A Simple Electric Motor: Variable speed drives in the industry employ a simple electric motor as their drive motors mainly because they enjoy several specific advantages, such as overload capacity, smooth speed control over a wide range, capability of operating in … (Read More)

Characteristics of DC Motor: DC Motors are of the rotating armature type. The armature winding is a closed winding through the commutator. The armature is supplied through the brushes which are placed along the neutral axis on the commutator. The field … (Read More)

Speed Torque Characteristic of Separately Excited DC Motor: The circuit equation of a Speed Torque Characteristic of Separately Excited DC Motor whose armature, having a total of Z con­ductors, is wound for 2P poles (the brushes divide the winding into 2a … (Read More)

Speed Torque Characteristic DC Shunt Motor: The preceding discussion shows that armature voltage variation gives creeping speeds. The simple rheostatic method provides a Speed Torque Characteristic DC Shunt Motor with little hardness and little stability. Ward Leonard control (smooth variation of … (Read More)

Speed Torque Characteristics of Series Motor: The field winding is connected in series with the armature (Fig. 1.2(b)). The armature current and field current are the same. The operating Speed Torque Characteristics of Series Motor may be deduced for a series … (Read More)

Speed Torque Characteristics of DC Compound Motor: A schematic of a Speed Torque Characteristics of DC Compound Motor is shown in Fig. 1.18. There are both series and shunt fields (separately excited fields). The orientation of the series flux may be … (Read More)

DC Motor Speed Control: In the foregoing sections we discussed the torque-speed characteristics of dc motors, bringing out the effects of armature voltage variation and field current on them. The discussion also applies to the study of the methods of DC … (Read More)

Characteristics of Three Phase Induction Motor: The performance Characteristics of Three Phase Induction Motor can be de­rived using the approximate equivalent circuit shown in Fig. 1.20(a). In the circuit The phasor diagram of the motor is shown in Fig. 1.20(b). In an induction … (Read More)

Torque Speed Characteristics of Induction Motor: From Eq. 1.27 it can be observed that the maximum torque is independent of rotor resistance. However, the slip at which the maximum torque occurs changes with rotor resistance. When the rotor resistance is increased, … (Read More)

Characteristics of Synchronous Motor: Characteristics of Synchronous Motor are constant speed motors. The speed of the motor is decided by the number of poles and frequency. Compared to an induction motor, it is very sensitive to sudden changes of load. This … (Read More)

DC Motor Electric Brakes: While operating electrical drives it is often necessary to stop the motor quickly and also reverse it. In applications like cranes or hoists the torque of the drive motor may have to … (Read More)

Braking of Induction Motor: The three types of Braking of Induction Motor, namely regenerative, dynamic and counter current braking can be accomplished with induction motors also. Regenerative braking When the rotor of an induction motor runs faster than the stator field the slip … (Read More)

Braking of Synchronous Motor: The methods that are employed for Braking of Synchronous Motor are: Regenerative braking while operating on a variable frequency supply Rheostatic braking Plugging Regenerative braking When the motor operates as a variable speed drive motor utilizing a variable frequency supply, it can … (Read More)

Starting Method of Induction Motor: Transient processes involved with the Starting Method of Induction Motor in a variable speed drive require a detailed study. The electric motor and connected load accelerates to the rated speed from rest under the influence of … (Read More)