Compressor output.

[HSGB]

Hello,

I don't suppose anyone knows how to work out the output of a compressor? I have aa old Tecalemit Type 212 Compressor, which runs off a 3hp Higgs Motor, which runs at 1430rpm. The diameter of the motor pulley is 6 1/2", and the compressor flywheel is 18" that is a step down ratio of roughly a third. So, I presume the compressor will have an rpm of around 475.

The compressor has two pistons, both on an 80mm stroke with one being 110mm diameter and the other being 50mm diameter. Both are connected via the same crankshaft and do one full stroke 180 degrees apart on each flywheel rotation.

Oh, the compressor has a rating of 200psi, whilst the tank is 150psi SWP, and holds 5.8CF which is 36 gallons or 165 litres.

Anyone know how many CFM's this thing will push?

Thank you.

 

[rtbcomp]

Ask Tecalemit, I understand they're quite helpful.

 

[brightspark]

i dont know the cfm but its a twin stage compresor one larger piston than the other .the larger piston compreses the air into the smaller cylinder then that pumps into the main tank . there more eficient than just an ordinary twin comp with equal pistons and can use a smaller motor to drive them

 

[tigler]

Are you sure the motor is only 3HP ? Seems small for such a big pump. Rule of thumb for smaller compressors is 2 CFM per horsepower, which would make yours 6 CFM !

 

[the snooper]

mine is 14 cfm 3hp motor

 

[brightspark]

just use some airtools on it and see how long it takes to peter out thats all i ever did and still do . one of my comps is 14cfm and has 3hp motor on as well

 

[tigler]

14 cfm fad ?

 

[the snooper]

thats still 9 to 10 cfm not your 6

 

[tigler]

Well it is a rule of thumb and is a realistic guide rather than a manufacturers claim.

 

[the snooper]

my 14 cfm just manages to run an air fed mask and a gun at the same time but only just so that alone says more the 6 cfm

 

[brightspark]

Well it is a rule of thumb and is a realistic guide rather than a manufacturers claim.

my pump is off a comercial vehicle used on air brakes . they tend to be acurate with there output not like mickey mouse compresor sellers , it runs fine on the 3hp motor but struggles with a 2hp

 

[HSGB]

Well you see, I was going to buy a spraygun, but they all have different CFM consumption, so I don't know what mine will be able to cope with.

Tigler, why do you think it is big?

 

[tigler]

HSGB,
I had an Ingersoll Rand with a dual stage V twin pump about that size, but it was driven from a 10 HP motor !

 

[graffian]

The numbers you give, give a 13.9CFM.

 

[HSGB]

This is another thing I don't understand, What difference does the motor size make? At the moment my motor pulley is 1/3 the size of the flywheel on the compressor. If I make the motor pulley only 1/2 the size of the compressor flywheel, I can gain 250rpm just like that!! Just by changing the gearing between the motor and flywheel.

It is all so confusing.

 

[HSGB]

Here is a piccy:

 

[tigler]

The numbers you give, give a 13.9CFM.

Yes, but that rule of thumb applies to small compressors of the hobby type.
Nothings simple !

 

[graffian]

If you were to made that sort of change[to 19CFM] you would probably find you need a 5hp motor.

 

[tigler]

This is another thing I don't understand, What difference does the motor size make? At the moment my motor pulley is 1/3 the size of the flywheel on the compressor. If I make the motor pulley only 1/2 the size of the compressor flywheel, I can gain 250rpm just like that!! Just by changing the gearing between the motor and flywheel.

It is all so confusing.

Not quite. You also change the gearing, you gain rotational speed but it needs more effort to turn.
Think about riding a bike, you change up a gear and go faster but it needs more effort.

 

[graffian]

Yes, but that rule of thumb applies to small compressors of the hobby type.
Nothings simple !

why doesn't it apply to all piston compressors?