Blower Noise (fwd)

[prinaldo@mindspring.com]

Chuck,

Sorry, I don't have the answer. I am forwarding this to ARRL Lab Supervisory
Ed Hare, as he and his staff handle these types of RFI problems. Also, I am
circulating it to the AMRAD (tacos) reflector in hopes someone has some advice
for you.

Paul 

-------- Forwarded message --------
Date: Thu, 18 Jul 2002 18:09:10 -0400
From: prinaldo@mindspring.com
Reply-to: 
To: prinaldo@arrl.org
Subject: Blower Noise
 
July 18, 2002

Dear Paul,

Most likely you are a very busy person and have little time to spend on other 

people's problems. However if you are able to steer me in the right direction 

to help me solve mine I will be very grateful.
About two years ago I had a new HVAC unit installed. The blower motor is a 
variable speed General Electric Model #  HD 44AE120. The problem is that 
whenever the motor starts up it produces a noise on my Yaesu FT 101B on 10 
Meters and 20 Meters.
When the blower motor is not running the S-Meter may read approximately 2.5 - 

3.0 units, with the blower motor running the S-Meter may read 7.0 - 8.5 
units. When switched to a dummy load (cantenna) the noise disappears. Switch 
back to the dipole or yagi the noise appears. I have written to the 
manufacturer (Carrier) several times and they have sent the installation crew 

back to 1) change the motor, 2) install Radio Shack Ferrite inductor on the 
AC line feeding the unit 3) install shielded wire to the thermostat 4) ensure 

the unit is properly grounded. All four did not alleviate the problem. 
(Carrier Corporation policy prohibits me from talking to their engineers, I 
must write to the Customer Relations Department.) There are 13 electrical 
leads from the control board to the motor. I have installed a ferrite cable 
type inductor on the leads and experienced no relief. The HVAC is a gas unit 
and the vent protrudes through the roof about three feet, and is 
approximately ten feet from my dipole and twenty feet from my yagi.  I 
disconnected the vent pipe at the furnace and the noise lever rose about two 
units on the S-Meter. I don't know how to contact General Electric Motor 
Division, and I doubt they would let me talk to their engineers for fear of 
liability, as my feeling are that the motor is generating RFI. (I think this 
because I can hear the difference in noise level when the motor speed changes.

Any ideas that you can suggest will be extremely helpful.

Chuck,
        KA4KGH