Stepper Motor and Switched Reluctance Motor Drives

Stepper Motor and Switched Reluctance Motor Drives:

Advantage and Disadvantage of Stepper Motors : Advantage and Disadvantage of Stepper Motors are as follows; Advantages They are compatible with digital systems and do not require digital to analog conversion at the input, as do conventional servos, when used with digital systems or a computer. While simple open-loop control is good enough for the control of position and speed, it can also be used in closed loop position and speed control systems with either analog or digital feedback. A wide range of step angles is available off-the-shelf from most manufacturers, in the range of 1.8 to 90°. The range of torque is from 1 μNm …


Drive Circuits for Stepper Motor : A Drive Circuits for Stepper Motor is usually driven from a low voltage dc source. When a phase is to be energised, the dc source is connected to the phase by a semiconductor switch S (Fig. 8.9). The phase current builds up at the rate decided by the phase winding’s electrical time constant. When the phase is to be de-energised, switch is turned off, which transfers the current to freewheeling diode DF. The current drops to zero, again at the rate decided by the time constant of the phase winding. Motor torque, which is a function of …


Switched Reluctance Motor : The switched reluctance motor (SRM) has both salient pole stator and rotor, like variable stepper motor, but they are designed for different applications, and therefore, with different performance requirements. A stepper motor is designed to make it suitable for open loop position and speed control in low power applications, where efficiency is not an important factor. On the other hand a switched reluctance motor is used in variable speed drives and naturally designed to operate efficiently for wide range of speed and torque and requires rotor position sensing. It may also be noted that the switched reluctance motor …


Variable Reluctance Stepper Motor : Variable reluctance stepper motor can be of single-stack or multi-stack type. Single Stack Variable Reluctance Motor: A variable reluctance stepper motor has salient pole (or tooth) stator and rotor. While rotor has no windings, stator has concentrated coils placed over the stator poles (teeth). Stator winding phase number depends on the connection of stator coils. When the stator phases are excited in a definite sequence from a dc source with the help of semiconductor switches, resultant air-gap field steps around and rotor follows the axis of air-gap field due to reluctance torque developed by the tendency of magnetic circuit …


Updated: May 1, 2020 — 10:35 pm