13-23
TROUBLESHOOTING
SM CKDDCI 2-A.3 GB
13.5.20 Checking for electromagnetic interference (EMC problems)
13.5.20.1
EMC interference to the A/C unit
Locations most susceptible to interference
1) Locations near broadcast stations where there are strong electromagnetic waves.
2) Locations near amateur radio (short wave) stations.
3) Locations near electronic sewing machines and arc-welding machines.
Problem:
1) The unit may stop suddenly during operation.
2) Indicator lamps may flicker
Correction Actions:
The fundamental concept is to make the system less susceptible to noise by Insulation for noise or
distance from the noise source.
1) Use shielded wires.
2) Move unit away from the noise source.
13.5.20.2
EMC interference to near by home appliances
Locations most susceptible to interference:
1) A television or radio is located near the A/C and A/C wiring.
2) The antenna cable for a television or radio is located close to the A/C and A/C wiring.
3) Locations where television and radio signals are weak.
Problem:
1) Noise appears in the television picture, or the picture is distorted.
2) Static occurs in the radio sound.
Correction Actions:
1) Select a separate power source.
2) Keep the A/C and A/C wiring at least 1 meter away from wireless devices and antenna
cables.
3) Change the wireless device’s antenna to a high sensitivity antenna.
4) Change the antenna cable to a BS coaxial cable.
5) Use a noise filter (for the wireless device).
6) Use a signal booster.
