----- Original Message -----
From: "Ed Briggs" <edbriggs@optonline.net>
To: "AMPS" <amps@contesting.com>
Sent: Sunday, August 15, 2004 4:46 PM
Subject: [Amps] Suggestions to quiet a blower
> A perennial question..
>
> I'm considering trying to quite down the blower in my Al-1200. I am
using the stock EBM G2S085-AA which is a single inlet centrifugal
blower which I run at top speed since it is only a 31 cfm blower at
0". From what I've seen, it is the quietest of it's type, spec'ed at
37 dBA.
>
> I *think* (and that's why I'm soliciting suggestions) that there are
two primary sources of noise in this installation. One is mechanical
vibration, which I'm thinking of one of several approaches:
>
> a) Mount a rubber 'mouse pad' between the fan and the chassis, or
> b) drill out the mounting holes in the chassis, and install rubber
grommets to isolate the mounting screws from the chassis, then RTV or
silicon caulk round the perimeter of the blower mounting flange, or
> c) any better suggestion
>
>
> The second source of noise seems to be a higher pitched noise that I
*guess* is related to the ball bearing and airflow. I imagine that
some sort of a baffle over chassis vents with several inches of
clearance would help. I've seen carboard boxes suggested.
>
> Anyway, if anyone has any good ideas, particuarly regarding the
mechanical isolation of the fan/chassis please let me know
>
> Much obliged for any comments
Hi Ed,
>From my EBM catalogue the model G2S085AA-03 is producing 48dbA at
full speed,
this with ball bearings or sintered sleeve bearings.
At 0" it is delivering 44cfm at full speed of 1950 rpm.
There is another EBM blower, a little bit larger, the model
G2S108-AA03, that runs with 650rpm only at 27dbA. It delivers 35cfm at
0".
My catalogue is quite old, probably from 1988.
I usually use large oversized blowers with my linears and drop the
speed by voltage step-down which keeps noise always low.
73
Peter
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