When the speed of the generator is at a predetermined value, the voltage suddenly drops from the rated value to about 85% of the rated voltage. The frequency of this point is called the inflexion of the frequency. The generator with 60Hz and 50Hz will speed the inflection point to 57.5 Hz and 47.5 Hz respectively when the product leaves the factory. The adjustment steps are as follows:
Adjusting the 60 Hz generator crutch, closing K2 (unplugging to "on"), increasing the unit frequency to 60 Hz, the generator voltage reaching the rated value, then slowly reducing the unit rotational speed to 57.5 Hz, then adjusting the potentiometer RP5 to make the terminal voltage drop suddenly, Then RP4 makes the generator terminal voltage drop suddenly and then adjust the RP4 so that the generator terminal voltage is 85UN. the adjusted potentiometer RP5 should not move again.
Adjusting the inflection point of 50 Hz generator, disconnecting K2, slowly reducing the rotating speed of the unit, reducing the frequency to 47.5 Hz, adjusting the generator voltage to the rated value, and then adjusting the RP3 to make the voltage suddenly drop, Then the RP4 is adjusted so that the generator terminal voltage is 85UN. the position of RP3RP4RP5 is well marked, and the position of RP4RP5 does not move again.
When the generator is loaded with rated load (COS φ 0. 8 lag), the generator terminal voltage should be reduced, and the differential potentiometer should be adjusted so that the generator terminal voltage is lower than that of the no-load terminal voltage (3 / 5) / UN (depending on the need). If the generator terminal voltage will rise during the load lifting process, it is necessary to swap the positions of the secondary side of the left current transformer and the two wire terminals.
In parallel operation of two generating sets, the external characteristics of the two units should be adjusted to a basic consistency, that is, when each unit has rated load, the terminal voltage will drop to 3UN.
The generator is established by self-excitation of exciter remanence and has been magnetized when it leaves the factory. However, due to storage, transportation, vibration, and the reason may lose magnetic and can not build pressure, this time need to be remagnetized. Magnetization method: at rated speed or close to rated speed, the 6V DC power supply is connected to the magnetic field winding terminal E / E of the roller machine. Power positive E, power negative E -, lasting 1-2 seconds.
The control panel of the professional Volvo generator set produced by British Deepwater Company has the characteristics of compact structure, beautiful appearance, superior performance, reliable quality and so on.
(1) Manual control screen DSE501K
The DSE501K manual control screen is a manual start / stop control screen. The control screen adopts foreign high quality components, small volume, high reliability, beautiful appearance, strong protection function, overspeed and high water temperature. The oil pressure is too low and has the function of acousto-optic reverse alarm, and has battery voltage and normal operation index.
Panel diagram of DSE501K control cabinet
1. Voltage meter 2. Frequency table 3. Ammeter
4. Voltage conversion switch 5. Timer 6. 501K control 7. Water thermometer
8. Oil pressure gauge
1. Emergency shutdown
2. The oil pressure is too low.
3. The temperature of the water is too high.
5. Charger fault
6. Key switch: stop / operation bit / start bit
(2) description of operations
Startup and shutdown are carried out by operation 501K.
Turn on: when all the starting work is ready, turn the electric key to the operating position, and then to the starting position, then start the motor running about 2-4 seconds, diesel engine operation, release key switch automatically back to the operating position, start successfully. Set the generator set to rated speed through governor or electronic governor.
Stop: turn the key to off position
Switch: by turning the switch, you can choose different phase voltage and line voltage.
Some of diesel generator set installs mechanical governor, others installs electronic governor. Both kinds of governor can guarantee the quality of electric power absolutely, but the generator set equipped with electronic governor is very convenient for automatic protection and automatic control.
All electronic governor of our generator set are adjusted, users do not need to do this work. However, after engine overhaul or failure repair affecting the work of electronic governor, adjustment is needed.
The electronic governor control unit is installed in the control box of the upper part of the generator
A. Dial the switch C1 to the ON position. If there is a fast traffic phenomenon when the engine is running, dial C2 to (OFF) position.
B. Dial the switch C2 to the on position.
C. Transfer the "gain" and "stability" potentiometers to the middle position
D. Temporarily connect terminal L and M together
A. After starting the generator unit , the engine is operated at idle speed ( about 400 rpm ) , and the idle speed can be increased by rotating the idle ( IDLE ) potentiometer clockwise . The potentiometer is of a single turn type . Therefore , the adjustment should be carefully performed , and the potentiometer should not be rotated to the maximum position .
Warning! Running at very low speed for a long time will damage elastic coupling joints, engines, generators!
B. After knowing that the engine is working normally, the engine speed rises to about 1567 revolutions / min by removing the connection of the Lom terminal.
C. Final adjustment
Engine idling, clockwise rotation gain (gan) potentiometer until the engine began to unstable. Then back the potentiometer to the engine to work stable, and then back 1 / 8 laps.
Adjust stability in the same way as above
Note: when the gain potentiometer is adjusted, the preset engine speed may change, so the speed (speed) potentiometer should be used again to adjust the engine speed to 1567 rpm / min (reading 52.2 Hz on the frequency meter).
After the above speed regulation is completed, the work can be added to the load. In general, these adjustments have a critical point when the cooler is empty, so it may need to be adjusted again.
The clockwise rotation of gain (gan) potentiometer will increase the speed of the governor's response to the load change, while the counterclockwise direction will decrease the speed of the governor's response.
Clockwise rotation stability (STABILITY) potentiometers shorten the recovery time of the governor system after load changes, and increase the recovery time in counterclockwise direction.