LD Power: Transformer,Transformers, Rectifiers, Delhi, Noida, India

Servo Controlled Automatic Voltage Controller (Stabilizer)

Voltage fluctuation is a common phenomenon in every part of the country. Automatic Voltage Controller (Stabilizer) is an equipment to obtain constant voltage tram flucfuating supply system. The industrial units running round the clock usually face the problem of low & high voltage. 90% of industrial load is of motors. Electric motors draw considerably high current at low & high voltage. This higher current affects the electric motors (particularly smaller capacity motors upto 7.5 H.P.) in these ways: . Higher current produce higher losses in Electric motors which cause premature failure of winding.

Higher current produce higher losses in Electric motors which cause premature failure of winding.
These higher current of Electric motors also increase losses of Cables, Switches, Transformer & other associated equipments.
This higher current of Electric motors require 15-20% higher setting of over load relay to avoid frequent tripping of motor's starter. Higher setting of over load relays have very little safety margin against single phasing and over loading conditions.

the installation of the stabilizer and maintaining 390/400 volts, the motor will operate smoothly drawing 15-20% lesser current and corresponding the relay setting can be reduced by 15-20%. In case single phasing occurs, the relay will trip in 40-50 seconds. The motor can withstand the high current for this period and will be safe. Also, the relays, contactors, switchgears , etc. incorporated with the motor will be safe.

Description of Servo Controlled Automatic Voltage Controller

Advantages

Approximate quantitative advantages of automatic voltage controller at various fluctuation levels

Input Voltage Variation % Reduction in Breakdown Possible Appor. Power Saving Possible

Motor Load Below 10 HP. Lighting Load Motor Load Below 10 HP. Lighting Load

380-400 volts Nil Nil Nil Nil & no Servo Stabilizer Required

380-420 volts 5% 10% 3% 5%

380-440 volts 10% 20% 5% 10%

380-460 volts 40% 40% 7% 20%

380-480 volts 60% 60% 10% 30%

Technical Specification

Servo Stabilizers are available in a wide range and various models. The standard three phase models are suitable for balanced & unbalanced supply and loads. The standard models confirm to the following specification :

Input Voltage	360-460 V	340-460 V	320-460 V	300-460 V
Efficiency (Approx.)	99.5%	99%	98.7%	98.5%
Output Voltage	400 V t 1 %, 3 Phase, 50 Hz
Cooling	Naturally Oil Cooled
Type	Indoor
Temprature Rise (Max.)	30° C above ambient
Mounting	class=matterOn Uni Directional Wheel
Wave From Distortion	Virtually Nil
Duty Cycle	100% Continuous

Suggestion For Industrial Units Having OLTC
The units which have already installed OLTC with their transformer, also require stabilizer due to the reason that the tapping of OLTC is not changed frequently. It is changed only when the problem of very high or very low voltage is telt. On the other hand. the stabilizer continuously monitors the output voltage level. However the Input voltage range ot stabilizer can be kept low where OLTC is installed.