Unbalanced Rotor Impedance Operation: Earlier Unbalanced Rotor Impedance Operation were employed for starting and speed control. They are not in use any more. However, a loose contact in the rotor circuit can cause unbalance in…
Unbalanced Source Voltages Operations: As Supply voltage may sometimes become unbalanced, it is useful to know the effect of Unbalanced Source Voltages Operations on motor performance. Further, motor terminal voltage may be unbalanced intentionally for…
Three Phase Induction Motors: Three Phase Induction Motors are of two types: squirrel-case and wound-rotor. In squirrel-cage, the rotor consists of longitudinal conductor-bars shorted by circular connectors at the two ends while in wound-rotor motor,…
Closed Loop Speed Control of DC Motor: Closed Loop Speed Control of DC Motor - The converters (rectifiers and choppers) are built using semiconductor devices, which have very low thermal capacity. Consequently their transient and…
Chopper Control of Series Motor: Motoring : Chopper Control of Series Motor and va and ia waveforms will be same as shown in Fig. 5.41. Va is given by Eq. (5.113). However, e is not constant but…
Chopper Control of Separately Excited DC Motor: Motoring Control : A transistor Chopper Control of Separately Excited DC Motor drive is shown in Fig. 5.41(a). Transistor Tr is operated periodically with period T and remains…
Drawbacks of Rectifier Fed DC Drives: Drawbacks of Rectifier Fed DC Drives are as follows: 1. Distortion of Supply: Source current of a rectifier has harmonics. In a weak ac source, with high internal impedance,…
Rectifier Control of DC Series Motor: Single-phase controlled Rectifier Control of DC Series Motor are employed in traction. A single-phase half-controlled Rectifier Control of DC Series Motor is shown in Fig. 5.37(a). Equivalent circuit of…
Four Quadrant Drive With Field Reversal: Four Quadrant Drive With Field Reversal as shown in Fig. 5.36, armature is fed from a fully-controlled rectifier and the field from a dual converter so that field current…
Dual Converter Control of DC Separately Excited Motor: A Dual Converter Control of DC Separately Excited Motor (Fig. 5.35) consists of two fully-controlled rectifiers connected in anti-parallel across the armature. For power ratings upto around…
