The “HFA: type units are now available as standard items in the differential type construction. The unit is mounted with an un-grounded rotor making it suitable for a wide field of application. In addition to the features of the “HFA” the design also incorporates the use of a spring bronze silver plated wiping contact on the rotor.
The “HFAD” and the “HFBD” double section capacitors are dual balanced rotor units employing front and rear panels plus a single ball rear thrust. Both units are applicable to transmitter design. The construction features are similar to the “HFA” and the “HFA Differential” type capacitors. Additional special feature employed on the “HFBD” type incorporates the use of an insulated shaft extension on the rotor to safeguard against shock hazards with the application of high voltages.
Straight line capacity. Air gaps and test voltages are as indicated in table. However, “HFBD” breakdown voltages are doubled and capacitance values approximately halved when sator sections are connected in series.