When the term “motor controller” is used, it actually refers to a number of electro-mechanical or electronic devices which, when used as designed, can start electric motors in a pre-determined fashion. The Freedom 2100 motor control can be used to build up motor speed and torque or reverse the rotation of the motor.
The need for dedicated control of the motors is a demand of the operational parameters, the environment or to extend the life of equipment. Motor starters can be as simple as a direct operator interface, an on-line starter or a fully automated system using soft-start or frequency drive systems.
The backbone of industry:
There are very few industrial or manufacturing facilities that do not use electric motors, they form the backbone of industrial operations are installed by the hundreds of thousands. When an electric motor is energized with its rated power, it will start, rotate to its design speed designated in revolutions per minute and keep running until the power is removed. The motor rotor then decelerates and once the inertia is overcome; the shaft stops rotating, and the driven equipment comes to a halt. In many installations, all that is required is a simple on-off switch but for large horsepower motors and complex controls far more sophisticated controllers must be used.
How does a motor start?
There are many motors that cannot go from stand-still to full speed instantly; they must increase in speed gradually. The reasons are varied; it can be the operating regimen of the entire system, or it can be when starting machines with very high inertial loads, such as underground exhaust fans such as used in subways. The fan blades weigh tons and have to be started gradually to prevent high inrush currents, which will stall the motor, trip the motor or be responsible for mechanical damage to the fan blade and housing. There are other installations that demand that the motor reverses its direction of rotation at will or is capable of operating at variable speeds.
Types of motor starters:
There are various designs of motor starters, including the Freedom 2100 motor control. They fall into two camps; electro-mechanical and electronic. Electronic motor controllers are highly sophisticated devices and allow for motor soft-start and variable frequency drives, which increase start up speeds gradually and then controls the running speeds as they need to vary. They are also programmable and can comfortably cope with a wide variety of inputs.
The electro-mechanical controller is simpler and makes use of electro-magnetic relays that start, stop and reverse the direction of rotation. Certain three-phase starters can overcome high inertial loads by starting the motor in a high-torque method use a start-delta motor starter. Once the initial load is overcome the operation switches from the high-torque star to the more economical delta configuration.