The Tachometer Test Set or Tachometer Tester is completely self contained in a lightweight aluminum case, designed for portability. The Tachometer Tester requires only connection to a source of electrical power to place in operation. A variable speed drive pad is provided in accordance with AND 20005 to mount the generators to be tested. The speed of this drive pad may be varied from 0 to 5000 rpm by a panel mounted control knob. A precision speed reference monitors the speed of the unit under test and may be selected to indicate RPM X1, RPM X2, or PERCENT RPM. Internal load banks may be selected to load the generator under test, and, while under load, the phase to phase voltage may be selectively displayed on the panel mounted voltmeter. A standard aircraft tachometer generator is mounted inside the Tachometer Tester and may be used to test tachometer indicators. A selector switch is used to select the speed indicator system and the output to indicators under test, to either the internal master generator or to the generator under test.