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ACB Tripping settings

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ACB tripping settings   Acb has 6 adjustable tripping settings 1 Long time delay (Tr ) 2 Short time delay( Tsd ) 3 Earth fault delay (Tg) 4 Long time (Ir) 5 Short time (Isd) 6 Earth Fault (Ig) Long time is for maximum overload capacity . Short time is for short circuit current Earth fault is for earth fault current . As per thumb Rule : 1. Long time set at 0.8 means 80% of full load current .Until this level of current  breaker carry without tripping  . Above 0.8 Acb trips. Long time delay causes the breaker to wait for certain time to allow heavy temporary inrush currents to pass away. Generally long time delay is set at  4 Sec. 2. Short time set at 0.6 means  60% of full load current . It determines the Amount of Current the Breaker will carry for short time period.  Generally short time delay set at 0.2 sec. 3. Earth Fault set at 0.3 or 30% of  fault current . It controls the amount of Ground Fault current that will caus...
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Transformer Magnetic Oil Gauge Indicator

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conservator tank oil level (Mog) The MOG  (Magnetic Oil Gauge)  is a device by which we can supervise the level of oil inside the tank or conservator of power transformer and also gives us an alert low oil level indication .  A decrease in level of Transformer oil in Conservator is an indication of leak and therefore MOG level is an important parameter to be monitored. Practically under running condition oil level remains at 3/4 th level.
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PROTECTIVE RELAY

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Classification of Protective Relays : Based on Technology : Relay Classification Relays are broadly classified into 4 types based on technology used in manufacturing and based upon mode of operation , Sensing the fault  and giving Trip indication to circuit breakers . These Protective Relays are used in HT & LT Applications ,  HT applications in 33 KV side and in LV side 440 Volts . ELECTRO-MAGNETIC RELAY  :  Works on principle of  Electro - Magnetic Attraction . Based on amount of current flowing in the coil , Electromagnetic force is developed that will be exerted on moving armature. There  are 2 types of Electromagnetic Relays Presently used in Industrial & Commercial  applications . Induction Disc Type Relay  . Plunger Type Relay . 1.1 Induction Disc Type Relay : Induction Disc type Relay Relay consists of 2 Electromagnets , Disc , Moving contact and fixed contact , plug setting multiplier . 2 Windings are connected to 2 electroma...
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