Rotary converter

The basic construction of the rotary converter consists of a DC generator (dynamo) with a set of slip rings tapped into its rotor windings at evenly spaced intervals.

The device can be reversed and DC applied to the field and commutator windings to spin the machine and produce AC power.

Rotary converters soon filled the need to use all the competing electric power delivery systems that cropped up in the 1880s and early 1890s.

[7][8] Most machinery and appliances at that time were operated by DC power, which was provided at the user level by rotary converter substations for residential, commercial and industrial consumption.

Rotary converters provided high current DC power for industrial electrochemical processes such as electroplating.

Steel mills needed large amounts of on-site DC power for their main roll drive motors.

Similarly, paper mills and printing presses required direct current to start and stop their motors in perfect synchronization to prevent tearing the sheet.

[9]: 12  Compared to the rotary converter, the mercury arc and semiconductor rectifiers did not need daily maintenance, manual synchronizing for parallel operation, nor skilled personnel, and they provided clean DC power.

1909 500 kW Westinghouse rotary converter
Wiring schematic for a simplified bipolar-field Gramme-ring single-phase –to– direct-current rotary converter. (In actual use, the converter is drum-wound and uses a multipolar field .) [ 2 ]
Wiring schematic for a simplified two-phase –to–direct-current rotary converter, with the second phase connected at right angles to the first [ 3 ]
Wiring schematic for a simplified three-phase –to–direct-current rotary converter, with the phases separated by 120 degrees on the commutator [ 4 ]
Railroad Rotary Converter from Illinois Railway Museum