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3. System power-up (Standard Version)
Before the system is powered-up for the first time the following checks should be carried
out by qualified personnel only.
A)
Inspect the input and output terminations for tightness, correct wiring and phase rotation.
B)
Check that the building electrical service is of sufficient capacity to supply the input current of the AVR,
remembering that this can be 40% higher than the output current to the load.
C)
Check building electrical service is of correct nominal voltage and wiring configuration and that main
circuit breakers are suitable for the inductive nature of the load represented by the AVR.
D)
Ensure that the load equipment is ready to be energised. Once the above conditions have been verified,
input power may be applied to the AVR. Once input power is applied the three digital voltage meters on the door
of the AVR should indicate a valid output voltage. If this is not the case switch off the power immediately and
refer to the troubleshooting section of this manual. The AVS indicators on the door (if fitted) should show 'on' (after
the wait time of 3 minutes).
3. System power-up (DS Version)
Before the system is powered-up for the first time the following checks should be carried out by qualified
personnel only.
A)
Inspect the input and output terminations for tightness, correct wiring and phase rotation.
B)
Check that the building electrical service is of sufficient capacity to supply the input current of the AVR,
remembering that this can be 40% higher than the output current to the load.
C)
Check building electrical service is of correct nominal voltage and wiring configuration and that main
circuit breakers are suitable for the inductive nature of the load represented by the AVR.
D)
Ensure that the load equipment is ready to be energised. Once the above conditions have been verified,
input power may be applied to the AVR. It is wise to apply power to the AVR with the input breaker in the 'on'
position and the output breaker in the 'off' position.
Once input power is applied the three digital voltage meters on the door of the AVR should indicate a valid
output voltage. If this is not the case switch off the power immediately and refer to the troubleshooting section of
this manual. The AVS indicators on the door should show 'on' (after the wait time of 3 minutes). When it has been
verified above that the AVR is functioning correctly, the incoming power should be switched off and the output
circuit breaker set to the on position. If power is now re-applied, the load will be automatically supplied when the
3 minute delay time has elapsed.
4. Functional Description
4.1 General Function
This three phase AVR is made up from three identical single phase regulator units. Each of these monitors its own
output voltage and adjusts for variations in mains supply voltage so as to maintain an output voltage within close
limits. When the AVS function is fitted the outputs from the regulators are connected through a
contactor to the load. The contactor is controlled by a three phase Automatic Voltage Switcher PCB which
monitors the AVR outputs. This connects the load only when all the phase voltages are within acceptable limits.
There is a delay between the time when all voltages come within limits and the contactor switching on. This is so
as to allow the supply to stabilise and to avoid repeated switching of the load on and off should the mains supply
be exceptionally erratic. The state of the AVS circuit is indicated on the front panel by three large LEDs, Green for
On, Yellow for Wait and Red for Off.
4.2 AVR Function
This is based on an auto transformer with tap changing on the output. There are seven taps to each transformer
giving an accurate output voltage for a wide range of input voltage. The taps are switched by generously rated
THREE PHASE AUTOMATIC VOLTAGE REGULATOR Issue: Jan 2016
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