Motional EMF of DC Motor When the armature is stationary, no motional e.m.f. is induced in it. But when the rotor turns, the armature conductors cut the radial magnetic flux and an e.m.f. is induced in them. As far as each individual coil on the armature is concerned, an alternating e.m.f. will be induced in […]
Until the 1980s the conventional (brushed) d.c. machine was the automatic choice where speed or torque control is called for, and large numbers remain in service despite a declining market share that reflects the move to inverter-fed induction motors. Applications range from steel rolling mills, railway traction, to a very wide range of industrial drives,
Most commercial servo drives accept PWM and direction signals as input. Also, many servo drives produce a PWM output voltage signal to the load such as a motor coil instead of a linearly variable output voltage. A PWM signal is a square-wave signal of fixed amplitude and frequency, but the width of the on and
A very common application of transistors is to construct drivers to drive motors. One such circuit is the H-bridge driver circuit, which is commonly used to drive motors in both directions. The circuit looks like the letter ‘H’ in circuit schematics, so it is called an H-bridge. An H-bridge circuit is constructed using four switching
The base speed listed on a DC motor’s nameplate is an indication of how fast the motor will run with rated armature voltage and rated load amperes at rated field current. DC motors can be operated below base speed by reducing the amount of voltage applied to the armature and above base speed by reducing
Unlike a brush DC motor, a brushless DC (BLDC) motor, as the name suggests has no brushes. Because there are no brushes, a BLDC motor produces little electrical and acoustic noise, and does not suffer from the wear of brushes and the need to replace them periodically. Thus a BLDC motor is more reliable than
Hi friends, In this article, I am providing you some basic information about Brushless DC motor i.e. BLDC motor. With the help of this information you can easily understand the BLDC motor working principle and operation. The torque-speed characteristics and the flexibility of the dc motor have made it a very attractive choice for applications
The performance of a DC motor can be judged by its characteristics and a motor for any particular application can be selected easily. The performance characteristics of DC motor are: Torque versus armature current (T v/s Ia) Speed versus armature current (N v/s Ia) Torque versus speed (T v/s N) Characteristics of DC Motor While
The speed control of dc series motor can be obtained by using various methods shown in the figure. Following few facts about the DC series motor should be kept in mind while studying DC series motor speed control. The current flowing through the armature and field winding of a DC series motor is same. The
Before discussing the speed control of dc shunt motor, we have to find the factors affecting the speed of a DC motor. The speed equation of a DC motor shows that, N α Eb / φ or N α (V – IaRa)/ φ But the resistance of armature winding is small. Therefore the voltage drops IaRa will be