Townsley Electrical is highly trained in PLC motor control diagnostics and repair and can troubleshoot most electronic PLC assemblies down to the component level. From processors to I/O, we are ready to handle your industrial repair needs.
If you need a turnkey automation solution that includes panel design, assembly , programming, test and start-up, we can provide it. Many types of machinery or production lines require custom control panels with different types of motor control systems. We carry many different types of the common components to perform emergency repairs or simply the addition of controls for new equipment.
Every electric motor has to have some sort of controller. The motor controller will have differing features and complexity depending on the task that the motor will be performing. Motor controllers can be manually, remotely or automatically operated. They may include only the means for starting and stopping the motor or they may include other functions.
A small motor can be started by simply plugging it into an electrical receptacle or by using a switch or circuit breaker. A larger motor requires a specialized switching unit called a motor starter or motor. When energized, a direct on line (DOL) starter immediately connects the motor terminals directly to the power supply. Reduced-voltage, star-delta or soft starters connects the motor to the power supply through a voltage reduction device and increases the applied voltage gradually or in steps.
A reversing starter can connect the motor for rotation in either direction. Such a starter contains two DOL circuits—one for clockwise operation and the other for counter-clockwise operation, with mechanical and electrical interlocks to prevent simultaneous closure.
A starter will contain protective devices for the motor. At a minimum this would include a thermal overload relay. The thermal overload is designed to open the starting circuit and thus cut the power to the motor in the event of the motor drawing too much current from the supply for an extended time. The overload relay has a normally closed contact which opens due to heat generated by excessive current flowing through the circuit. Thermal overloads have a small heating device that increases in temperature as the motor running current increases.
Motor Control Centers (MCC)
A motor control center is an assembly of one or more enclosed sections having a common power bus and principally containing motor control units.[Motor control centers are in modern practice an assembly of several motor starters. A motor control center can include variable frequency drives, programmable controllers (PLC), and metering and may also be the electrical service entrance for the building. Motor control centers are usually used for low voltage alternating current motors from 230 V to 600 V. Medium-voltage motor control centers 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.
Programmable Logic Controllers (PLC)
A programmable logic controller is a used for of processes, such as control of machinery on factory, amusement rides, or. PLCs are used in many industries and machines. Unlike general-purpose computers, the PLC is designed for multiple inputs and output arrangements, extended temperature ranges, immunity to electrical noise, and resistance to vibration and impact. Programs to control machine operation are typically stored in battery-backed-up or non-volatile memory. A PLC is an example of a hard real time system since output results must be produced in response to input conditions within a bounded time, otherwise unintended operation will result.