TB 1-4920-443-35
Table 53-11
Voltage Output:
20000 RPM = 10V
0 RPM = -10V (i.e. 0V = 10000 RPM)
Voltage Scaling:
(1/4096) x 20V = 4.9mV (voltage steps with 10V output)
Therefore, scale factor = (4.9mV) / (4.9 RPM) = 1 mV/RPM
Current Output:
20000 RPM = 20mA
0 RPM = 4mA
Current Scaling:
(1/4096) x (20 4mA) = (1/4096) x 16mA = 3.9A (current steps)
Therefore, scale factor = (3.9A) / (4.9 RPM) = 0.8A/RPM
(4) Use the F4/F5 keys to skip from parameter to parameter. Press the F1 key to edit the parameter
currently on the display. Use the F4/F5 keys to move the cursor. The backspace key does not need to
be "shifted". When satisfied with the value, press the ENTER key to store this value. Press ESC if you
wish to discard the input; the previous value will be displayed. Press F3 to return to MENU-A.
(5) The analog output parameters correspond to the limits of the analog output. "Speed Max" for instance
corresponds with +10V out (maximum analog voltage output). "Speed Min" will correspond to -10V
out. The current outputs respond similarly. "Speed Min" will correspond to 4mA, while "Speed Max"
will correspond to 20mA.
54. T55 Electric Torque System
a. Performance Check
(1) Connect the T55 Flight Harness, 20090776-1, to connector J655 of the J-box.
(2) Torque meter zeroing procedure (T55 engine must be installed)
(b) Turn 400 Hz power on.
(c) Remove analogic gage and adjust zero with potentiometer on rear of gage.
(d) Turn 400 Hz power off.
(e) Remove shorting cable and reconnect engine cable to torque meter on engine.
b. Torque meter Indicator Check
(1) Access the connector that mates to the engine on cable 20090776-1.
(2) Jumper pins "Z" and "a" together, and connect to the negative terminal of the millivolt source.
(3) Ensure that the Torque Power switch on the T55 Indicator panel is off.
(4) Connect pin Y of the engine mating connector of cable 20090776-1 to the positive terminal of the
millivolt source.
(5) Set the millivolt source to the following levels and note the response of the Torque meter Indicator on
the T55 Indicator panel. Record results.
Table 54-1Torque meter Indications
Millivolt Source
Indication (5%)
230 6mV (50%)
325 6mV (70%)
430 mV (100%)
