Hi all,

For 80kA @ 690V System, I want to select MCCB+POWER CONTACTOR Combination as per type 2 coordination chart and i have to select 3RV13(MCCB) + 3RT(POWER CONTACTOR) with SIMOCODE(3UF7) Relay. but unfortunately i am not able to find type 2 coordination chart for the same.

Kindly help.

Please provide the application, connected load data, duty cycle & starting time, needs to select devices.

3RV is MPCB & not MCCB. 3RV provides o/c or single phasing protection to motor.

Please clear, do you want FUSES + MPCB or MCCB protection with type 2 co-ordination.

I need MCCB protection with type 2 co-ordination. Client requirement is MCCB, not MPCB.and our system is 80kA@690V.

If any chart is available for this selection that will be better.

Hi, Thanks for the help.

Can u please explain why we have to use limiter function for 1.1kW to 45kW motor?

With motor starters where the Iq of the whole combination is higher than the Icu of the circuit breaker (CB) the contactor assists the CB in clearing the short circuit in the same way as a limiter. It works the following way: In the event of a short circuit the upstream circuit breaker lets a certain current go through before it opens. The magnetic forces of this let through current lift off the contacts of the downstream contactor thus creating an arc. The resistance of this arc limits the short circuit current to a level which can safely be handled by the CB.

The short-circuit breaking capacity can be increased significantly with an upstream standard motor starter protector/circuit breaker with limiter function.

The motor starter protector/circuit breaker which is connected downstream must be set to the rated current of the load.

Hi All,

Please share the type-2 coordination considering fuse + thermal O/L relay + power contactor of 690V, 3Ph, 50hz, 65-80kA system.

Which is load?

Current rating?