Static Scherbius Drive: The main limitation of the Kraemer drive discussed is the operation at sub-synchronous range due to diode rectifier. Super synchronous speeds can be achieved if the power is fed to the rotor…
Braking and 4 Quadrants Operation: Subsynchronous converter cascades have been used, till now, in applications requiring one quadrant operation. These can be employed for drives where at least one electrical braking is required. A 4…
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 speeds, and find limited application.…
Chopper Resistance in the Rotor Circuit: Speed control by means of slip variation can be achieved by employing a variable resistance Chopper Resistance in the Rotor Circuit. From the equations it is clear that the…
Derating Factor of an Electric Motor Operating on AC Voltage Controller: Typical derating factor of an induction motor fed from a voltage controller are shown in Fig. 4.5(d) when the motor drives a fan or…
3 Phase Induction Motor Construction: A converter fed 3 Phase Induction Motor Construction has the following advantages over a line fed motor: 1.Smooth start up is guaranteed by variable frequency starting from a low 2.Soft…
Control of DC Electric Motor: A separately excited DC Electric Motor is very versatile as a variable speed motor. Its speed can be varied by varying the applied voltage to the armature or field current.…
Three Phase AC Voltage Controller: To control the current and voltage of three phase loads, Three Phase AC Voltage Controller are required. The single phase controller described previously can be introduced singly in each phase…
Cycloconverter: A variable frequency supply for feeding a three phase motor can be obtained from a cycloconverter which operates on a 50 Hz supply and provides a variable frequency supply at the output (Fig. 3.105).…
Harmonic Reduction: The output voltage waveform of an inverter is non-sinusoidal. It contains a rich harmonic content. The Harmonic Reduction cause additional losses and torque pulsations if a three phase motor is used as a…
