faradays second law
2500 Amps
thanks ,it should be 400amps.
In a Molded Case Circuit Breaker (MCCB), I3 typically refers to the third current setting or rating, often associated with the overload protection function. It helps define the maximum current that the breaker can handle continuously without tripping. This setting is crucial for protecting the electrical circuit from overload conditions, ensuring safe operation, and preventing damage to equipment. Properly setting I3 helps balance the load and enhances the reliability of the electrical system.
An SPN MCCB is a Solid Pole Neutral Molded Case Circuit Breaker.
The difference between a tpn mccb and a 4 pole mccb is rather negligible. The only real difference is that a 4 pole mccb works a little bit faster and allows for a strong network connection. The connection with a 4 pole mccb is just a bit more reliable.
2500 Amps
ka of mccb=transformer(KVA)x100/1.732xsecondary voltagex%impedence of transformer
thanks ,it should be 400amps.
MCCB is actually the need to understand MCB is clear to most of the users.MCB is for low current interruptions and has fixed current rating for trip. It will not trip at earth fault. It has low KA rating, it is suitable for simple over current application, less than 100 Aand has low cost.MCCB (Molded case C.B) is for high current application normally above 100 A and also programmable/adjustable for earth fault, over/under voltage protections etc. It has high KA ratings,hence costly.Engrs-ift@hotmail.com
In a Molded Case Circuit Breaker (MCCB), I3 typically refers to the third current setting or rating, often associated with the overload protection function. It helps define the maximum current that the breaker can handle continuously without tripping. This setting is crucial for protecting the electrical circuit from overload conditions, ensuring safe operation, and preventing damage to equipment. Properly setting I3 helps balance the load and enhances the reliability of the electrical system.
An SPN MCCB is a Solid Pole Neutral Molded Case Circuit Breaker.
Basically tpn means the tripple pole + nutral protectin mbc .
what is the difference between utilization category A and B of MCCB's
there is three difference in ACB and MCCB, 1- ACB on off operation is easy as com pair to mccb because acb having charged spring force. 2- acb having much delay time period (category A) and mccb having low time period (category B) 3- the main diffidence is that acb having high raptching capacity and mccb are low.
want to know
The difference between a tpn mccb and a 4 pole mccb is rather negligible. The only real difference is that a 4 pole mccb works a little bit faster and allows for a strong network connection. The connection with a 4 pole mccb is just a bit more reliable.
To understand various considerations for proper co-ordination, time-current characteristics of thermal overload relay (curve B), H.R.C. fus (curve C), MCCB with only instantaneous release (curve D) and MPCB (curve E) are superimposed on motor starting characteristics (curve A) in Fig. 3. Intersection of characteristics of thermal overload relay and Fuse / MCCB is termed as 'cross-over point' and corresponding current as 'cross-over current' lco. Following points are to be ensured while selecting components to have properly co-ordinated motor protection: lContactor rating (AC-3) should be more than or equal to motor full load current (if application is AC-3 duty) Thermal overload relay of appropriate 'Trip Class' is selected. Time current characteristics of the relay should remain above motor starting characteristics as shown in Fig. 3. For fault currents lower than 'cross-over current lco', relay will respond faster than SCPD and hence contactor will interrupt the fault current. Fault currents higher than lco will be interrupted by SCPD. Hence, rating of contactor is so chosen that lco is less than rated breaking capacity of the contactor Relay and contactor should be able to withstand lco for a duration equal to trip time of the relay. IEC / BS / EN standards require that the contactor should be able to withstand at least current equal to 8 times AC-3 rating (6 times for ratings higher than 630A) for 10 seconds While using MCCB or MPCB, attention needs to be given to motor peak starting current. To avoid operation of MCCB / MPCB during starting, instantaneous release is chosen as 12 times the full load current of the motor. This thumb rule assumes motor starting current equal to 6 times full load current In case of high efficiency motors, starting currents could be about 8 times full load current. For such application, MCCB rating need to be selected such that instantaneous release setting is higher than 12 (about 14) times full load current to avoid nuisance tripping during starting. Similarly, while using MCCB as a SCPD for Star-Delta starter, consideration needs to be given to peak current associated with change over from Star to delta. Instantaneous release of MPCB is normally set at 12 times the rating. Hence, possibility of nuisance tripping needs to be considered while using MPCB for protection of high efficiency motors or for star delta starter.