The Synchronous Converter (Rotary)

Author: E.E. Kimberly

The synchronous converter is a machine which may be used as a synchronous motor and a d-c generator simultaneously. It is essentially a d-c generator with armature taps connected through slip-rings to external terminals. Through these taps the machine may be run from a polyphase line as a synchronous motor. See Fig. 29-4 for the construction of such a machine.

Fig. 29-4. Diagram of 6-Phase Synchronous Converter

In order to produce the usual d-c voltages, such as 230, 250, 550, and 600, it is necessary that the a-c voltages at the slip-rings have special values which are different from those in standard commercial use. For this reason, transformers of special secondary voltages are always supplied as regular equipment with the converter. The following table gives the required ring-to-ring a-c voltages necessary to produce 250 volts d-c at the commutator with 1-, 3-, 4- and 6-phase supply voltages.

Number of Supply Phases	Ring-to-Ring A-C Voltages
1	176.7
2	153
3	125
4	88.5