Basic Info.

Model NO.:MX321, E000-23212

Trademark:STAMFORD

Production Capacity:100PCS/YEAR

MX321 GENERAL DESCRIPTION
The MX321 is a three phase, 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 protective features to ensure safe reliable control of the generator. Excitation power is derived from a permanent magnet generator (PMG) to guarantee low Radio Frequency Interference (RFI) and immunity from thyristor type loads.

The AVR is linked with the main stator windings and controls the power fed to the exciter stator and hence the main rotor to maintain the machine output voltage within the specified limits, compensating for load, speed, temperature and power factor of the generator.

Soft start circuitry is included to provide a smooth controlled build up of generator output voltage.

Sustained overvoltage caused by open circuit sensing terminals is avoided by overvoltage detection circuitry which provides internal shutdown of the AVR output device.

Current limiting may be included to allow control over the amount of short circuit current flowing during three phase and single phase short circuits on the generator output.

Uncontrolled over excitation is limited to a safe period by internal shutdown of the AVR output device. This condition remains latched until the generator has been stopped.

For complete protection, a circuit breaker option is available providing circuit isolation in event of a short circuit power device.

Provision is made for the connection of a remote voltage trimmer allowing the user fine control of the generator's output.

Accessories are available for this AVR. Please refer to factory for further details.

*The stated voltage regulation may not be maintained in the presence of certain transmitted radio signals. Any change in regulation will fall within the limits in Criteria B of EN50082-2.

TECHNICAL SPECIFICATION

SENSING INPUT
Voltage: 170-250 V AC max
Frequency: 50-60 Hz nominal
Phase: 1 or 3
Wire: 2 or 3

POWER INPUT (PMG)
Voltage: 170-220 V AC
Current: 3 A/phase
Frequency: 100-120 Hz nominal
Phase: 3
Wire: 3

OUTPUT
Voltage: Max 120 V DC
Current: Continuous 3.7 A (See note 3)
Transient: 6 A for 10 seconds
Field Resistance: 15 Ohms minimum

REGULATION(See Note 1) +/- 0.5% RMS*

THERMAL DRIFT
(after 10 min)
0.5% for 40º C change in AVR ambient
SOFT START RAMP TIME
0.4 - 4 seconds

TYPICAL SYSTEM RESPONSE
Field current to 90% 80ms
Machine Volts to 97% 300ms

EXTERNAL VOLTAGE ADJUSTMENT
+/- 6% with 4.7 K Ohms trimmer

UNDER FREQUENCY PROTECTION
Set Point (see note 2) 95% Hz
Slope 100-300% down to 30 Hz
Dwell (Recovery) 0.5-2.0 seconds

UNIT POWER DISSIPATION
18 watts maximum
A

CCESSORY INPUT
+/- 1 V = +/- 5% change in output volts

QUADRATURE DROOP
Maximum sensitivity (10 Ohms Burden)
0.22 A for 5% droop @ 0p. F.

CURRENT LIMIT
Sensitivity range (10 Ohms Burden) 0.45 A - 1 A

OVER VOLTAGE PROTECTION
Set Point 300 V
Time Delay (fixed) 1 second
Circuit breaker trip coil voltage 40-60 vdc
Circuit breaker trip coil resistance 50-100 Ohms

OVER EXCITATION PROTECTION
Set Point 75 V DC
Time Delay (fixed) 8-15 seconds

ENVIRONMENTAL
Vibration: 20 - 100 Hz 50mm/sec
100 - 2 kHz 3.3G
Relative Humidity: 0- 60º C 95%
Operating Temperature: -40 to +70º C
Storage Temperature: -55 to +80º C

Additional Info.

Product Description