25-06-2012, 04:44 PM
VOLTAGE FLUCTUATIONS
VOLTAGE FLUCTUATIONS.ppt (Size: 1,020.5 KB / Downloads: 73)
DEFINITION
Due to undesirable external voltage changes like the AC line dropping out occasionally the DC or input signal will become a variable voltage that is referred as voltage fluctuation”
CAUSES OF VOLTAGE FLUCTUATION
Large equipment start-up or shutdown,
Sudden change in load,
Improper wiring,
Improper grounding,
Improper utility protection devices,
Due to improper welding,
SOLUTIONS:
Verify proper electrical connections and wiring;
Relocate equipment;
Reduce voltage motor starters;
Uninterruptible power supply;
Voltage ride-through equipment;
By proper welding at joints.
SERVO VOLTAGE STABILIZER.
INTRODUCTION
Single Phase Servo Voltage Stabilizer is one kind of a products which consist of contact auto voltage regulator, servo motor, automatic control circuit and etc. When the voltage fluctuates or the load varies, automatic sampling control circuit will send signal to drive the servo motor which can adjust the position of carbon brush of auto voltage regulator, then the output voltage will be adjusted to rated value and get a steady state.
OPERATION
The unit contains a regulation control PCB card that continuously senses the output voltage of the unit.
The card compares this voltage to a reference voltage using a comparator circuit which is used to switch relays controlling the mains supply to the drive motor on the variac.
The reference voltage is adjusted higher or lower by the comparator circuit output to prevent the motor drive from continuously oscillating around a fixed voltage point.