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The Rotor Protection relay is used in synchronous motors and generators to identify the presence of an earth fault in the rotor winding. While the winding in the rotor is insulated from the ground during normal operation, the Rotor is subjected to stresses due to vibration, heat, etc. These stresses can cause the winding to give way in a particular place and the winding can get earthed.
While a single earthing in the winding is not immediately damaging. It sets the stage for damage if a second failure should occur. The second earthing can cause a short-circuit through the rotor causing extensive damage to the rotor and the winding.
The currents produced during a rotor earth fault can cause excessive vibration and disturb the magnetic balance inside the alternator. These forces can cause the rotor shaft to become eccentric and in extreme cases cause bearing failure.
Hence, it is necessary that any earthing in the rotor is detected at the earliest.
In slip ring rotors, carbon deposits on the slip rings may compromise the insulation resistance of the rotor. Hence, the slip rings need to be inspected for any deposits.
The Rotor Earth Fault Protection Device consists of a current injection device which applies an AC voltage to the rotor winding by means of a slip ring fitted on the rotor. The current is applied to the rotor through a coupling capacitor. In the normal condition, the system is floating and the current flowing through the device is zero as the resistance is high.
When a fault occurs, the current increases causing the relay to operate. The relay can be configured for alarm or trip depending on the criticality.
What else can I help you with?
In 3 pH Delta motor connection the upstream ACB is tripping due to ground fault protection while motor starts with soft starter why?
Check the earth fault trip off set limit of the ACB. It may be too low.
How do you calculate 3 phase earth fault loop?
You can't have a three phase earth fault, you can have a phase to phase or a phase to earth fault. If you want the potential phase to earth fault current it will be your voltage times your impedance. If you want the phase to phase potential fault current then you should just double the above result.
What is an Unrestricted Earth Fault?
I'm guessing this is in reference to a restricted earth fault, and you want to know what the opposite is? Restricted earth fault protection is designed to operate for earth faults within a specific zone. Unrestricted protection will operate for faults "anywhere", as long as the pickup can be satisfied. For example, REF (restricted earth fault) transformer protection looks for a small amount of neutral current, and if this exists, and the relay identifies this current as being within the zone of protection, the relay will trip. If it were unrestricted, the small amount of neutral current alone would be enough to cause a trip.
What is earth fault loop impedance?
An earth-fault loop is the path taken by the fault current, when an earth-fault occurs within an electrical installation, and comprises a series circuit made up ofthe utility company tranformer's low-voltage winding,the utility company's distribution cable's line conductor,the consumer's line conductor to the point of an earth fault,the consumer's earthing conductor,and the resistance of the earth path back to the transformer.The combined opposition of this series circuit to the flow of fault current is termed the earth-fault loop impedance, expressed in ohms.
Will earth fault affect batteries discharging in an equipment?
If one terminal of a battery is earthed (and, by this, we normally mean a 'chassis earth'), then an earth fault within the circuit supplied by the opposite terminal will result in the battery being discharged. The rate of discharge depends on the resistance of the earth fault.
What An abrupt shift in the earth along a fault cause?
Earthquake!
Why is your Ford Focus 2003 new starter working intermittently?
Fault with new starter motor Fault with immoboliser Fault with ignition switch or wiring Low battery charge Loose terminals battery/starter motor Bad engine earth.
What is a break in earth's crust?
A fault
How does an earth or ground fault affect 3 phase motors?
Three phase Delta motors can continue to operate when one phase has an earth (ground) fault, when the motors are powered from an ungrounded Delta or Wye (star) service. This feature can be helpful in agricultural and oil rig pumping because it allows the operation to continue until the affected motor can be replaced. Motors on a grounded service will trip and the pumping will stop immediately after one phase goes to ground.
Can earth fault current go up passing through the downstream panel and directly cause a trip at the upstream panel which have higher set point of earth fault protection?
If the fault is a direct short to ground, the fault current can be high enough to trip the upstream protection.
In 3 pH Delta motor connection the upstream ACB is tripping due to ground fault protection while motor starts with soft starter why?
Check the earth fault trip off set limit of the ACB. It may be too low.
What is a volcanic fault?
A volcanic fault is a fracture in the Earth's crust that occurs due to the movement of molten rock or magma beneath the surface. These faults can cause earthquakes and volcanic eruptions when there is significant pressure and stress built up along the fault line.
What is caused by sudden displacements along fault fissures in the solid and rigid layer of the earth?
Sudden displacements along fault fissures can cause tremors and earthquakes.
What is an earth fault relay?
An earth fault relay is a relay that is activated by a fault current that flows from the power line to the earth. Earth fault relays are found in power distribution systems.
What is the name of the earth crust along a fault line?
The section of the Earth's crust along a fault line is referred to as the "fault plane." It is the surface along which the rocks on either side have moved relative to each other. The movement can cause earthquakes and other geological activity.
Earth fault relay and an overcurrent relay Methods to energise an earth fault relay?
Earth fault relay and an over current relay Methods to energies an earth fault relay with simulation diagram?
What is the cause of quakes?
pressure is built on a fault line. the pressure is released by the earth's crust shifting and that causes earthquakes.
