Figure 2-33.-Tachometer Indicator-Generator Test Set TTU-27/E.
for the tester are on the panel assembly. The two-
TACHOMETER INDICATOR-
speed test pad accommodates either two-pole or four-
GENERATOR TEST SET TTU-27/E
pole tachometer generators for testing. The RPM
counter indicator provides a precision readout of
The TTU-27/E has complete facilities for testing
tachometer generator speed with scales of RPM x 2,
the percent and RPM types of tachometer indicators.
RPM x 1, and PERCENT RPM. The tester uses 115-
You can also use it to test four-pole reciprocating
volt, 400-hertz ac power.
engine tachometer generators and two-pole jet engine
tachometer generators. You can use the tachometer
indicator to make the following tests:
NOTE: Don't try to operate the tachometer
tester until after you make the ground connection of
Test tachometer indicators for
starting
the power lead.
voltage and calibration accuracy
The drive assembly consists of a gearbox and a
Test tachometer generators for starting
master tachometer generator. The gearbox drives the
voltage, calibration accuracy, speed, and
two-speed test pad, which mounts the tachometer
output voltage under load conditions
generator under test. A variable dc drive motor
controls the drive speed of the gearbox. Therefore, the
drive motor controls the drive speed of the master
Test tachometer generators and indicators
tachometer and the tachometer generator under test.
either on or off the aircraft
The RPM indicator assembly is part of the
Figure 2-33 shows a TTU-27/E tester. All the
precision speed indicator. The assembly consists of a
operating controls, switches, and indicators required
two-phase
servomotor,
which
drives
an
