[Amps] Centrifugal Blowers

[Joe Subich, W4TV]

On 2022-01-27 1:34 PM, Roger - W7TZ wrote:

> I put the blower in a sealed box with one side filtered and located
> in the attic and brought the hose out of the ceiling to my rack 
> mounted rf decks for v/uhf.

Be careful with the "remote blowers".  The length of hose/duct adds
to the back pressure the blower needs to accommodate.  If using a
"remote blower," particularly one with added housings/filters, always
check the airflow through the tube and monitor the outlet temperature.

Keep the outlet temperature low enough to provide plenty of safety
factor for the tube seals.

73,

    ... Joe, W4TV


On 2022-01-27 1:34 PM, Roger - W7TZ wrote:
> I use an RV Sewer Kit plus a square flange interconnect and quick
> disconnect. I put the blower in a sealed box with one side filtered and
> located in the attic and brought the hose out of the ceiling to my rack
> mounted rf decks for v/uhf.
> 
> 73, Roger
> W7TZ
> CN83ia
> 
> 
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> On Thu, Jan 27, 2022 at 4:23 AM Rob Atkinson <ranchorobbo at gmail.com> wrote:
> 
>> First, thanks to Paul W9AC and John K5PRO for their accounts.  I
>> worked at a FM near Memphis about the same time that was also a 3 KW
>> with 3 rototillers at 300 feet fed with pressurized heliax.  That must
>> have been a standard configuration FCC licensed for small markets.  I
>> don't remember the tube but our rig was a Harris and someone had
>> placed a box fan laying flat on top of the cabinet and I was told the
>> idea was to help pull air up out of the rig.
>>
>> New blowers have gotten expensive, what a surprise, and I've managed
>> to get by so far with some hamfest finds.  I think there are some
>> cheap ones sold on-line from China but as with tubes, I don't know
>> about the quality.  But I wouldn't be surprised if Daytons are no
>> longer made in Dayton, hi.  I am using a large blower removed from a
>> Sparta 701 AM broadcast rig that was wound to run on 230 v. but I've
>> put 120 across it which slows it down and quiets it.  One set of
>> bearings is shot because it only runs smoothly when resting on its
>> side with the motor facing up.  It's big enough so that on 120 v. it
>> still pushes plenty of air for a single 4-1000 using the black plastic
>> socket.  It rests on an upside down plastic paint bucket with the
>> bottom cut out and holes cut in the side of the bucket so air comes in
>> and up through the wheel and out.  Like the other fellow, who remoted
>> his blower, I am using flexible vinyl dryer duct to the rig.  The
>> blower outlet is a square flange.  I went to a hardware store and
>> purchased aluminum gutter sections that have the drain collar that a
>> downspout can push on to.  I cut out the collar with enough gutter
>> aluminum sheet to make a square around the collar, and punched bolt
>> holes in the corners that lined up with the bolt holes on the blower
>> flange.  Using silicone sealant I bolted the collar onto the flange,
>> giving me something to jam the dryer duct over and fasten with a hose
>> clamp.  I used the same method on the RF PA chassis also.
>>
>> 73
>> Rob
>> K5UJ