What size Generator do I need?
The ideal generator size is one that is correctly matched to power all the things you want to run at the same time.
If it is too big, not only will it be more expensive to purchase, but it will not necessarily run as efficiently as the correctly matched size.
If it is too small, some of your equipment may not give it maximum output, and at times its lifespan may be reduced.
Here's all you do-
All electrical appliances and motors, should have (by law), an electrical rating plate with the power and electrical requirements shown on it.
- If the appliance has a rating plate showing:
Watts - If this is shown as kW multiply x 1000 which = Watts
HP - To return this old measure to Watts multiply x 746 = Watts
- If there is no rating plate showing the power, please refer to the 'Average Watts Table' below, showing typical appliances that you can compare to yours and select and ‘Average Watts’ figure.
For standard Industrial Electric Motors, the power shown on the motor rating plate does not take into account the motor efficiency or starting load, and therefore – Look up the chart below for Electric Motors and use the ‘Average Watts’ figure shown for the particular standard size motor indicated.
Now all you have to do is Add up!
Just add up all the ‘Average Watts’ for every appliance or motor that you are going to run at any one time, and choose the biggest combination of loads.
Just pick a Generating Set Watt equal or which has a slightly greater than your total ‘AverageWatts’.
If you are not very technically minded, and do not have confidence in your choice, either from our Master Chart, or from these calculators, do not hesitate to ring us and we will be happy to work it our for you.
A typical example - If under the heaviest work circumstances we are going to run the following electrical devices at the one time, what Generating Set do I need?
| 5 | x | 100 Watt Lights | = | 500 Watts |
| 1 | x | Kettle | = | 1,800 Watts |
| 1 | x | Toaster | = | 600 Watts |
| 1 | x | 550 Watt Motor requires 2,200 'Average Watts' from table | = | 2,200 Watts |
| TOTAL AVERAGE WATTS | = | 5,100 Watts | ||
Therefore, for example a PB060 (Briggs & Stratton, Vanguard Engine) or PH060 (Honda Engine), which has a ‘Real Power’ capacity of 5,600 Watts would be ideal, and it even has an additional 8% extra capacity.
Please note: a generator should never be operated at its maximum wattage capacity for more than 30 minutes. If you need to operate a generator for more than 30 minutes, it is recommended you use only 90% of the maximum wattage. Generators at all times need to be in a well ventilated area and powerpoints should never be overloaded.
Other Options to consider …
Is Electric or Manual Recoil Start Needed?
These days recoil start generators are easy to start. It depends on what you would prefer.
Manual Recoil Start Generators are hand operated, whereby you start the generator with a pulling motion on a cord.
Electric Start Generators are key started with a battery attached. Electric start generators are ideal for people who just don’t have the strength or power to start a recoil start generator.
Petrol or Diesel?
It really depends on where you use the generator or how often you use it. Petrol generators are primarily designed for not running for extended periods of time at maximum load. In addition, petrol generators, because of their simpler design, are less expensive that diesel engines.
Diesel generators are primary designed to operate near or at full power for extended periods of time.
Just a Word of Caution
The above explanations and calculations have been simplified and generally cover most commonly encountered domestic and light trade requirements. Because of the varying nature of many electric motor driven devices, we would recommend that you contact us where you feel that your circumstances may be different.
