POWERSTAT®Variable Transformers of the 21-22 Series are of open construction and are primarily designed for back-of-panel mounting. The rated output for the 21 Series is 5 amperes for constant current loads and 7 amperes for constant impedance loads.For the 22 Series, the rated output is 2.25 amperes for constant current loads and 3.25 amperes for constant impedance loads. The 21 Series types operate from 120 volt lines and the 22 Series types from 240 volt lines. The tapping arrangement permits an output voltage range of mo to line voltage or zero to 17 percent above line voltage. Voltage drops for loads less than full load are proportional. Driving torque, d-c resistance per coll and maximum core and brush loss when operating under no load are given in the chart.All manually 21 Series operated units have a 3 3/4 inch (95.3mm) dial graduated 0-100 and an angle of rotation or 320·from the zero to maximum output voltage. Adjustable shafts can be extended from either end of the units, permitting general utility mounting if desired. In addition to the conventional screw-type method of connection, terminal adapters supplied with the units can be quickly mounted on the terminals for use with push-on connectors or soldered connections.