A stepper motor’s purpose is to rotate through a precise angle and halt. The speed and torque of the rotation are secondary concerns. As long as the stepper rotates through the exact angle and stops, its mission is accomplished. Each turn is called a step, and common step angles include 30°, 15°, 7.5°, 5°, 2.5°, […]
Stepper Motor Control Because VR steppers are so scarce, this article focuses on controlling PM and HY steppers, which are almost always two-phase motors. Some PM and HY steppers are bipolar and have four wires. Others are unipolar and have five or six wires. The terms bipolar and unipolar identify how the wires are connected
The twentieth century brought about a revolution in electronics, as researchers used solid state physics to miniaturize transistors and other circuit elements. With these new integrated circuits, engineers were able to design systems more complex than anything dreamed of before. As circuit designs grew in complexity, so did the designs of electric motors. In 1962,
Metal-core printed circuit boards or MCPCB are increasingly being used in power electronics due to their superior thermal performance. Effective thermal management is critical to ensure the long-term reliability of power electronics, and thermal simulation and optimization can be used to improve the thermal performance of MCPCBs. This article discusses the importance of thermal simulation
Transient Performance of Stepping Motors Step Response It was pointed out earlier that the single-step response is similar to that of a damped second-order system. We can easily estimate the natural frequency ωn in rad/s from the equation Knowing ωn, we can judge what the oscillatory part of the response will look like, by assuming
Drive Circuits and Pull Out Torque Speed Curves Users often find difficulty in coming to terms with the fact that the running performance of a stepping motor depends so heavily on the type of drive circuit being used. It is therefore important to emphasise that in order to meet a specification, it will always be
Characteristics of Stepping Motors Static Torque–Displacement Curves From the discussion in previous article, it should be clear that the shape of the torque–displacement curve, and in particular the peak static torque, will depend on the internal electromagnetic design of the rotor. In particular the shapes of the rotor and stator teeth, and the disposition of
Stepping motors are attractive because they can be controlled directly by computers or microcontrollers. Their unique feature is that the output shaft rotates in a series of discrete angular intervals, or steps, one step being taken each time a command pulse is received. When a definite number of pulses has been supplied, the shaft will
Switched Reluctance Motor Drives The switched reluctance drive was developed in the 1980s to offer advantages in terms of efficiency, power per unit weight and volume, robustness and operational flexibility. The motor and its associated power-electronic drive must be designed as an integrated package, and optimised for a particular specification, e.g. for maximum overall efficiency
Operation of Synchronous Motor Drives As soon as variable-frequency inverters became a practicable proposition it was natural to use them to supply synchronous motors, thereby freeing the latter from the fixed-speed constraint imposed by mains-frequency operation and opening up the possibility of a simple open-loop controlled speed drive. The obvious advantage over the inverter-fed induction