Electric Motors and Drives, 2nd Edition

254 Electric Motors and Drives

isolated from each other (i.e. the motor cannot be connected in

the conventional star or delta fashion, but must have both ends

of each winding brought out), or each double-converter can be

supplied from separate transformer secondaries.

In practice there are several power-circuit configurations

which can be used with star-connected motors, and which differ

in detail from the set-up described above, but all require the

same number of thyristors to achieve the waveform shown in

Figure 7.9. This waveform is referred to as six-pulse (see

Chapter 2), because the output has six pulses per cycle of the

mains. A wors ...