Stamford SX460 AVR
Stamford SX460 AVR

Stamford SX460 AVR

Regular price £189.00 (Ex. VAT) Sale

SX460 AUTOMATIC VOLTAGE REGULATOR (AVR) SPECIFICATION, INSTALLATION AND ADJUSTMENTS GENERAL DESCRIPTION
The SX460 is a half-wave phase-controlled thyristor type
Automatic Voltage Regulator (AVR) and forms part of the
excitation system for a brushless generator.
In addition to regulating the generator voltage, the AVR circuitry
includes under-speed and sensing loss protection to ensure
safe, reliable control of the generator. 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 +/- 1.5%.
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 underspeed protection
of the excitation system, by reducing the output voltage
proportionally with speed below a presettable 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 wire link selection.
Provision is made for the connection of a remote voltage
trimmer, allowing the user fine control of the generator's output.
TECHNICAL SPECIFICATION
INPUT
Voltage 85-125 V ac ü
ý Jumper Selectable
170-250 V ac þ
Frequency 50-60 Hz nominal
Phase 1
OUTPUT
Voltage max 90 V dc at 207 V ac input
Current Continuous 4 A dc
Transient 6 A for 10 seconds
Field Resistance 15 Ω minimum
REGULATION (See Note 1) +/- 1.5%
THERMAL DRIFT
(after 10 min)
1% for 40°C change in AVR ambient
TYPICAL SYSTEM RESPONSE
Field current to 90% 80ms
Machine Volts to 97% 300ms
EXTERNAL VOLTAGE ADJUSTMENT
+/- 5% with 1 K Ω trimmer
UNDER FREQUENCY PROTECTION
Set Point (See Note 2) 95% Hz
Slope 170% down to 30 Hz
UNIT POWER DISSIPATION
10 watts maximum
BUILD UP VOLTAGE
3.5 V ac @ AVR terminals
ENVIRONMENTAL
Vibration 20-100 Hz 50mm/sec
100 Hz-2 kHz 3.3g
Relative Humidity 0-60°C 95%
Operating Temperature -40°C to + 70°C
Storage Temperature -55°C + 80°C
NOTES
1. With 4% engine governing.
2. Factory set, semi-sealed, jumper selectable.