METHOD OF SELECTING AN ALTERNATING CURRENT (A.C.) GENERATING SET

In selecting an Alternating Current (A.C.) generating set consider the following points:

1. Total electrical load connected – including any motors i.e. Bore hole pump etc.
2. Voltage, frequency and phase
3. Special requirements
4. Whether automatically started or not
5. Acceptable sound emissions

Connected Load or Assessed Load

Having assessed the total connected load, consider next the portion of the load that is likely to be switched on at any time. A Generator set with an output a little in excess of the figure should be selected to allow for contingencies. Always allow for future expansion.

Typical Voltage in Domestic and Commercial Applications

1. Residential

       a. Housing - 230 Volts - Single Phase
       b. Housing - 400 Volts - Three Phase

2. Commercial

       a. Offices / Manufacturing - 400 Volts - Three Phase

Types of Starting Systems and Controls

Recoil Start: With a recoil starter rope.

Electric start: This is frequently available as standard equipment and on most large sets.

Remote Starting / Stopping: To permit the Generator set to be started and stopped from the house or other remote position with a remote button. See Remote Start Button.

Manual change over: This is a manual switch normally with a pilot light wired so that when the mains is on the light shows. It would have a Mains/Neutral/Generator switch to ensure that it is either mains on or generator on but never both. See Manual Change Over Switch.

Automatic Standby to Mains: Sets can normally be supplied which start automatically and take up the load when the mains fail. On restoration of the mains supply the load is automatically transferred to mains and the generator set shuts down. There will always be a delay between mains failure and the generator starting up and supplying full load so if sensitive equipment is being used or computer systems an Uninterrupted Power Supply (UPS) should be installed to ensure no loss of Data. Time delay on switch over can be between 30 seconds and 60 seconds dependent on the generator system installed. See Automatic Change Over Switch.

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