches .

We have frequently rented trailer mounted portable generators to support equipment during power cuts .

Cat | Rental Generator Sets | Caterpillar

Usually 25 kw or 45kw . Those are very nice units . They are switchable from 208 - 240 - 480 VAC and from single phase to three phase . The company I work for bought a 45kw unit last year . These units are diesel & seem to run a LONG time on a tank of diesel .

You would want or need either a manual or automatic transfer switch . Automatic is nice . It detects the power loss on utility power , after a time delay , it signals the generator to start , when generator power is stable , the ATS reansfers to generator power .

When the utility power is restored , the ATS waits a set time , to prove utility power is stable . At that time , the ATS transfers back to utility power . Either the generator or the ATS has a cool down timer , The generator engine idles a preset time to all the engine to cool down gradually .

All this can take place day time / night time . Whether you are home or not .

Of course , with a manual transfer switch , you must be there to do the transferring .

God bless
Wyr