I have a 3-phase 230V residential supply. It's divided among 3 groups of MCBs all powering single phase devices.
The problem I'm having is that whenever the air conditioning (single phase) turns on during cold start, for example after a brief power outage, the AV receiver connected to a projector loses its video signal for a few seconds.
What I've tried/verified:
- The AC and AVR/projector are on completely different phases and MCBs. I thought this was supposed to prevent voltage drop but something is still causing interference.
- The electrical and AV cables are routed on the opposite sides of the room to avoid interference.
- The power line for the projector and AC are routed through the same conduit
- The AVR rated for 120V is connected to a step down transformer (220/110V).
Any ideas on how to troubleshoot this?
Forgot to mention the AVR/projector is connected to a double conversion online UPS, without it the issue was much worse as both the audio and video would cut out.
The issue was caused by the long HDMI cable that connects the AVR to the projector. I haven't quite figured out what is causing the interference as the only other cables in its proximity are audio cables going from AVR to speakers. The HDMI cable works fine in normal operation and the interference only happens right after an AC cold start.
Issue has been isolated to EMI caused by the long power line of the AC (antenna effect?). Even though the power and AV cables are routed on the opposite sides of the room, the room itself is quite narrow in width.