7Electrical requirements#
7.1General#
The generator shall operate within the following performance parameters at 40°C ambient temperature, relative humidity of 90% at 500 m MSL (Mean Sea Level).
| Parameter | Rating |
|---|---|
| Type of generator | Prime rated |
| Loading | 100% step loading with speed droop of 5% |
| Earth pin of socket outlet / extension leads | 1 5A |
| No of phases | 1 |
| Voltage | 240 V |
| Voltage regulation | +/- 5% |
| Frequency | 50 Hz |
| Frequency regulation | +/- 2% |
| Power factor | 0.8 lagging |
| Deviation dactor for voltage waveform | 5% |
| Harmonic distortion | 7 % |
| Over loading | 10% for one hour during every 12 hour period |
| Noise level | 65 dBA @ 7 m |
7.2Short circuit performance#
The generator shall provide sufficient current to automatically disconnect a protective device within 0.4 seconds to protect against short circuit currents when the Fault Loop Impedance is within values which are in accordance with the principles Table 8.1 of AS 3000.
The protective device shall comply with the requirements of Clause 2.4.3 of AS/NZS 3000:2007 and can be installed in any of the following methods:
- a)integral to the generator
- b)integral to the load’s supply inlet (e.g. traffic signal controller or main switchboard), or
- c)independent over-current protection unit, or protective junction box, which connects the generator to the load.
The generator supplier shall provide datasheet containing information on the protective device used, the p.u. impedance and full load current and Prospective Short Circuit Current (PSSC) of the generator, or shall do so by measurement, to enable calculation of and Fault Loop impedance prior to installation. Hold Point 1
7.2.1Overcurrent protection unit (terminal box)#
Where a protective device integral to the generator, or integral to the MSB of the load is not available, and independent overcurrent protection unit, or terminal box, connecting the generator to a changeover device installed at the MSB of the load, shall be provided. The unit shall disconnect supply to the load within 400 ms in the event of a short circuit fault. In addition, the unit shall:
- connect to the MSB changeover device in accordance with the principles outlined in Clause 2.5.4 of AS 3010:2005
- have a 15A inlet plug to AS/NZS 3112:2011 to connect to the generator
- have a 15A switched outlet socket to AS/NZS 3112:2011 with a flexible cord integral to the unit. The active wire in the cord shall be overcurrent protected and the neutral is not switched. Earthing and bonding requirements shall be in accordance with Clause 2.5.6 of AS 3010:2005
- provide means for resetting the unit once the overcurrent device has operated
- provide indicators showing the status of the unit
- if using overcurrent relays, provide means for setting the time/current thresholds and hysteresis
- be rated to IP56 or better in accordance with AS 60529
- be suitable to accommodate lugged or clamped termination of the active and neutral XLPE/PVC, non-armoured, 2-core, stranded copper conductor cables of appropriate CSA that comply with AS/NZS 5000.1 and AS/NZS 2276.1
- be of class II (double-insulated) construction in accordance with AS/NZS 3100:2009.
7.3Earthing and bonding#
The prime mover, base plate, generator housing and all other conductive parts shall be electrically bonded to form generator bonding system (see Clause 2.5.6.1 of AS/NZS 3010:2005). A separate terminal connected to the generator bonding system shall be provided in the output terminal box in order to facilitate connection to the earth bar of MEN switchboard.
The neutral shall not be earthed when the generator is connected to a MEN switchboard—refer Clause 2.5.6.2.2 of AS/NZS 3010. Consequently, generators with RCD protection shall not be used when the generator is connected to an MEN switchboard.