WEG AVR-A-OPT-03 Installation, Operation And Maintenance Manual page 17

This operation mode is determined by trimpot U/F, jumper JHz and associated components. The jumper JHz determines
the operation frequency, that follows the logic bellow:
JHz position 1-2 = 50Hz
JHz position 2-3 = 60Hz
The trimpot U/F determines the actuation point in U/F mode that can be from the rated frequency (Fn) to 1/3 of Fn, which
value comes adjusted by the factory in 10% below Fn. For operation in 60Hz it's adjusted for 54Hz and for operation in
50Hz it's adjusted for 45Hz (see Figure 12.2), this value can be changed according to the needs of each application.
U/F (50Hz)
U/f
* Us = Output voltage
ATTENTION
1. Don't let the U/F protection opened. The configuration must be done according Figure 12.2 to avoid
problems when shutting down. The frequency limited by U/F is the frequency of the waveform that
is at the power supply input of the regulator and not at the sensing input.
12.2 CURRENT LIMITER
The current limiter circuit makes the analysis of the field current and compares with a pre-fitted maximum value. When the
current exceeds the maximum value, the limiter reduces the detonation of the thyristor, keeping the power supplied to the
field of the constant generator. While the current is minor than the maximum, the regulator operates normally and the
current limiter remains incapacitated. This protection is present only in AVR-A-OPT-03/C version.
13 FIRTS USE
STEPS FOR THE REGULATOR CONNECTION:
1. Connect the wires coming from the alternatoraccording to the description on items 18 and 21 and the type of alternatorto
be used (item 14, 15, and 16).
2. Before the alternatoris turned on the primary mover should be started and run at rated speed.
3. The alternatorshould start without load. The potentiometer for Voltage adjustment should be configured to the minimum
voltage to avoid alternatorrunaway in case incorrect connections.
4. The potentiometer for stability should be placed in the middle of its course. This potentiometer acts on the dynamic
response of the machine and does not affect the normal permanent operation.
Un
F (Hz)
45 50
Figure 12.2: Operation of the protection U/F
U/F (60Hz)
U/f
Analog Voltage Regulator AVR-A-OPT-03
www.weg.net
Un
F (Hz)
54 60
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