Stamford AVR SX460,sx460 avr for stamford

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. 

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 +/- 1.5%.

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.

Technical Specifications

Input

Voltage:Jumper selectable  95-132V ac or 190-264V ac

Frequency :50-60 Hz nominal

Phase : 1

Output

Voltage:max 90V dc at 207V ac input

Current :continuous 4 A dc  Intermittent 6 A for 10 secs

Resistance:15 ohms minimum

Regulation

+/- 1.5% (see note 1)

Thermal Drift

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

Environmental

Vibration: 20-100 Hz   50mm/s  100Hz – 2kHz      3.3g

Operating temperature:  -40 to +70°C

Relative Humidity 0-70°C: 95% (see note 5)

Storage temperature: -55 to +80°C

Notes

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.