Can't determine source of interference from DC motor

[Jontyc]

I've got this nasty treadmill, a PWM controlled PM DC motor taking out my ADSL connection and can't locate which mechanism it's doing it by. Maybe it's multifaceted.

The ADSL modem/router is upstairs and I have a cat 5E cable coming downstairs where I have the PC and treadmill next to each other (a treadmill desk).

All the following scenarios work if the treadmill is off but not when it's on.

o Ethernet cable plugged into PC
o Ethernet cable plugged into router near treadmill powered on same circuit as treadmill, laptop plugged into router.
o Ethernet cable plugged into router, powered by isolated circuit to treadmill

However these scenarios don't take out the ADSL:

o Ethernet cable plugged into laptop on battery.
o Ethernet cable left floating, not plugged into anything.

I can only conclude so far that there's so much EMI that it's just radiating into the router, going back up to the modem and flooding its bandwidth. Although the cable coming downstairs is a good 10 yards long, the one from the router to the laptop is only 3 feet.

I've lined the treadmill's motor cover with aluminum foil and earthed it but I'm really clutching at straws here.

And with the first test above, I'm thinking the PC also either gets drenched with EMI or noise is entering from mains contamination, being on the same circuit as the treadmill (albeit supposedly protected from cross contamination by a $150 home theatre power filter board).

Any suggestions what could be going on?

 

[mvs sarma]

Try to have the power supply to treadmill, through emi filter. if possible, bring separate cable to power teadmill from mains input location. Keep CAT5 (6) cable away from mains parallelism by atleast three feet.

 

[Jontyc]

I had tried powering the PC from a different sub-main, but no improvement. I would have thought it all connects back at the main board anyway and wouldn't make a difference.

The cat 5 cable is runs in the same direction as the mains for about 3 yards, but is hanging loosely, averaging about 3-4 feet from it. The ADSL works fine when the cat 5 cable is connected to a laptop, just not the PC or router.