Motor Control Center
Seamless Process Automation design and assemble wall-mounted, floor-mounted and free-standing modular certified type-tested motor control panels. Popular motor starters are;
- Direct-on-line (DOL)
- Star-delta starter
- Soft-starter
- Variable speed drive
Small-rated motor can be started by using a circuit breaker, manual starters. However, large motors require specialized controllers.
Direct-on-line (DOL) starters, mostly straight-forward motor starters, directly connect to motor terminals when energized. DOL starter contain protective devices that monitor motor conditions.
Softstarters or reduced-voltage starters use regulators to connect the motor to power supply. These regulators gradually increase voltage in steps.
Asynchronous motors draw extremly high startup current before reaching full speed, usually exceeding 6 times full load current.
Variable speed drive is used to reduce current inrush and minimize voltage dips in its power supply. The use of VSDs not only reduces running cost but increases equipment life through less wear and tear, this help reduce preventive maintenance and reduce greenhouse gas emissions.
Forward-Reverse starters are used for motor whose rotation is in forward or reverse. These starters use two circuits, for forward and reverse operations. Mechanical and electrical interlocks are used to prohibit concurrent engagement.
Autotransformer starters permits voltage reduction at motor terminals, thus reducing inrush currents and starting torque. When the motor reach predetermined speed, based on elapsed time, or when triggered by a current sensor, full-voltage is applied to the terminals.
Drive System
Start up and system check for condensing unit, the system starts beautifully with Variable Speed Drive ramp and is able to provide frequency operational range from 0-70hz. The Danfoss drive mounted on IP54 enclosure and have the displays mounted on the control board so all pressures and temps can be monitored from the condensing unit.
Major variable speed drive include
Summary of Motor Control Functions
Whether the application of the motor control is manual or automatic, simple or complex, used to regulate torque or speed, or as a preventive measure against motor damage, motor controls are critical in commercial industry applications that use electric motors for their operations.
