There are 4 different electronic modules for the BD series.:
You probably have the standard 101N0210 single speed with the plastic box.
The Danfoss part number for the single speed shielded module is 101N0220.
The 101N0300 is the AEO variable speed with plastic box and the 101N500 is
AEO with shield.

The AEO future saves a bunch of amp hours by adjusting compressor speed to
the load but the single speed models can be hooked to the Frigoboat SSC and
get the same optimization with a slightly better algorithm. They both work
on the principle that the system is most efficient when it runs for long
cycles at the lowest speed but the SSC has an override to run at full speed
for chill down.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"krj" wrote in message
...
Glenn Ashmore wrote:
This has been discussed on Rparts forum a couple of times. The power
unit of the BD series of compressors is a variable frequency inverter and
is notorious for creating RF noise. Danfoss makes an aluminum shielded
model but they are hard to find and don't help with conducted noise. The
digital thermostat is not normally a source.

Some things that will help are ferrite chokes on all wires going to the
power unit to reduce conducted noise. You may have to experiment with
the size to cut the frequencies that you need. Also lining the
compressor locker with metal screening tied to ground reduces radiated
noise.

Glenn,
You are right. It is not the digital thermostat. I disconnected the
thermostat leads from the compressor module and put a jumper between the
terminals to turn on the compressor. The noise is still there. It is being
radiated. I have clamp on ferrites on all the wires to the thermostat,
power leads, etc. Any idea where to purchase the shielded module. The
local marine refrigeration shop didn't seem to know anything about it.
krj