2nd hand compressor - any info?

Sutty

Recently bought myself a 2nd hand compressor and wondered if anyone had any info about it. Its made by Bristol Pneumatics in 1982, plate on the compressor says model 4S16-50.
Should be an interesting project to get it working, 1st thing I need is an engine as it came with a big 3 phase motor and I only have single phase.

If anyone can help/advise I'd be grateful.

Neil

Skipbreather

Hi Neil-

One alternative to buying a new motor/ engine (provided the original motor works OK) is a phase converter. If you are not familiar with them, they make 3 phase power out of single phase and come in both solid state and mechanical varieties. Biggest caveat is to choose one the correct size/ power range.

Just an example: http://www.use-enco.com/CGI/INSRIT?P...&PARTPG=INLMK3

Do not forget to consider the total cost of the conversion. Depending on what controls/ switches/ etc the unit already has installed, finding a way to feed it three phase might be the cheapest way to go.

Good luck

Ken

Andy

how big is the motor? KW i converted my compressor from a 5.5kw 3phase to run on a 3kw single phase and it works fine.I have to run it from a 20amp supply

andy

abowie

Get 3 phase.

It costs a bit but then you can buy all sorts of fun machine shop toys like big-ass welders and you could build some really cool toroidal spark generators too!

You know you want to. Well I do anyway.

__________________
Andrew Bowie

Rebreather-friendly Buddy

Sutty

I'd love to get three phase but installing it would be prohibitively expensive. A phase convertor sounds great until you realise its an 11KW motor! So a convertor is also expensive and would draw too much current for my domestic supply. Internal combustion seems the only way to go.

iain-hsm

The Bristol 4S16-50 block in 1983 would have cost you £2165-00 new. You don’t list the build model number but something like BP12M-50 or 12BAS-50 sounds something approaching correct. The 4S-16 ran at 700 RPM or 800RPM and required 15HP or 11Kw of power. At the same speed but reducing the output pressure to 275 barg max would also reduce the power required to 10HP or 7.5Kw. The phase converter idea won’t work and you loose 20% to 30% capacity of the motor.

The Yanmar L100 diesel engine although short for the job would just about be the nearest cheapest motor to have a look at. Or a new surplus Lister Petter AC2 at 12 HP would be ideal. Cost about £800 with 24 volt starter, fuel cut off, intake filter but no fuel lift pump. I guess this compressor block would be better suited in a fire station or possible dive shop.

For home use in the UK 4HP 3Kw is about max on 240 volt 50Hz domestic supply wired up like a cooker or shower unit. This limits you around 6 CFM 160 l/min at 350 barg but at least its single phase. Again UK to work on a domestic 13 amp ring main (or plug) you have to draw less than 13 amps single phase domestic you are limited to around 3HP max or about 3 CFM.

On the second hand Bristol block look out for the following:
1. The filter towers and moisture separators were made from HE30 TF alloy and had a life rating of 15 years. If you don’t have plug and ring gauges take out the filter 0-ring at the base fit back the tower less the 0-ring and check how much the tower rocks from side to side!! As the filter shells and separator towers are 23 years old you should change them. Cost around £285 each. Also check the block oil type. Around this time 1983 the oil was changed to Anderol 500 a synthetic diester. Plenty of trouble in store if the original owner did a straight swap from mineral oil. Also check the RPM of the block, as this is splash lubricated it needs the correct RPM Do not under run or confuse the RPM of the block with the over driven fan. Iain

Sutty

Thanks Iain, that is excellent info, have some green.

KENT TOOLING

Scutty

I have a Bristol 10cfm 3 phase compressor that runs of a phase convertor as i do not have 3 phase on my property, i think my convertor cost around £800.00 but i can run other machines including lathes, grinders on it

if you require any further information regarding this machine you can contact me on 01227 700015.

John

__________________
John Perrin
+44 01227 700015
(Technical Director)
KENT TOOLING (Diving Products)
www.divingproducts.co.uk

Fire & Smoke Damper Manufactures
+44 01227 700015
www.tri-prodanpers.co.uk

PeteS

Hmmm, not quite true.

3kW is all you can draw from a 13 amp socket.

16 amps can be drawn from a BS4343 outlet.

And modern shower and cooker outlets are wired for 45 or 50 amps.

So you could draw up to 12 kw from a single point, given a dedicated circuit. But that is a monster motor for single phase. So get three phase installed or use an inverter for single to 3 phase conversion, with a soft start to limit current draw on start up.

__________________
Pete S.

http://www.steggle.co.nz

Every silver lining has a cloud

Andy

my compressor is 14 cfm and i run that of a single phase supply with no probs it does run slower than it should as i used a smaller pully but im only filling dill bottles but it will fill one in about 3 mins


andy