Answer / bala murugan

In ordinary stabilizer, the transformer has number of
tappings or windings. With the help of relays, the
appropriate tapping can be switched to give output voltage
that is nearly equal to the line voltage required.
But in servo stabilizer there is an error anplifier to
give an error voltage. This vjoltage is got by subtracting
the dc reference vjoltage Cref and dc voltage rectified
from the output line. This voltage drives the servjo motor
in a direction to boost or buck the output voltage from the
secondary of the transformer.
Since the error amplifier continuously monitors the
output voltage, we get constant voltage output. By
adjusting the value of Vref, we can set the desired output
voltage.

Answer / siddhu

The SERVO CONTROLLED VOLTAGE STABILIZER utilizes a motor
driven variable
auto transformer & a Buck\Boost transformer. Which is
connected between the incoming
phase supply & the load. The primary winding of the Buck \
Boost transformer is
connected to the continuously Variable Auto Transformer in
such a way that One lead of
the winding is connected to a predetermined tap point of
the auto transformer,
depending on the position of the variable brush arm with
respect to the fixed point the
voltage applied to the primary winding has addition or
subtraction on the supply voltage
available on the secondary side.

The autotransformer is driven by an AC synchronous motor to
achieve increase or
decrease in output set voltage by rotating it in clockwise
or anticlockwise direction
depending on the input supply voltage.
An electronic control card continuously monitors the
output voltage and the same is
being compared against the set reference voltage to achieve
the desired output voltage.
The control card responds to the variation in input voltage
in such a way that the motor
in voltage correction doesn’t overshoot in either
direction. This method of correction in
output voltage is free from generating waveform distortion
& harmonics.

Answer / thowsif_emerson

This is a stabilizer. which constantly monitors the output
voltage and controls the variations in the input voltage
by movements of a motor. This motor in turn selects the
proper output voltage on the variable transformer (variac).
This is probably the cheapest power-conditioning product
available. It gives reasonably good voltage regulation and
is all right where voltage fluctuations are not
considerable. However it is not advisable to use it outside
big cities where apart from considerable fluctuations in
voltage, the power is full of frequency drifts, failures,
noise and spikes.

why we test the core balance of the transformer?

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