Converters for Electric Motors

Two Quadrant Chopper

Two Quadrant Chopper: Sometimes a chopper may be required to provide a two quadrant operation by retaining the current direction in both motoring and braking modes. Such a Two Quadrant Chopper is shown in Fig. 3.86, and its waveforms in Fig. 3.87. The chopper permits a change in the polarity of terminal voltage keeping the

Two Quadrant Chopper Read More »

Regenerative Braking

Regenerative Braking: Sometimes the energy of the load may have to be fed to the supply system. A Chopper in this mode is called regenerative. The chopper working as a switch is connected across the load, which is normally a dc machine and the diode is connected in the line. The dc machine works as

Regenerative Braking Read More »

Chopper Circuit with Input Inductance

Chopper Circuit with Input Inductance: The preceding discussion of the chopper assumes ideal conditions and does not consider the effects of inductances in series with the thyristors. With choppers of large power, the leads connecting the Chopper Circuit to the supply have a definite amount of inductance (Le). Also, reactors are placed in series with

Chopper Circuit with Input Inductance Read More »

DC Chopper

DC Chopper: DC Chopper are mainly dc to dc single stage conversion devices which provide a variable voltage on the load side when fed from a constant dc voltage source. The commutation of the current from the thyristors cannot be achieved by means of supply voltage. The necessary reactive power for the converter must be

DC Chopper Read More »

Four Quadrants Converters

Four Quadrants Converters: Four Quadrants Converters – The converters described in the previous sections are suitable either for one quadrant or two quadrant operation. In the former case stepless speed control is possible by changing the applied voltage. There is no regeneration. In the latter case both speed control and regeneration are possible. The converter

Four Quadrants Converters Read More »

Sequence control of Converters

Sequence control of Converters: Sequence control of Converters – We have shown that fully controlled converters take lagging reactive power from the mains. This requirement is less in half controlled converters and converters with a freewheeling diode, which however do not provide the process of inversion. In both cases the reactive power requirement increases as

Sequence control of Converters Read More »

Scroll to Top