Open Circuit Fault
An open-circuit faults is due to a break in the conductor, as at A (Fig), so that current cannot flow.
Effects:- An Open circuit fault will not allow the motor to start. If the fault occurs in 1 phase when the motor is running, the current in other two phases will increase and burn out the motor
How to Find:- Earth one end of the wire and using a Megger, check between wire at different points and earth. If the megger reading is infinity then we can conclude its an open circuit fault.
A Short-Circuit fault is due to a double break in the insulation, as a C (Fig), allowing both conductors o be connected so that a very large current by-passes or short circuits the load.
Earth Fault
An Earth Fault is due to a break in the insulation, as at B (Fig) allowing the conductor to touch the hull or an earthed metal enclosure.
Effect:- An earth fault provides an easy path for current to flow through the wires and earth
How to find:- Check the resistance Between terminal and earth. A reading of less than infinite indicates the fault.
You Can Answer Following Questions,
> What is open circuit fault
> What is closed circuit fault
> What is Earth fault
> Draw the diagrams of circuit faults
> How to find the open circuit faults, Short circuit faults and Earth fault
> What will be the megger values
> Difference between earth fault, open circuit fault and short circuit fault
An open-circuit faults is due to a break in the conductor, as at A (Fig), so that current cannot flow.
Effects:- An Open circuit fault will not allow the motor to start. If the fault occurs in 1 phase when the motor is running, the current in other two phases will increase and burn out the motor
How to Find:- Earth one end of the wire and using a Megger, check between wire at different points and earth. If the megger reading is infinity then we can conclude its an open circuit fault.
Must Read:> Single Phasing Causes Effect And Protection
Short Circuit FaultA Short-Circuit fault is due to a double break in the insulation, as a C (Fig), allowing both conductors o be connected so that a very large current by-passes or short circuits the load.
Effect:- A Short circuit fault will cause high current to flow in the wingdings which may burn out
How to find:- Remove the terminals at the panel. Turn all switches for that circuit to ON position. Check for resistance between positive and negative sides of the conductor using megger or multimeter. A reading of less than infinite indicates the fault.
An Earth Fault is due to a break in the insulation, as at B (Fig) allowing the conductor to touch the hull or an earthed metal enclosure.
Effect:- An earth fault provides an easy path for current to flow through the wires and earth
How to find:- Check the resistance Between terminal and earth. A reading of less than infinite indicates the fault.
You Can Answer Following Questions,
> What is open circuit fault
> What is closed circuit fault
> What is Earth fault
> Draw the diagrams of circuit faults
> How to find the open circuit faults, Short circuit faults and Earth fault
> What will be the megger values
> Difference between earth fault, open circuit fault and short circuit fault