amdx said:
I live in Florida and have a (home) business with many chest freezers.
I'm going to purchase a generator for hurricane season.
I did have a 5000 watt generator. I stored it for three years until I
needed it.
A power company transformer failed and I didn't have power.
So I pulled out the generator and connected it to my freezers.
It worked great for about 4 hrs and it died, the field coil burned up.
This time I'll spend the money and do it right.
I want one big enough so I can run the whole house, at reduced demand,
but the freezers are the big concern.
So, (off the top of my head) I'm looking at 12000 to 18000 watt.
Need recomendations for a care free generator that will (hopefully) get
very little use, but must work 5yrs or 10 years from now.
Mike
PS. I know when I get to powering the house I'll need
a tranfer box.
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I live in the tropics in Australia, and we get cyclones (Hurricanes) here.
I decide when I moved here to put in a diesel gen set as a standby power
source.
As I have air conditioning (Several systems) and electric cooking I decide
to select a system that could run the whole house. However I eventually did
replace the cook top with a gas unit as an additional safeguard in case of
power failure, besides that I prefer a gas cook top.
The starting current of the largest air conditioning system was the main
worry, as it is 6.5 HP, that equals a starting current of 90 amps on 3 phase
415 volt power.
Our power source here is 240 volts single phase and 415 volts 3 phase @ 50
cycle, and my diesel generator supplies that power, being a 3 phase
generator.
I purchase a second hand 28 Kw air cooled diesel generator with a burnt out
generator and replaced the generator with a larger unit, 37.5 Kw (52 amps
per phase) as I was concerned about the starting current of the 6.5 air
conditioning compressor.
I knew that the diesel engine would limit the total power drawn to 28 Kw but
I was only concerned about that few seconds start up. The total power
requirement of the house with everything running does not exceed 28 Kw
In fact it is about 30 amp per phase or about 22 Kw. with everything on. I
have no problems starting the 6.5 HP air conditioning compressor, how ever
it does make the lights 'blink' a little when it starts, but I can live
with that.
As for the cyclones we had one a few years back that where we were on the
outskirts of that cyclone, and we had a power failure for 24 hours. I ran
the generator, without the 6.5 HP air conditioning unit and use 73 litres of
diesel in 24 hours, that is around 20 US gallons or 16 imperial gallons in
24 hours. At the centre of the cyclone which is some distance from us they
had power out in some areas for a month, power poles were snapped off and
lots of major damage.
--------------
This was about 7 years ago I installed the generator system and now on
refection there are some things I would have changed. These ideas might be a
help to you
I would not have size up the system to be able to cope with the 6.5 HP air
conditioning system, thus being able to reduce both the size and the fuel
needed, as if we have a prolonged blackout here the cost of the diesel would
be considerable. Twenty US gallons a day for a month would be expensive.
I could use only one of the smaller air conditioning units while there was a
blackout, thus a big reduction in both primary and running costs.
Second I think I would go for a water cooled unit, rather than air cooled as
one day a few years ago here when it was 40 c (104 f) and I was testing the
generator, with a full load, the thing shut down on a heat safety, since
then I have installed a 22 inch high speed fan to blow air into the building
where the generator is located, although it seemed pretty well ventilated
previously with those cement bricks that have large ventilation holes in
them and a large open doorway.
We have not had a 40 c degree day since to try it out, but it is running
cooler with that big fan running, so I do not think there will be a problem
in future.
I think the water cooled unit would be a bit quieter also.
I would try and buy a LPG or similar (Natural Gas ?) unit instead of a
diesel, as diesel, like petrol can go off. I have seen where the additives
for diesel can be cacogenic, so I do not use them. I have never seen where
LPG (Liquid Petroleum Gas) goes off and it is easier to store IMHO
I store 360 litres (just under 100 US Gallons) of diesel and around every 12
months use it in my Toyota Land cruiser and fill the sealed drums with fresh
diesel. So far no problems with that.
I consider it would be difficult to purchase diesel if there is a power
failure all around the town if we have a bad cyclone, as no power to pump it
out of the tanks in the ground at the service stations., hence why I carry a
fair amount
Now if we had a long power outage I would run the diesel during the day, if
the load required it, I also have a 5 Kw petrol (Gasoline) single phase
generator on the rear of my motor home which I would use instead of the
diesel unit at night for economy, or during the day if I had a low power
requirement. I do not carry much petrol, just a jerry can, but if we were
threatened by a severe cyclone I would buy some in, in preparation. I do not
like the idea of a lot of petrol being store around the house because if the
fire risk.
The 5 Kw unit could handle the window A/C in the bedroom, TV, double door
fridge and the computers with ease.
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Overall in selection of a generator, consider the starting current of the
large electric motors and remember it is possible for 2 motors to start at
the same time, increasing the total starting current.
If your generator cannot handle the starting load it can stall, or run at
low speed trying to start the motor/s, certainly not something you want to
happen as it would effect everything connected to the generator. If the
generator was running at low speed so would all the motors connected to it.
You also need to see how much is your total power requirements, plus as I
said enough to start the larger motors.
Do not wildly oversize if you select a diesel motor, as they do not like to
run partially loaded, the coke up internally.
If you are in an area that requires house heating then a water cooled unit's
cooling water could possibly be used to heat the house. For me the odd time
I need house heating it is not a thing I would spend money on.
My generators are 4 pole IE 1500 RPM (50 cycle) in America that would be
1800 RPM (60 Cycle) and I certainly would stick to 4 pole units not the
higher speed units 2 pole units (3000/3600 RPM) as everything I have read
indicates they last longer.
Hope this is some help
