Bruce L. Bergman wrote:
On Fri, 17 Jun 2005 19:33:31 +0000 (UTC), Christopher Tidy
wrote:


Just another quick question. On the Bristol compressor I spotted on eBay
I see a pipe leading from the crankcase to the cylinder.

http://cgi.ebay.co.uk/ws/eBayISAPI.d...tem=7980508669

Anyone know what this is for? Is it for pressure lubrication or does it
mean the compressor is double-acting? Just curious.


No, that looks like a single-stage compressor. The line might be a
simple gear pump to squirt oil up under the piston skirt, or it might
be for a centrifugal unloader. When the motor gets up to speed and
the oil pressure comes up in the compressor, the oil pressure allows
the intake valve to close and then it starts pumping.

One post up in the thread, Christopher wrote:


I think unfortunately 7 hp is pushing it from our single phase supply.
At the absolute maximum we can get 230 V 45 A. I know this is about 10
kW but I suspect the motor will overload the supply when starting. My 5
kW welding set makes the lights go dim in the house.


A 240V single-phase 45A service in the UK would translate to a bit
smaller than the USA small residence service for a old house, where
you get 120/240V at 50 to 70 amps or so. Definitely NOT enough to run
any sort of home shop equipment from at the same time there are
residence-type loads being run.

To clarify, the 45 A supply is for the workshop only. However, the 45 A
is drawn from a 100 A supply in the house.

Best wishes,

Chris