SOP Engineering - Different Modes For Starting Diesel Generator
SOP Number: Hotel Engineering SOP – 30
Department: Engineering and Maintenance
Date Issued: 10-Jan-2019
Time to Train: 15 Minutes
Different Modes For Starting Diesel Generator (DG) Set
The following procedures are adopted for starting diesel generator set using a battery:
1. Push-button (Manual)
2. Autostart (Auto)
3. Test mode (For the testing purpose)
Note: The mode of operation can be selected by means of the selector switch.
1. Push Button Start/ Manual Mode:
After pressing the start push button and turning the ignition key toward start position, the battery is connected to the starter which cranks the engine shaft resulting in the start of the engine.
This arrangement can also be provided in small DG sets.
This requires the least physical efforts to start a DG set.
To prevent damage to the starter, do not push the start button for more than 10 to 12 seconds.
2. Auto Starting System/ Auto mode:
This method is adopted where the supply from the generator is regularly required.
In this mode, the DG set starts automatically in case of (i) mains failure, (ii) low/high mains voltage beyond 150-250 V for single-phase DG set and 360-460 V for 3 phase.
DG set (iii) single phasing or phase reversal of the main supply.
When the engine starts and alternator reaches the preset voltage, the DG contactor closes and automatically restores the supply to the load.
The auto-start system makes three attempts to start, in case it fails to start, the starting system automatically disconnected and locked out.
After the restoration of healthy mains voltage, the DG contactor opens and the main supply extended to the load.
However, the DG set continuous to run for 3 minutes and shut down after that if mains supply remains stable.
During the above mentioned 3 minutes, if the mains fail again, the DG shutdown sequence discarded and the DG contactor closes again to restore the DG supply to the load.
3. Test mode
- In this mode, all functions are likely to manual mode but DG supply can not be transferred to load. This mode is provided for the purpose of testing the DG set.