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Product Description
Product Description
MX341-A AVR is a two phase sensed Automatic Voltage Regulator and forms part of the excitation system for a brush-less generator. Excitation power is derived from a three-phase permanent magnet generator (PMG), to isolate the AVR control circuits from the effects of nonlinear loads and to reduce radio frequency interference on the generator terminals. Sustained generator short circuit current is another feature of the PMG system.
Voltage Regulator MX341-A senses the voltage in the main generator winding and controls the power fed to the exciter stator and hence the main rotor to maintain the generator 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.
A frequency measuring circuit continually monitors the shaft speed of the generator and provides under-speed protection of the excitation system by reducing the generator output voltage proportionally with speed below a pre-settable threshold. A further enhancement of this feature is an adjustable volts per Hertz slope to improve engine recovery time on turbo charged engines. Soft start circuitry is included to provide a smooth controlled build up of generator output voltage.
Uncontrolled excitation is limited to a safe period by internal shutdown of the AVR output device. This condition remains latched until the generator has stopped.
Provision is made for the connection of a remote voltage trimmer, allowing the user fine control of the generator's output.
An analogue input is provided allowing connection to a Newage Power Factor controller or other external devices with compatible output.
MX341-A AVR has the facility for droop CT connection, to allow parallel running with other similarly equipped generators.
Technical specification
SENSING INPUT
Voltage 190-264V ac max, 1 phase, 2 wire
Frequency 50-60 Hz nominal
POWER INPUT (PMG)
Voltage 140-220V ac max, 3 phase, 3 wire
Current 3A/phase
Frequency 100-120 Hz nominal
OUTPUT
Voltage max 120V dc
Current continuous 2.7 A
Intermittent 6A for 10 secs.
Resistance 15 ohms minimum
REGULATION
+/- 1% (see note 1)
THERMAL DRIFT
0.03% per oC change in AVR ambient (note 2)
SOFT START RAMP TIME
3 seconds
TYPICAL SYSTEM RESPONSE
AVR Response 10 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
12 watts maximum
ANALOGUE INPUT
Maximum input +/- 5V dc (see note 5)
Sensitivity 1v for 5% Generator Volts (adjustable)
Input resistance 1k ohm
QUADRATURE DROOP INPUT
10 ohms burden
Max. sensitivity: 0.07 A for 5% droop 0PF
Max. input: 0.33 A
OVER EXCITATION PROTECTION
Set point 75 V dc
Time delay 10 seconds (fixed)
ENVIRONMENTAL
Vibration 20-100 Hz 50mm/sec
100Hz – 2kHz 3.3g
Operating temperature -40 to +70oC
Relative Humidity 0-70oC 95% (see note 6)
Storage temperature -55 to +80oC
NOTES
1. With 4% engine governing.
2. After 10 minutes.
3. Applies to Mod status D onwards. Generator de-rate may apply. Check with factory.
4. Factory set, semi-sealed, jumper selectable.
5. Any device connected to the analogue input must be fully floating (galvanically isolated from ground), with an insulation strength of 500V ac
6. Non condensing.