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| Illustration 1 | g02320335 |
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(1) Rotating switch (Excitation type and time response)
(2) Rotating switch (Voltage sensing) (3) Rotating switch (LAM and U/F) (4) "P1" Voltage (5) "P2" Stability (6) "P3" Excitation (7) Excitation limiting/overload indicator LEDs (8) 10 Amp fuses (9) Field and excitation supply connections (10) Model designation (11) "P4" (Quad droop) (12) Droop current transformer input (13) Remote voltage adjustment potentiometer input | |
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The high voltage that is produced by an operating generator set can cause severe injury or death. Before performing any maintenance or repairs, ensure that the generator will not start. Place the engine control switch in the "OFF" position. Attach "DO NOT OPERATE" tags to all starting controls. Disconnect the batteries or disable the starting system. Lock out all switchgear and automatic transfer switches that are associated with the generator. |
The R450 AVR may control any of the following excitation systems: AREP, PMG and SHUNT.
Excitation Type and Time Response Rotating Switch
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| Illustration 2 | g02352788 |
0 - "AREP" excitation and normal time response
1 - "PMG" excitation and normal time response
2 - "PMG" excitation and fast time response. For "SHUNT" applications, "AREP" excitation must be selected.
3 - "AREP" excitation and fast time response.
Voltage Sensing Rotating Switch
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| Illustration 3 | g02352789 |
0 - Voltage from 320V to 530V (5000/6000 series)
1 - Voltage from 80V to 320V (5000/6000 series)
2 - Voltage from 80V to 320V (7000/8000 series)
3 - Voltage from 320V to 530V (7000/8000 series)
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| Illustration 4 | g02352790 |
0 - Change in the voltage according to the U/F ratio. Knee point position at 48 Hz.
1 - Change in the voltage according to the 2 U/F. Knee point position at 48 Hz.
2 - Change in the voltage according to the self auto-adaptive LAM combined with 2 U/F. Knee point position at 48 Hz.
3 - Change in the voltage according to the U/F ratio. Knee point position at 58 Hz.
4 - Change in the voltage according to the 2 U/F. Knee point position at 58 Hz.
5 - Change in the voltage according to Change in the voltage according to the self auto-adaptive LAM combined with 2 U/F. Knee point position at 58 Hz.
6 - Change in the voltage according to the U/F ratio. Knee point position at 65 Hz.
7 - Special (not used)
8 - Change in the voltage according to the U/F ratio. Knee point position at 48 Hz or 58 Hz according to the selection of the frequency by an external contact.
9 - Change in the voltage according to LAM 1. Knee point position at 48 Hz or 58 Hz according to the selection of the frequency by an external contact.
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| Illustration 5 | g03394038 |
With "SHUNT" excitation, the AVR is powered by the main winding (100V to 140V) by using "X1, X2" on the AVR. The rotating switch should be in the "SHUNT/AREP" position.
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| Illustration 6 | g03394039 |
The electronic AVR is powered by two auxiliary windings which are independent of the voltage sensing circuit.
The first winding has a voltage proportional to the alternator main voltage ("SHUNT" characteristic). The second winding has a voltage proportional to the stator current (compound characteristic: Booster effect).
The power supply voltage is rectified and filtered before being used by the AVR monitoring transistor. The excitation principle provides the generator set with a short circuit current overload capacity of 3 IN for 10s. The rotating switch should be in the "SHUNT/AREP" position.
A qualified engineer must make adjustments during tests of the AVR. The drive speed specified on the nameplate must be reached before starting the adjustment. After operational testing is completed, replace all access panels and covers.
The AVR adjusts the equipment.
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Before using the AVR, correctly configure the rotating switches with AREP/SHUNT or PMG excitation. |
Initial Potentiometer Settings
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"P1" - Voltage minimum fully anti-clockwise (Factory setting 400V - 50 Hz) |
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"P2" - Stability (Not set) |
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"P3" - Excitation ceiling (Factory-sealed) 10 Amp maximum |
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"P4" - Voltage quadrature droop (Operation with current transformer) 0 quadrature droop fully anti-clockwise (Not set (fully anti-clockwise)) |
Stability Adjustments (Stand Alone Operation)
- Install a DC analogue voltmeter (needle dial) calibrated 100 V on terminals "F+", "F-" and an AC voltmeter calibrated 300 to 500 V or 1000 V on the alternator output terminals.
- Check the rotating switch selection.
- Voltage potentiometer "P1" at minimum, fully anti-clockwise.
- Stability potentiometer "P2" around 120° from the anti-clockwise stop.
- Start the engine. Set the speed to a frequency of 48 Hz for 50 Hz or 58 Hz for 60 Hz.
- Set the output voltage to the desired value using "P1".
- Rated voltage for solo operation (such as 400 V)
- Or rated voltage (such as 410 V−)
- If the voltage oscillates, use "P2" to make adjustments. Adjustments may be made in both directions. Observe the voltage between "F+" and "F−", which is approximately 10 VDC. The best response time is obtained at the limit of the instability. If no stable position can be obtained. select the fast position.
- Check the LAM operation depending on the rotating switch selection.
- Vary the frequency below 48Hz or 58 Hz according to the operating frequency. Check the change in voltage from the voltage observed previously.
- Readjust the speed of the generator set to the rated no-load value.
Stability Adjustments (Parallel Operation)
Note: Make sure that the speed droop is identical for all engines before working with the alternator.
- Preset for parallel operation with the current transformer connected to "S1", "S2".
Note: Potentiometer "P4" (quadrature droop) in 1/4 position in the case of 5A CT and at 1/2 position in the case of 1A CT.
Apply the rated load (PF = 0.8 inductive). The voltage should drop by 2% to 3% (400V). If the voltage increases, check to make sure that one of the following have been reversed: "V", "W", "S1" and "S2"
- The no-load voltages should be identical for all the alternators which run in parallel.
- Couple the machines in parallel.
- Attempt to obtain 0 kW power exchange by adjusting the speed.
- Attempt to cancel or minimize the current circulating between the generator sets by alternating the voltage setting "P1" on one of the generator sets.
- Do not adjust the voltage settings after the above procedure is completed.
- Apply the available load by one of the following methods. The setting is only correct if a reactive load is available.
- Alter the speed. Match the kW or divide the rated power of the units proportionally.
- Alter the quadrature droop potentiometer "P4". Match or divide the currents.
In the standard setting, the potentiometer "P3" is in maximum position. For applications requiring an overload protection, use the following procedure to adjust the excitation ceiling in AREP and PMG.
- Connect the AVR to the alternator.
- Apply the load to 110% of rated generator set rated at power factor =0.8. The greed lamp is illuminated and the red lamp is off.
- Adjust "P3" until the red lamp is flashing and the green lamp is illuminated.
- Decrease the load to 100% and make sure that the red lamp is not illuminated.
- Increase the load to 115%. Make sure that the red lamp flashes for 90 seconds. Make sure that the excitation current is brought back to the above adjusted value (l ex adjusted)
Multiply the rated excitation current by 1.1. Use the obtained value to set the potentiometer P3. Use the following table.
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| Illustration 7 | g02355098 |
In the case of a permanent short-circuit, the excitation current must reach 2.9 × hex adjusted (clamped to 9.5 A) during 1 second in AREP or 10 seconds in PMG. The current must shut down to a value less than 1 Amp.
Note: When the excitation current is set to the rated value, a voltage dip is observed in the excitation current limit when the limitation is activated and the current limit is reached.
For information about electrical faults, refer to the Systems Operation/Testing and Adjusting, "Troubleshooting" information for the generator set.