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Re: [Amps] Centrifugal Blowers

To: <>
Subject: Re: [Amps] Centrifugal Blowers
From: "Peter Voelpel" <>
Date: Thu, 27 Jan 2022 23:32:32 +0100
List-post: <>
For my as well.

G2E085 is the EBM blower model for the 3CX1500A7.
G2E120 for 3CX3000A7.

Bought my first G2E085 in 1976 for a 4CX1000 amp, price went up by factor 10
since then.

I think W8JI sells them in his store at reasonable prices. 

Peter; DJ7WW

-----Original Message-----
From: Amps [] On Behalf Of Jim Klein
Sent: Donnerstag, 27. Januar 2022 22:19
To: jim.thom
Subject: Re: [Amps] Centrifugal Blowers

EBM is the only choice for my projects...73 all...K7RDX..

On 1/27/22, jim.thom <> wrote:
> From: Byron Tatum <>
> To: Amps Group <>
> Subject: [Amps] Centrifugal Blowers
> Message-ID: <>
> Content-Type: text/plain; charset=UTF-8
> Hello-? ?Anyone in our group have knowledge of replacing the motor on a
> centrifugal cooling blower? I have been rebuilding a few RF decks made in
> the 1970's by Scientific Radio for the SR-416A transmitter. These RF decks
> are a copy of the Eimac W6PO 144 Mhz design using 8877 tube. They use a
> Kooltronics blower with 5" wheel and square outlet with mounting hole
> centers 2-5/8" apart in a square pattern. I have bearing noise and
> vibration in a few of my motors. The motors are sealed bearing Kooltronic
> #7162-082 type U62, 115 VAC @ 1.55 amp, using 4 ufd capacitor. 2850 RPM at
> 50 Hz, 3400 RPM at 60 Hz.? ? After looking at prices of replacement
> blowers/motors I was shocked. Can I replace the bearings in these motors?
> Or just buy new motors somewhere? I really do not need the performance of
> these blowers, the transmitters were running at 1 KW 24/7 and I am just
> doing SSB/CW. Sure could stand to reduce the blower noise some.?
> ?Thanks,Byron W5FH?
> ##  Phone / contact  Kooltronics and ask them if the bearings can be
> replaced..and if they stock them.  I believe a special bearing tool is
> required to remove / install them.   They might also be able to replace em
> for you.  They are nice folks to deal with on the phone.   German
> EBM-Papst blowers, like what's used on the Ameritron amps, indeed, have
> replaceable does the old  Rotron  CX-33, used on many FM
> broadcast stations.  The CX-33 is still rebuildable, even though out of
> production for years.
> I had several CX-33 blowers, with the cap start, these were 230 vac single
> phase types..and tried them on my small 0-240 vac @  5 amp variac.  Worked
> superb.  I could dial it up anywhere from a crawl to full bore..and
> everything in between.  Then ran em for extended intermediate
> speeds, with no degradation, or heating etc.  A metal finned resistor can
> also be used to slow em down.
> Dayton blowers have a huge catalog online.  They revamped their blower
> up a few years ago, and the new versions all have ball bearings, no sleeve
> bearings..and the new style / design motors only draw  1/2 as much
> Available in flanged or unflanged.   Detailed dimensions, including
> etc, etc, online.
> I bought 4 of the ebm papst replace the oem drake blowers, in
> my 4 x L4B's.  These are the same ones used in the ameritron  AL-1500
> amp.  On that ameritron amp, they offer 3 x speeds, by changing taps.  IE:
> 3 x different voltages fed to the  120 vac blower.   Max speed, and 2 x
> slower speeds.   Max speed used for RTTY / FM. Lower 2 are for ssb / cw
> etc.
> I bought mine from Digikey. Mouser also sells em. The Baffling part is...
> the 230 vac version is one helluva lot cheaper than the 115 vac version,
> like almost 1/2 price, go figure. I never run the drake amps on 115 vac,
> it's a moot point.
> I have seen too many blowers getting tossed... simply from a bad bearing.
> A freq drive will also work to slow em down.  Chinese variable freq drives
> are cheap..and actually work good.
> I also use ebm papst  deluxe  EC ( electronic commutator)   115 vac
> version  blowers.  With a 10 k pot wired in, the speed can be changed from
> 1/2  rpm, to max rpm.  These are  70 cfm @  1.2"  high pressure types,
> on 3CX-3000A7 tubes.  It also has a tachometer output, and bearings are
> field replaceable.  Beauty of the EC motors is... they draw a miniscule
> amount of current, like just .4 amp on high speed...and only .12 amp on
> speed.  Don't even  run luke warm.
> Jim   VE7RF
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