Direct Current Motor Control
Motor controller is a device or group of devices that can coordinate in a predetermined manner the performance of an electric motor. A motor controller might include a manual or automatic means for starting and stopping the motor, selecting forward or reverse rotation, selecting and regulating the speed, regulating or limiting the torque, and protecting against overloads and electrical faults.
The main objective of using a motor controller instead of using a simple mechanical switch is to control the speed, start/ stop and rotation of the motor in a more accurate way. The limitation of a mechanical switch is the current limit. A big electric motor can draw up to 30Amp and above were most of the switches are unable to take it. Furthermore we are unable to control the motor speed using pulse- width modulation (PWM). The most common motor controllers in the market are using H-bridge circuit where we are able to control a large motor using a small signal.
DC motors are still relevant in modern industry, even though they are one of the oldest electric motor designs. How have they stood the test of time, especially against all the amazing new machines of the 21st century?
There are many potential answers to this question, but their good controllability is a major reason why DC motors have persisted. This simple machine transforms DC current into mechanical rotation, which can be controlled by simply changing the input voltage or reversing its leads. The elegance of DC motors has led to the production of many DC motor controllers, which are often simple in design and provide adequate performance for their cost.
What are DC motor controllers?
Simply put, a DC motor controller is any device that can manipulate the position, speed, or torque of a DC-powered motor. There are controllers for brushed DC motors, brushless DC motors, as well as universal motors, and they all allow operators to set desired motor behavior even though their mechanisms for doing so differ.
Our articles on shunt DC motors, series wound DC motors, and brushless DC motors provide detailed explanations on how DC machines function. To briefly summarize, the speed/torque curve of DC motors are inversely linear, meaning their torque proportionally decreases as the motor RPMs increase. This allows for easy control, as lowering the speed will increase the torque, and vice versa. Also, unlike some AC motors, DC motors are easily reversed by simply switching their leads so that the DC current runs in the opposite direction.