SX460 General description
SX460 is a half-wave phase-controlled thyristor type Automatic Voltage Regulator (AVR) and forms part of the excitation system for a brush-less generator. In addition to regulating the generator voltage, the AVR circuitry includes under-speed and sensing loss protection features. Excitation power is derived directly from the generator terminals.
Positive voltage build up from residual levels is ensured by the use of efficient semiconductors in the power circuitry of the AVR.
The AVR is linked with the main stator windings and the exciter field windings to provide closed loop control of the output voltage with load regulation of +/-1.0%.
In addition to being powered from the main stator, the AVR also derives a sample voltage from the output windings for voltage control purposes. In response to this sample voltage, the AVR controls the power fed to the exciter field, and hence the main field, to maintain the machine output voltage within the specified limits, compensating for load, speed, temperature and power factor of the generator.
A frequency measuring circuit continually monitors the generator output and provides output under-speed protection of the excitation system, by reducing the output voltage proportionally with speed below a pre-settable threshold. A manual adjustment is provided for factory setting of the under frequency roll off point, (UFRO). This can easily be changed to 50 or 60 Hz in the field by push-on link selection.
Provision is made for the connection of a remote voltage trimmer, allowing the user fine control of the generator's output.
Voltage: Jumper selectable 95-132V ac or 190-264V ac
Frequency: 50-60 Hz nominal
Voltage: Max 90V dc at 207V ac input
Current: Continuous 4 A dc
Intermittent 6 A for 10 secs
Resistance: 15 ohms minimum
+/-1.0% (see note 1)
0.05% per deg. C change in AVR ambient (note 2)
TYPICAL SYSTEM RESPONSE
AVR response: 20 ms
Filed current to 90%: 80 ms
Machine Volts to 97%: 300 ms
EXTERNAL VOLTAGE ADJUSTMENT
+/-10% with 1 k ohm 1 watt trimmer (see note 3)
UNDER FREQUENCY PROTECTION
Set point: 95% Hz (see note 4)
Slope: 170% down to 30 Hz
UNIT POWER DISSIPATION
10 watts maximum
BUILD UP VOLTAGE
4 Volts @ AVR terminals
Vibration: 20-100 Hz 50mm/sec
100Hz -2kHz 3.3g
Operating temperature: -40 to +70
Relative Humidity: 0-70 95% (see note 5)
Storage temperature: -55 to +80
1. With 4% engine governing
2. After 10 minutes.
3. Applies to Mod status F onwards. Generator de-rate may apply. Check with factory.
4. Factory set, semi-sealed, jumper selectable
5. Non condensing.