Hi

I am not much of mechanic/electrician so please excuse me if I sound a total simpleton , but wonder if anyone can advise regarding suitable generators and output required for running a small three bedroomed house during powercuts. Have seen these superquiet Honda EU3000is models, but unsure if they would be sufficient for running multiple individual items (fridge/freezer/TV/computer and a couple of lamps all at once). To run a house via a generator I assume that a convertor switch is required and therefore dies anyone know how problematic it is in getting a stitch box connected (i.e) to transfer from mains to generator supplied electricity connected and then what size generator would be required to run the house with the majority of essentials?

Any comments appreciated as long as they are too complex for as I have said I am not a mechaanic/electircian geek.


Mr Eq

Evening Mr Eq

OK found this on Google so lets start at the beginning first worth reading.

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Oddy

Many thanks Berni (Oddy)

Did say I am not a mechanical/electrical geek.

Must say Google really help especially when trying to find stuff but tend to get a bit bogged down occasionally.

As Mrs Eq says, realistically the main thing would only be worrying about making sure the freezers keeps going to avoid food that we have produced spoiling.

Thanks for the advice

Mr Eq

I found that for occasional use during power cuts that my 3kva is sufficient to run the kettle,pump for heating,TV and lights which is all you really need for occasional use.

If the price isn't much different then go a little higher it always better to have more than you need. As ABC has said 3kva will do you fine .

Thanks both. If we didn't use it for lighting etc, would it keep a freezer going? We can manage with other forms of lighting, and hopefully will have a log burner without it being attached to heating somewhere in the house. But if we have a lot of food in the freezer it wouldn't be good if we lost it. On the other hand, presumably it would only be certain areas who have long power cuts. Just trying to think of all pitfalls really. Mr Eq says I am a pessimist and should lighten up.......takes one to know one I say!!!

Spooky thing happened last night. Bearing in mind we have had possibly only one power cut since moving here 7 years ago, as Mr Eq was settling to reading the website Oddy had pointed out....the leccy went off! How weird is that? Stayed off for an hour, unheard of!

Just one other thing and that is if you can take one from the uk with you because most of what you get in Bg isn't really upto much in my opinion.

To be honest when I lived in Bulgaria we only had power cuts in the winter and these were very short lived so I didn't bother with a generator at all but I do see why some people do have a standby

Please use common sense and be aware of the danger of electrocution at all times. If you are in any doubt, seek the advice of a qualified electrician.

The following steps are a guideline to assist you in establishing the optimum size generator for your use.

To correctly size a generator for home or business use, you will need to determine your power requirements by calculating the load (‘load’ is the current required to run your appliances) of your home or business. This can be achieved in one of three ways.

The first and easiest way to measure the load is to use a ‘tong tester’ with a digital readout. A tong tester is a tool used to measure ac/dc current in amps. The jaws of the tong tester are normally spring loaded and can be placed around the live cable of the mains supply (between the meter and distribution board). With the tong tester in place, you should now turn on every appliance you wish to power with the generator. If you only require certain circuits to be powered by the generator, isolate them by turning off the circuits you will not require at the distribution board. Once all appliances are turned on and your home or business is at full load, the tong tester will display the current drawn (in amps). Make a note of the amperage reading displayed on the tong tester.

Generators are sized in kilowatts, so you will now need to convert your amperage reading into kilowatts using the following formula;
Volts x Amps x Power Factor = Watts.

In Thailand the domestic single phase supply is 220v ac. Power factor involves the efficiency in the use of the electricity supplied to the system. For most generators calculations we use a power factor of 0.80, for example;
if your amperage reading was 80amps on full load, the calculation would read as follows:

Volts (220v ac) x Amps (80amps) x Power Factor (0.80) = Watts (14,080)

Given this example, the load requirement for your home or business is 14 kilowatts.

Diesel powered generators operate most efficiently when they are running at 70 to 80% of their maximum rated power output, this also allows for future growth in power demand. A 14Kw load is approx 80% of the maximum load rating of a 17Kw (21Kva) generator which is therefore the optimum size generator to power your home or business (to calculate Kva from Kw, the formula is;
Kw / 0.80 = the value in Kva).

The second method, if your home or business is supplied with a traditional style kilowatt hour meter with a rotating disc, is to calculate the amps used by using a stopwatch as the disc rotates.

If you have a meter with a rotating disc, first read the constant value on the face of the nameplate (shown as Kh). This value is the number of watt-hours equivalent to one rotation of the disk.
Now, start the desired appliances, heating or air conditioning as in the previous example with the tong tester.
Using a stopwatch while watching for the black mark on the meter's disk, measure the time it takes for one or more disk rotations. If the disk is rotating rapidly, better accuracy will be attained if you time more than one rotation.
Finally, take the three values and use the equation below to calculate the watts seen by the electric meter.

  Kh = meter constant
  Rev = revolutions of disk used
  T = total time from stopwatch for revolutions of disc

  Watts = Kh x Rev x 3600
  T

Here is an example calculation for a meter with a reading of Kh = 7.2 per disc revolution. The time measured for 5 rotations of the disk was 24 seconds. Thus, Rev = 5 and T = 24 seconds. Solving for the electrical demand we have:

   Watts = Kh x Rev x 3600  T

  = ( 7.2 watt-hrs/rev ) x ( 5 rev ) x ( 3600 sec/hr)
  24 seconds

  = 5400 watts.


The third and final method is a simple calculation of the power requirement for each and every appliance to be placed on load as follows:
 
· Identify the appliances the generator will power. - If the generator is to power all appliances in your home or business, make a list of every appliance. If only certain circuits are required, make a list of every appliance on those circuits.

· Determine the wattage for each appliance. – Determine the wattage for each resistive load on your list (toasters, coffee makers, light bulbs, convection ovens, televisions etc are examples of resistive loads). Typically, resistive loads do not contain an electric motor.

Generator Power Calculator

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Very useful nets thank you.

cheekychops wrote:

Very useful nets thank you.

Likewise many thanks nets

Mr Eq