Electricity + Control July 2017

Electricity

Control

JULY 2017

hink about what happens when you switch

on your kettle in the morning. Apart from the

encouraging noises it makes, indicating that

coffee is not far away, all kinds of clever things are

going on inside the kettle’s electrical circuitry.

Every electric motor has a controller, and these

controllers differ in complexity and number of fea-

tures depending on the job they need to do. In

the case of your kettle, the controller is the on/off

switch, and you manually operate it so that your

kettle can perform its very important task.

Now imagine you had to make a thousand cups

of coffee, and needed to switch on 500 kettles all

at the same time. Not easy. In fact, pretty impos-

sible. This is why MCCs are such vital pieces of

equipment, controlling everything through a cen-

tralised system.

In its simplest application, an MCC is a panel

that works as a motor starter for several automat-

ed or semi-automated machines. Comprising one

or more enclosed sections with a common power

bus, an MCC can include variable frequency drives,

programmable controllers and metering. Essen-

tially, they are a type of electrical ‘filing cabinet,’

with ‘drawers’ full of lighting contactors, combina-

tion starters and other electrical control and distri-

bution products. Each section, or motor controller,

of the cabinet has a built-in safety mechanism to

protect the motor. These can be solid-state over-

load protection relays, fuses or a circuit breaker,

and there is usually a disconnecting switch as well

to isolate the motor circuit.

While they were first used in car manufactur-

ing, today MCCs are found in numerous commer-

cial and industrial applications, specifically where

there are multiple, remotely controlled loads linked

to a central control point.

Conclusion

Modern MCCs offer a host of benefits, including:

•

Reduced downtime:

Standardised sections

mean a simpler design, so operators require

less operational training. Plug-in units can be

easily swapped out for maintenance or re-

placement, and the inherent isolation of MCC

units means they can safely be serviced indi-

vidually, within legislated guidelines, without

switching off adjacent units

•

Quicker, cheaper installation:

MCCs have

their own factory-wired and tested units and

power buses, so field wiring and testing are

minimised

•

Flexibility:

MCCs can be easily expanded by

adding new units and sections

•

Space saving:

Much more compact than

mounting individual devices

JB Switchgear is known in the industry for de-

signing and manufacturing high quality switchgear

solutions that meet the latest national and interna-

tional safety and performance standards.

The company offers a comprehensive range of

fixed, de-mountable and withdrawable MCCs, so

talk to us about how we can help you get the solu-

tions you need.

Motor Control Centres

How They Work

Johan Basson, JB Switchgear

Motor Control Centres (MCCs) have been around since the 1950s when they were

first used by the car manufacturing industry, which needed many electric motors.

DRIVES, MOTORS + SWITCHGEAR

<<Author>>

Johan Basson is the

Managing Director of

JB Switchgear.

+27 (0) 11 027 5804 / +27 (0) 82 852 401

info@jbswitchgear.co.za www.jbswitchgear.co.za

An MCC is a panel that

works as a motor starter

for several automated

or semi-automated ma-

chines.

An MCC can include Var-

iable Frequency Drives,

programmable control-

lers and metering.

MCCs control everything

through a centralised

system.

Take Note!

abbreviations

MCC

– Motor Control Centre

VFD

– Variable Frequency Drive

Essentially,

an MCC is a

type of filing

cabinet.