• Pruftechnik Dieter Busch

Voltage Monitoring Devices

Prok Devices offers voltage monitoring devices for protection against under-voltages, over voltages, phase failure, phase sequence (reversal), and unbalanced voltages in electrical equipment. These are available in six models, ie, VD-01, VD-02, VD-03, VD-04, VD-05 and VD-06, for various applications. They are provided with Auto Reset and Time Delay (fixed and variable) functions, in addition to Manual Reset. In motors operating at low loads, failure of any one phase causes over-voltages, which may cause rupture of insulation leading to motor burn out. Low voltage will cause synchronous motors to come out of synchronisation at 75% of rated voltage. Induction motors may stop when voltage falls below 70%. Over-voltage may occur due to defective voltage regulator, and over speeding is caused by sudden drop in load. In single phase supply, low voltage causes over load on supply cable and thermal damage to insulation of windings. All these eventualities can be avoided by using these devices.