Which parts

[stewart.d.campbell]

So have i got this right, i need a motor of at least 8hp, a keyway shaft on it to mount a pulley and a pressure unloader valve to vent the excess pressure when it reaches working pressure.If i have got that right the only thing i am unsure of is how the gearing to the pump would work for the shaft speed of the engine and how to work out what size pulley i need.

 

[eil]

Cant you go on the sip site to find your compressor and compare.
http://www.sipuk.co.uk/tools/air_compressor.html

 

[stewart.d.campbell]

I have and i think this is the sort of setup i would be looking to reproduce.I notice that the motor and pump are on different sides than what i have now with the electric motor.
http://www.sipuk.co.uk/tools/info_SIP04456.html

 

[eil]

You want to keep the heat of the exhaust from the engine away from the inlet to the comp.

 

[stewart.d.campbell]

That is an engine for a generator. So, it has a tapered shaft. Will probably hard to find a pulley for it.

Can the shafts be changed.

 

[eil]

Shaft on an old gen set I had is part of the crank, unless you know someone that can make you up a tapered pulley. Someone posted up a site that you can get different pulleys up on the site a while ago but cant remember offhand.

 

[stewart.d.campbell]

What about this one, is the shaft right on this one?
http://cgi.ebay.co.uk/Briggs-Stratt...m35a32e5d1f&_trksid=p3286.c0.m14#ht_500wt_975

 

[Bsmith]

Hello Stuart,

I don't expect there is any difference between the pressure switches.
But how can you run with a 3 h.p. motor when the original was 5.5 h.p.. It surely won't develop the pressure or you will be plauged with the small motor tripping?

Alec

My compressor used to have a single phase 5hp motor on it, but it used so much power that it dimmed my neighbours lights and mine on start up so I came up with this wainbrave. The 5hp motor ran at 1420rpm, so I bought a new 3hp motor which runs at 2800rpm and instead of the 6" V pulley which was on the 5hp I made a 2.75" V pulley on my lathe for the 3hp motor and installed it. The pump does run a little slower than it did before but its negligible. For the motor to start, especially under load, it needed to be a high starting torque motor which are available on ebay. It needs at least a 15 to 20 amp power supply. Hmm, by the way my 5hp Brooke Crompton motor is for sale (hint). Good luck, Brian (",).

 

[stewart.d.campbell]

My compressor used to have a single phase 5hp motor on it, but it used so much power that it dimmed my neighbours lights and mine on start up so I came up with this wainbrave. The 5hp motor ran at 1420rpm, so I bought a new 3hp motor which runs at 2800rpm and instead of the 6" V pulley which was on the 5hp I made a 2.75" V pulley on my lathe for the 3hp motor and installed it. The pump does run a little slower than it did before but its negligible. For the motor to start, especially under load, it needed to be a high starting torque motor which are available on ebay. It needs at least a 15 to 20 amp power supply. Hmm, by the way my 5hp Brooke Crompton motor is for sale (hint). Good luck, Brian (",).

How much do you want for it, is this the 5hp single phase motor you are talking about?, and also does anyone know what shaft the honda engines on sip compressors have as i have worked out i need a 8hp engine and was thinking i could then just buy the parts that would be on the 8hp petrol compressor.

 

[Bsmith]

Yes it is the 5hp motor but sorry someone else has bought it.

 

[stewart.d.campbell]

Oh well, you have got me thinking about a 5hp electric motor though.Found a few on ebay.What would i need to make this setup work just a motor and a 20amp supply, how do you go about this?

 

[Bsmith]

Oh well, you have got me thinking about a 5hp electric motor though.Found a few on ebay.What would i need to make this setup work just a motor and a 20amp supply, how do you go about this?

The 3hp motor I run now is on a 20 amp supply. I think a 5hp motor would need a 30 amp supply and a start switch which acts like a relay or solenoid. Best to get a sparks advice. Brian (",).

 

[shenion]

My 5HP is on a 20A supply (fast-trip breaker) and runs with no problems. 30A seems like way more than needed.

 

[Bsmith]

So have i got this right, i need a motor of at least 8hp, a keyway shaft on it to mount a pulley and a pressure unloader valve to vent the excess pressure when it reaches working pressure.If i have got that right the only thing i am unsure of is how the gearing to the pump would work for the shaft speed of the engine and how to work out what size pulley i need.

Pulley size is actually very simple to work out Stuart. I'll show you how to do this if you can tell me, the rpm the compressor pump should run at, the diameter size of the the pulley on the pump and the engine rpm. Best wishes, Brian (",).

 

[Bsmith]

My 5HP is on a 20A supply (fast-trip breaker) and runs with no problems. 30A seems like way more than needed.

Yep ok fine that it runs ok with a 20A supply. I say 30A because of a 5hp motor would need a minimum of 15.5 amp or 3730 watt supply to run without any load and you still got to add on the start capacitor, I dont know what amps the start capacitor needs. Brian (",).

 

[Nebula]

If you end up going down the petrol engine route these are well worth a look.
http://www.pump.co.uk/shop/EnginesPetrol&Diesel/LoncinQshaftParalellRecoilStart/d31/sd125

 

[brightspark]

hi there if u are thinking of using a static converter there not realy suitable for starting compressors off .as the restart under load is 2.great if u use a smaller motor single phase check the full load amps on motor plate then try and borrow a clamp on ammeter and check it under load and make sure it doesnt exceed the motor rating amperage