trig TMA44, Руководство по установке

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TMA44 Audio Panel Installation Manual 7 November 2017
01849-00 Issue AB
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Page 10 Trig Avionics Limited
5.3 Cable Harness Wiring
Refer to Appendix C for assembling the wiring harness as required for the
installation. All wires must be MIL-SPEC in accordance with current
regulations. Two- and three-conductor with shield wire must be used where
indicated, and be MIL-C-27500 or equivalent specification. Proper stripping,
shielding and soldering technique must be used at all times. It is imperative
that correct wire be used.
Refer to FAA Advisory Circular 43.13-2B for more information. Failure to use
correct techniques may result in improper operation, electrical noise or unit
failure. Damage caused by improper installation will void the Trig warranty.
5.3.1 Noise
Due to the variety and the high power of radio equipment often found in
today's general aviation aircraft, there is a potential for both radiated and
conducted noise interference.
The TMA44 power supply is specifically designed to reduce conducted
electrical noise on the aircraft power bus by at least 50dB. Although this is a
large amount of attenuation, it may not eliminate all noise, particularly if the
amplitude of noise is very high. There must be at least 13.8 VDC present at the
bottom connector, pin 43, of the TMA44 for the power supply to work in its
designed regulation. Otherwise, it cannot adequately attenuate power line
noise. Shielding can reduce or prevent radiated noise such as beacons, electric
gyros, or switching power supplies, but installation combinations can occur
where interference is possible. The TMA44 is designed in a RFI hardened
chassis and has internal Electromagnetic Interference (EMI) filters on all
inputs and outputs.
Ground loop noise occurs when there are two or more ground paths for the
same signal, such as the airframe and a ground return wire. Large cyclic loads
such as strobes or inverters can inject noise signals onto the airframe that are
detected by the audio system. Follow the wiring diagram very carefully to help
ensure a minimum of ground loop potential. Use only MIL-SPEC shielded
wires (MIL-C-275000, or better). Under no circumstances combine a
microphone and headphone wiring into the same shielded bundle. Always use