Have you verified that the noise is being _generated_ by the fan? In some cases, I've found system wiring that was picking up noise from another part of the system, and 'carrying' it to the AC inlet. If this seems plausible in your case, try stalling the fan (momentarily!), or replacing the fan with a resistive load of the same power level.
On Mon, 25 Oct 1999 23:50:10 PDT, "Ray Levasseur" <ray_levass...@hotmail.com> wrote: >I was hoping I could get some suggestions from the group on a conducted >emission problem I am presently working on. I am measuring to the EN 55022 >Class A levels and have a non compliant system air blower. The blower is an >Ametek Windjammer and is used to positively pressurize our product. The >blower is normally used in vacuum cleaners and is probably rarely used in IT >equipment. The blower is inexpensive and the supplier is not too keen to >provide the modifications to meet our requirements. We use the blower in >some of our products either off the line (230 Vac) or through the power >distribution system and the system ac line filter. I have tried the off the >shelf line filters (Corcom, Schaffner, Okaya, Delta and Spectrum Control) >but they all fizzle out below 200 kHz. The blower generates tons of noise >and I am having difficulty passing the levels at 150 kHz. I have tried >various caps across the line and line to ground but can't get the low end >solved. I was wondering if anyone has any experience with this type of >problem or has worked with the Ametek blower? Any suggestions would be >greatly appreciated. > >Ray Levasseur >EMC Compliance >Creo Products -- Patrick Lawler plaw...@west.net --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
