Category: Characteristics of Electric Motors

Starting Method of Induction Motor

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 the starting torque. The transient operation during is satisfactory if a sufficiently good starting […]

Braking of Synchronous Motor

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 be regeneratively braked and all the K.E. returned to […]

Braking of Induction Motor

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 becomes negative and the machine generates power. Therefore, whenever the motor has […]

DC Motor Electric Brakes

DC Motor Electric Brakes: 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 be controlled so that the load does not have any undesir­able acceleration, e.g. in […]

Characteristics of Synchronous Motor

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 causes a hunting of the rotor and finally leads to stability problems. It has […]

Torque Speed Characteristics of Induction Motor

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, so is the slip for maximum torque, and the stable operating slip range of […]

Characteristics of Three Phase Induction Motor

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 motor the power transferred to the rotor (Pd), rotor copper loss (Pcu2) and […]

DC Motor Speed Control

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 Motor Speed Control, which may be summarised as follows: Variation of armature voltage by […]

Speed Torque Characteristics of Series Motor

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 motor in the same way as described before for shunt motor/separately excited motor using […]