A motor control centre (MCC) is a structure used to centrally regulate some or all electric motors. It is made up of several covered parts connected by a common power bus, each of which has a combination starter that includes a motor starter, fuses or circuit breakers, and a power disconnect. Pushbuttons, indication lights, variable-frequency drives, programmable logic controllers, and metering equipment can also be found in a motor control centre. It might be linked with the building’s electrical service entrance. Almost all machine control systems have the same pattern and they run of similar mechanism of motor control. It is very important to have minute and fundamental knowledge about this system before plunging in this pursuit.
Motor control centres often control low voltage three-phase alternating current motors with a voltage range of 208 V to 600 V. Large motors running from 2300 V to about 15000 V need the use of medium-voltage motor control centres, which have separate chambers for power switching and control and use vacuum contactors for switching.
A motor control centre, often known as an MCC, is a grouping of one or more enclosed sections that share a power bus and are mostly made up of motor control units. Every machine control systems comprises of a motor control that execute the functions of the machinery aptly. We can apply this concept for all types of machinery used in households and industry also. Variable Frequency Drives, programmable controllers, and maybe the first place where electricity will enter the plant, can all be found in a motor control centre.
Since 1950, when there were a lot of electric motors being employed by the vehicle industry, motor control centres have been in use. They are utilised in several industrial and business applications nowadays. In order to shield the motor control centre from corrosion and dust, it is frequently housed in a separate air-conditioned room. Other times, the motor control centre will be positioned on the plant floor close the machinery
What make up a motor control center’s primary parts?
- A bus bar
- Breaker for circuits
- Contactor magnetic
- Additional contact on a contactor
- Control by relay
- Transformer in command
- Control panel enclosure for cable installation
- Switch limit
The main purpose of a bus bar, which is a bar made of brass, copper, etc., is to supply or distribute the necessary power to the electrical equipment. Therefore, the bus bar in an MCC would serve as a power distributor. The main benefit of employing a bus bar in an MCC is that we can do away with the wiring of multiple components, which reduces both the size and the number of parts in the MCC. So, with the aid of a bus bar, we can quickly connect the electrical equipment in an MCC, and this would also be helpful to find the fault. We can quickly identify and fix issues with
These relays would safeguard the motor from overheating, which could be brought on by the driven machinery being overloaded. It may also result from low voltage or from a three-phase system with an open phase. Consequently, the overload relay would open and the motor would be disconnected from the power source when the excessive current was drawn for a predetermined amount of time. This relay would permit momentary overloads that couldn’t harm the motor while disabling permanent overloads that would.
Miniature circuit breaker
The MCB’s function is to cut off a circuit in the event of an excessive current flow or an electrical load that is greater than the circuit’s capacity.
The control circuit may occasionally need to run at lower voltages than the power circuit. Therefore, a control transformer can be used to lower the voltage level.
What factors need to be taken into account while installing a motor controller?
Electrical service: We must determine if the service is AC or DC; if AC, frequency and the number of phases must also be taken into account in addition to voltage.
Motor: The motor needs to be linked to the electrical service, and if it has an HP rating, it needs to be properly sized for the machine load. The motor’s speed and torque must also be taken into account.
According to the requirement, the controller should be able to start, stop, and reverse the motor activity.
The controller must be installed in a location where it won’t be harmed by elements like rain, snow, dirt, oils, or lubricants.
How should a motor control centre be chosen?
When choosing the Motor Control Center, we should take into account its ampacity, which is the highest amount of current that a horizontal bus can support.
While making our choice, we must also take into account the available fault current level, which is essentially the amount of current that would flow in the event of a short. Additionally, the busing material utilised for electrical busing needs to be taken into account.
Another crucial component of an MCC is the feeder cable, and we must take into account how it is linked to the MCC. The connection would come in two varieties: an overhead way and a subterranean method. the electrical wires that would power the MCC
There will be a controller on every electric motor. Depending on what the motor is doing, the motor controller will have a variety of alternatives. A motor controller is a tool used to monitor an electric motor’s operation.
A motor control centre serves a very simple purpose. It is a large enclosure designed primarily to contain common motor control machinery. Plug-in units hold the motor controls. The motor controller may provide a manual or automated start/stop option for the motor as well as safety safeguards to guard against overloads.
A smart MCC can speed up commissioning while lowering the cost of labour and installation supplies. Installation and commissioning are made simpler and faster by equipment that can integrate with existing systems and support popular network protocols and controllers. Further reducing project deadlines is possible by factory configuring the MCC to individual project specifications, such as IP address, motor data, protective measures, and other characteristics.
Intelligent MCCs can contribute to improved employee safety through enhanced information and remote monitoring and control features. Personnel may more easily acquire information about the condition of the system and its operation while avoiding the arc flash boundary to minimise exposure to powered equipment.