MIL-DTL-38195D
3.9.3 Governing-system. The governing system shall provide the speed (frequency) performance as specified
herein.
3.9.3.1 Frequency regulation. The system shall provide isochronous operation. For every load change (including
rated load) the frequency regulation shall not exceed 0.25 percent of rated frequency (see 3.10.1; 4.2; 4.3.3; and
4.5.1).
3.9.3.2 Short term stability (30 seconds). At every constant load from no-load to rated load, the system shall
maintain frequency within a bandwidth equal to 0.5 percent of rated frequency (see 4.2 and 4.5.1).
3.9.3.3 Long term stability (4 hours). At constant ambient temperature, constant barometric pressure, constant
voltage and constant load from no-load to rated load, the system shall maintain frequency within a bandwidth equal
to 1 percent of rated frequency in a 4-hour operation period (see 4.2; 4.3.3; and 4.5.1).
3.9.3.4 Transient performance. Following a sudden increase or decrease in load up to and including rated load,
the governing system shall re-establish stable engine operating conditions (see 6.3.5) within 1 second for load
application and 1.5 seconds for load rejection (see 4.2 and 4.5.1).
3.10 Electrical system.
3.10.1 AC generator and exciter. The generator and excitation system (exciter, voltage regulator and other
accessories necessary to control the output voltage) shall meet the requirements in Table II (see 3.4.1).
3.10.2 DC transformer-rectifier. The direct current system shall be of the transformer-rectifier type and shall
meet the requirements as specified in Table III.
3.10.3 Instruments, controls and other devices.
3.10.3.1 Protective devices. Protective devices shall act to open or close the main contactor as specified in
Table IV.
3.11 Pneumatic system. The pneumatic power system shall consist of a load control valve for controlling
compressor bleed air through flexible ducting to an exterior pneumatic servicing connection, and all necessary
controls for regulating loading of the air source. The system shall furnish continuous automatically controlled
pneumatic power, which shall meet the minimum output requirements specified herein (see 3.4.1; 3.5.2; 4.2;
4.4.1.2.5; and 4.5.1).
3.11.1 Load control. The load shall be controlled by the load control valve, which shall open only after the
operating speed range is reached regardless of the position of the load switch. The valve shall have an opening rate
in the range of 3 to 10 seconds and a closing rate of not more than 0.5 seconds. Normal operating pressures shall be
automatically maintained unless manual change of the load switch is selected.
3.11.2 Transient performance. Pressure fluctuations from a suddenly applied load, shall be critically damped
within 5 seconds after valve opening, and shall not exceed ± 3 percent of rated output from the steady-state
condition (± 1 percent of rated output) (see 3.10.1; 4.2; and 4.5.1).
3.11.3 Depressurization. The air delivery hose shall be automatically depressurized to not more than 1 psig in 5
seconds upon closure of the outlet valve.
3.11.4 Protective devices. The engine shall be automatically protected from excessive loading or temperatures
by a regulating load control valve and independent over-temperature limiting control and flow restrictor.
7
For Parts Inquires call Parts Hangar, Inc (727) 493-0744
© Copyright 2015 Integrated Publishing, Inc.
A Service Disabled Veteran Owned Small Business