MCC Panel is a panel which houses the switching starters of various motors of different sizes. The starters could be DOL or Star Delta or VFD depending on the rating and type of the motors. The selection of rating of components of the starters are based on the co-ordination chart of the switchgear manufacturer. Star-Delta method is adopted in motors feeders where high starting current is not acceptable. In case, controlled speed and adjustable speed of motors is desired for any application by the userVFD can be considered.
Fused Protection‘Switch Disconnection Fuse’(SDF)or Fuseless‘MouldedCase Circuit Breaker’ (MCCB)/ ‘Motor Protection Circuit Breaker’ (MPCB) are provided for short circuit protection of motors.
HRC fuses in SDF are the most effective and common method adopted by industries. SDF can provide least time to cut off the fault and is an economic back-up protection device. It can even be used to isolate the power circuit.
Though MCCB is used for protection of distribution circuits but with the latest technological development of current limiting MCCBs, these can also be used as an alternate to SDF units. Though it could work outto be costlier compared to SDF, it has the advantage of lower outage time in case of tripping and flexibility compared to SDF.But unquestionably the cut-off current of MCCBs is higher compared to HRC fuses in SDF units.
MPCB is yet another alternate for back-up protection. It could be used for direct switching of a motor, as acost-effective solution. But the electrical life of MPCB is limited when compared to PowerContactors. However,MPCBs can be effectively used with contactors as it has thermal as well as short circuit protection and can trip even smaller overloads, while the contactor will take care of the switching.
While using MCCB/MPCB to avoid spurious tripping, instantaneous release is chosen at higher than 12 times the full load current of the motor and generally the starting current of the motor is around 6 times the full load current.
Motors are the lifeline of every industry and hence need to be adequately protected against overloading, single phasing and unbalance voltage. Studies have shown that most motors fail due to electrical faults rather than manufacturing defects. Hence it is of utmost importance to have an appropriate motor protection device. Thermal overload relays are provided to protect the motors from electrical faults. Selection of such relays is done as per selection coordination chart of the manufacturers.
MCC Panelscan be constructed in either single front or double front type depending on the space requirement, orientation and need of the client.Busbar arrangement must be rigid and sufficiently supported.Busbars can be of either copper or aluminium material with proper earthing arrangement at 2 points in the complete panel. Separate compartments are provided for both cable entry and busbar connection. Incoming of the panels are provided with switch, meters and indicating lamps. Outgoing feeders can also be provided with meters if the clients so desire. The panels are of compartmentalised design and with approved paint finish.