MCC Motor Control Centre Panels

Industries need a secured area to have a control on all their machines. This is necessary to manage their day to day activities and maintenance. To serve this purpose, a Motor Control Center (MCC) has been designed. MCC is an assembly of several motor starters, which have the common power bus and primarily containing motor control units. This panel is an

This panel is an engineered assembly with internal control and interlocking wiring to a central control terminal panel board or programmable controller. A motor control centre can include variable frequency drives, programmable controllers and metering and may also be the electrical service entrance to the building.

MCC consists of feeders for motors and blowers. Feeders are designed according to the motor rating. In most of the MCCs, auto/manual provision will be there. With manual provision, motors can be operated manually. In auto provision external signal is required to start the motor. The signal is given by the control panel. Indicators for the motor operation

also will be present in the control panel. A combination starter is a single enclosure containing the motor starter, fuses or circuit breaker, and a device for disconnecting power.

We will now look into what controls does an MCC give regarding voltage range, the usage, what are the components and specifications of MCC and how does it help in Fire protection.

Motor control centres are usually used for low voltage three-phase alternating current motors from 208 V to 600 V. Medium-voltage motor control centres are made for large motors running at 2300 V to around 15000 V, using vacuum contactors for switching and with separate compartments for power switching and control.

Motor control centres have been used since 1950 by the automobile manufacturing industry which used large numbers of electric motors. Today they are used in many industrial and commercial applications. Where very dusty or corrosive processes are used, the motor control centre may be installed in a separate air-conditioned room, but often an MCC will be on the factory floor adjacent to the machinery controlled.

A motor control centre consists of one or more vertical metal cabinet sections with a power bus and provision for plug-in mounting of individual motor controllers. Very large controllers may be bolted in place, but smaller controllers can be unplugged from the cabinet for testing or maintenance. Each motor controller contains a contactor or a solid-state motor controller, overload relays to protect the motor, fuses or a circuit breaker to provide short-circuit protection, and a disconnecting switch to isolate the motor circuit. Three-phase power enters each controller through separable connectors. The motor is wired to terminals in the controller. Motor control centres provide wire ways for field control and electricity cables.

Each motor controller in an MCC can be specified with a range of options such as separate control transformers, pilot lamps, control switches, extra control terminal blocks, various types of thermal or solid-state overload protection relays, or different classes of power fuses or types of circuit breakers. A motor control centre can either be supplied ready for the

customer to connect all field wiring or can be an engineered assembly with internal control and interlocking wiring to a central control terminal panel board or programmable controller.

Motor control centres usually sit on floors, which are often required to have a fire-resistance rating. Fire stops may be necessary for cables that penetrate fire-rated floors and walls.