Hi

I live out on a remote farmhouse whose electric is supplied on overhead
electricity
poles.

In the two years that I have lived here, I've had about 20 power cuts.
Some are only a few minutes and a nuisance, but others can last for a
few hours.

I have lots of space outside, and a space ready for a power generator
(petrol/deisel etc).

I have a couple of questions though.

- How do I calculate the power (watts) that an appliance requires?
- Is there a device that can measure the power requirement for an
appliance, or for my entire power requirement (I have an economy 7
dual dial meter)
- When my power is initially connected after a power outage, all of the
outside floodlights come on and create an initial surge. How would a
generator cope with that?

I am assuming that once I have worked out my power requirement, I will
need to find a generator large enough to cope with it.

I would be happy if the generator would power a lighting circuit, and
maybe a few appliances (heating pump, boiler, television, radio etc).

Any experience/tips/advice would be greatly appreciated.
Thanks

Charles

On 17 Jan 2005 06:38:06 -0800, "Charles"
wrote:

Any experience/tips/advice would be greatly appreciated.

Post this to uk.rec.engines.stationary _Lots_ of experience in
there.

"Charles" wrote in message
oups.com...
Hi

I live out on a remote farmhouse whose electric is supplied on overhead
electricity
poles.

In the two years that I have lived here, I've had about 20 power cuts.
Some are only a few minutes and a nuisance, but others can last for a
few hours.

I have lots of space outside, and a space ready for a power generator
(petrol/deisel etc).

I have a couple of questions though.

- How do I calculate the power (watts) that an appliance requires?
- Is there a device that can measure the power requirement for an
appliance, or for my entire power requirement (I have an economy 7
dual dial meter)
- When my power is initially connected after a power outage, all of the
outside floodlights come on and create an initial surge. How would a
generator cope with that?

I am assuming that once I have worked out my power requirement, I will
need to find a generator large enough to cope with it.

I would be happy if the generator would power a lighting circuit, and
maybe a few appliances (heating pump, boiler, television, radio etc).

Any experience/tips/advice would be greatly appreciated.
Thanks

Charles


We have the same blackout problems on our farm and have been looking for a
suitable generator as well. I really wouldn't try to have a generator that
can handle the whole house though. This requires some form of switchover
between the systems which has to be reliable.

Instead we intended to put a number of clearly labelled sockets from the
generator around the house so that they can be used as needed, plus some
dedicated lights. The freezer and heating system (boiler/pump/valves) will
be driven through battery backup UPSes so these will switch automatically
and keep going for a couple of hours. If you want other electronic devices
(TV. computer, etc) I would do the same for these rather than driving them
from a generator which can be spikey.

Charles wrote:
Hi

I live out on a remote farmhouse whose electric is supplied on overhead
electricity
poles.

In the two years that I have lived here, I've had about 20 power cuts.
Some are only a few minutes and a nuisance, but others can last for a
few hours.
snip
I would be happy if the generator would power a lighting circuit, and
maybe a few appliances (heating pump, boiler, television, radio etc).

It depends what you want.

The cheapest option is a small generator that you plug stuff into.
The best option would be a UPS, which can take power from either
the mains, or the generator, and will provide instant recovery from
failure.

A relatively easy way would be a small UPS plugged into a socket on
a ring.

Add another socket for the generator output.

From the UPS output, run a ring, from which are a few low-power (round 2A?)
sockets, and lighting (not exterior security lights).

Plug TV/... into these.

If power-cut happens, then after a few minutes, you unplug the UPS and
pilug it into the generator, then turn it on.
A "proper" solution would use a transfer relay to automate the transfer,
and some means of automatically starting the generator.

On 17 Jan 2005 06:38:06 -0800, Charles wrote:

In the two years that I have lived here, I've had about 20 power
cuts. Some are only a few minutes and a nuisance,

UPS's are great for preventing your computer(s) throwing a wobbly with
the short ones.

I have lots of space outside, and a space ready for a power
generator (petrol/deisel etc).

Take a look on eBay, the biggest up there ATM is 800kVA, comes in an
acoustic container with arctic trailer base. 5 figure price tag though
and fuel might run a bit expensive but you could flog the excess to
the surrounding villages...

- How do I calculate the power (watts) that an appliance requires?

Look at it's rating plate. But be aware that things with motors need 2
or 3 times the rating to start, especially induction motors (fridges,
freezers etc)

- Is there a device that can measure the power requirement for an
appliance,

Maplin and Machine Mart have plugin power meters. The Maplin one
seemed to get good reports recently (in here? try google).

or my entire power requirement (I have an economy 7 dual dial
meter)

How is space heating achieved, electric storage, oil, gas, other? I'd
forget about trying to run storage heaters of a genny as the size of
genny required would be rather large compared to your base load.
Better to find an alternative emergency heat source, wood burner,
portable gas fire or similar.

- When my power is initially connected after a power outage, all of
the outside floodlights come on and create an initial surge. How
would a generator cope with that?

Things with motors probably give a bigger surge unless you have
several kilowatt of external lighting. The easy solution to the to
these surges is to pull the fuses or trip the MCBs them whilst
starting up on genny. Then put the required ones back in one by one
letting the genny recover between switch ons.

I would be happy if the generator would power a lighting circuit,
and maybe a few appliances (heating pump, boiler, television, radio
etc).

Don't forget the freezers/fridges... Assuming that that "lighting
circuit" doesn't include you 10kW of exterior floodlighting then a
smallish 3 to 4kVA generator should cope with all that load fairly
easily.

Do take care of how you connect it into the house. Not only does it
have to be totally fail safe in disconnecting the incoming mains when
you are generator but you also need to think about earthing
requirements. The former to stop you electricuting some poor linesman
fixing the original fault. The latter so that you installation remains
safe but how you achieve that varies on how you normal "mains" earth
is derived.

Google is your friend, there have been many and long discussions in
here on this subject in the past.

--
Cheers
Dave. pam is missing e-mail

- How do I calculate the power (watts) that an appliance requires?

normally theyre marked. With the odd item that isnt, if you dont have
the ability to figure it out, use a power measuring meter such as the
'kilawatt' or similar.

But with gens its the VA that counts, not the W. Motors normally have
both W and VA marked on the ratings plate. VA is larger than W for some
goods, especially motors and fluorescent lights.


- When my power is initially connected after a power outage, all of
the
outside floodlights come on and create an initial surge. How would a
generator cope with that?

how many lights? of what type? What genny rating? What other loads?

The only way gennies can cope with big surges is to drop speed right
down and either pick up again slowly or stall, depending on the nature
of the load.

Best option is to avoid surge loading the thing, there are a number of
ways to do this. But in your case, is the surge a problem for the genny
to begin with?


I am assuming that once I have worked out my power requirement, I will
need to find a generator large enough to cope with it.

Possibly, or you'll swear and decide to drop your load expectations.

Having run on 2 generators before, I'd say that trying to run them at
max ratings is a real mistake. Both must have dropped to less than half
speed under full load, making the nameplate ratings distinctly
optimistic. Yeah sure, it _can_ put out 30A... at about 100v. Really we
never got anything like rated output from either of them. I didnt know
squat about engines at the time though.


I would be happy if the generator would power a lighting circuit, and
maybe a few appliances (heating pump, boiler, television, radio etc).

Beware of putting TVs on gens, they tend to not survive. UPS much
better there - or more realistically, just dont bother.

Gens produce large surges when loads are switched off, and such surges
can kill electronic goods.

Radios can power themselves if fitted with rechargeable batteries plus
a diode/resistor so the batteries charge automatically.


NT