Types of Steel Rolling Mills: Types of Steel Rolling Mills are either hot rolled or cold rolled. These may be either reversing type or continuous type. The motors used for…
Periodic Intermittent Duty: The class of duty making use of the ability of electric motors to operate with overload is called Periodic Intermittent Duty. The load on the motor is…
Reversible Drive using Field Reversal: A Reversible Drive using Field Reversal can be realised as shown in Figs. 4.83 and 4.84. In Fig. 4.83, the armature is fed from a…
Chopper Fed DC Drives: The variable voltage to the armature of a dc motor for speed control can be obtained from a dc chopper which is a single stage dc…
Synchronous Speed on Variable Frequency Supply: As has already been discussed, the speed of a synchronous motor can be varied by supply frequency variation similar to an induction motor. The…
Speed Control Using Slip Energy Recovery Schemes: The foregoing discussion makes it very clear that the methods of voltage control and rotor resistance control have poor efficiency, particularly at low…
Chopper Controlled Resistance: By interrupting the flow of current through a resistance R in a periodic fashion using a switch, the value of resistance can be effectively varied. The interrupÂtion…
Selection of Ratings of Devices of a Chopper Converter: Chopper Converter - The waveforms of currents and voltages are useful in deciding the ratings of devices. The main thyristor carries…