I certainly can vouch myself for the longevity of the "Oilite" bearings.
In the blower motors of our ex-Air Force 208U-10's these sleeve bearings are
used,
and to date only one single bearing failure has occurred.
The amplifiers have accumulated about 110000 hours of 24/7 operation since late
1988,
and they were far from unused when they were acquired.
73/
Karl-Arne
SM0AOM
----- Original Message -----
From: <G3rzp@aol.com>
To: <k7fm@teleport.com>; <david.kirkby@onetel.net>; <g3sek@ifwtech.co.uk>
Cc: <amps@contesting.com>
Sent: Tuesday, April 26, 2005 11:51 AM
Subject: Re: [Amps] Resistors
>
> In a message dated 25/04/2005 20:50:57 GMT Standard Time, k7fm@teleport.com
> writes:
>
> But they regularly lubricate them. I no longer make slanderous comments
> about sleeve bearings.
>
>
>
> Ball bearings have lower friction for a given load bearing capability, but
> are noisier. For heavy loads (like steam locomotive axle boxes), roller
> bearings (in the small size, needle bearings) are better. But for things
> like small
> fans, an 'oilite' (sintered phosphor bronze) sleeve bearing, well
> impregnated
> with oil, is in my opinion, going to take a hell of a lot of beating,
> because of its lower noise, lower cost and longer life.
>
> Back in 1996, a Boeing 747 - 400 on a BA flight from Johannesburg to London
> was over Abbeville in northern France at about 0630 when a passenger called
> the flight attendant and complained about sparks, smoke and flames coming
> out
> of a ventilation grill by his feet. The cabin crew moved him to another seat
> (!), and called the guys up front. The co pilot shot a fire extinguisher
> through the grill, the Captain declared a Mayday, made an emergency landing
> at
> Heathrow, and the passengers evacuated. The problem turned out to be a ball
> race in the three phase fan of a humidifier, which had seized after only
> 3000 or
> so hours. The situation was was exacerbated because Boeing had managed
> (quite accidentally) to fit a 25 amp breaker to protect wiring rated at 4
> amps,
> instead of a 2.5 amp breaker. Now if aircraft quality bearings can fail that
> soon, what does it say for cheap fan bearings? (Can't remember if it was
> lubrication failure - anyone wanting full details can find them in the AAIB
> accident reports for 1996)
>
> 73
>
> Peter G3RZP
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