Compressor / Pneumatic / Electrical Guru's

IainB · 30 Jun 2007 at 21:58

In my search for new toys, Ive aquired £600 worth of ABAC's finest compressor pump http://www.abac-support.co.uk/Pumps/B6000.htm (yes...its a touch large). I didnt pay £600 - managed to get it FOC

Now a pump of this calibre would turn its nose up at a puny 50L Clarke compressor / receiver, which I have since sold (actually, it would have been too big to fit anyway)

This morning found me doing a small road trip down to see the 'toy' and pick up a S/H receiver.....slightly bigger at 300L and another pump that came with it (note to self - 300L receivers are BIG and cast iron pumps to fill such a best are chuffing heavy) managed to fit it in the Mondy (just)

Anyway - the reason, finally, for this post. The ABAC ideally needs a 7.5hp motor to run it, which would mean 3 phase, as im domestic single phase - the highest I can go is 3HP (or thereabouts) and this is where I get confused. The pump is spec'd to run at 1450RPM, a lot of the single phase motors Ive seen are running higher RPM's so - if I used a small V belt pully on the electric motor - would this give any torque advantage to the motor and hence pump - with the pump still spinning at approx 1450RPM?

L1J · 30 Jun 2007 at 22:24

What sort of power supply do you have available?

You can get single phase 7.5HP (5.5kW) motors that operate at 1450 rpm, off the top of my head that would need about 30A.

I'll make some enquiries for you Monday with my Motors supplier. What sort of space do you have available to mount it?

Overkill comes to mind

IainB · 1 Jul 2007 at 00:12

L1J said:
What sort of power supply do you have available?

Overkill comes to mind

One of my infamous (and stupid) ideas....no replacement for displacement and all that

though I think a 150L receiver would have worked fine! Now its on the garage and we have 'chucked' the old pump on - I am thinking...oops its a bit big!

Im running off a std main - really need to put in a dedicated supply, but its a lot of hassle and not high on my list of things to do at the minute

Will get a picture tomorrow of the space available

IainB · 1 Jul 2007 at 20:53

Pics as promised....

This is the old pump unit (now on E-Bay!) they both must be moving some air - as the inlet into the receiver is err 1 1/4 inches wide :eek:

This is the new ABAC pump in place - as you can see I have a 'little' room to play with for the positioning of the motor

Apologies for the state of the garage - still have to finish building the shed and clearing out my old E30 bits!!

( |-| |2 ][ $ · 1 Jul 2007 at 21:15

Just wondering, what you going to use all that air for? Storing it up for when we all run out?

sigma · 1 Jul 2007 at 21:24

hahaha that's nuts

IainB · 1 Jul 2007 at 21:30

( |-| |2 ][ $ said:
Just wondering, what you going to use all that air for? Storing it up for when we all run out?

I have a couple of tools that eat air, and if I want to spray 2 pack, I can feed my mask and gun without it running out....but...it is a bit bigger than the pics looked before I went to see it!!

And I guess - if I want to sell it on a get something smaller, the current cost to me (£50 minus anything I get for the old pump unit) I can get back when its all up and running - the same size from someone like ABAC are >1K+

L1J · 1 Jul 2007 at 22:13

Can you measure the distance between centres of those slots the motor will mount on?

IainB · 1 Jul 2007 at 22:52

L1J said:
Can you measure the distance between centres of those slots the motor will mount on?

Will explain this as best I can!!
Distance between the 2 elongated slots at its shortest is 10 cms at its longest is 18 cms. Moving onto length ways between the 1st and 2nd is 16 cms and between the 1st and 3rd is 19 cms.

I did notice that the pulley on the pump is approximately 7cms out – so im guessing I need something with a longer shaft and/or more support away from the foot of the motor

Pulley V's are 13mm at the top (didnt get a bottom V measurement) pulley is 43cm's in diameter and the bolt width (for the motor slots is 12mm)

Lopéz · 1 Jul 2007 at 22:53

You mentalist

Can I bring down the Supra to spray it?

L1J on MSN said:
Llyr says:
that compressor will easily spray a car, feed a mask, run a small powerstation at once!

IainB · 1 Jul 2007 at 22:56

Lopéz said:
You mentalist

Can I bring down the Supra to spray it?

Let me get it all working, then feel free - its a bit of an animal isnt it!!

Gadge · 1 Jul 2007 at 23:12

I 'think' i have seen 3 phase motors ran under single phase before today, using a capacitor. Google may shed more light on this.

Adam_151 · 1 Jul 2007 at 23:13

Random thoughts, in no order WRT electrics:

1450rpm, That almost certainly sounds its designed for a 3Ph induction motor with 2 pole pairs per phase, and at 7.5hp and on an air compressor it would probably normally be connected to a star/delta starter, anyway at over 0.37kw it has to have a starter with overloads in (thermal only circuit breakers very closly matched to the motors running current)

Assuming you don't have a 3 phase supply (have you considered getting a quote for one from your local DNO?), those high rpm motors you have seen are probably series wound DC universal motors of the type used in hand held power tools, washing machines etc, not really ideal, but I suppose its not impossible to gear it down and get increased torguw etc, how well it'd work in real world I don't know.

Other options... there are tricks for running a 3 phase induction motor on a single phase, some using another 'pony' motor and some using capacitors etc, none are particualy elegant though (and not sure how torgue is affected) there is a proper way to use a 3 phase induction motor on a single phase tho, that is an appropiate inverter drive* (the marvels of modern electronics being as they are... you can even ramp the frequency up and down to vary the speed... but they are expensive!)

Single phase wise though... its about 30A, now I don't know what size your supply is, or what else you have on it, but thats a big load if its a domestic supply

*If you see an airconsitioner advertised as inverter drive, thats what it means, it can control the speed with an inverter drive, rather then switching on and off to maintain a temperature

L1J · 1 Jul 2007 at 23:47

Adam_151 said:
Random thoughts, in no order WRT electrics:

1450rpm, That almost certainly sounds its designed for a 3Ph induction motor with 2 pole pairs per phase, and at 7.5hp and on an air compressor it would probably normally be connected to a star/delta starter, anyway at over 0.37kw it has to have a starter with overloads in (thermal only circuit breakers very closly matched to the motors running current)

Assuming you don't have a 3 phase supply (have you considered getting a quote for one from your local DNO?), those high rpm motors you have seen are probably series wound DC universal motors of the type used in hand held power tools, washing machines etc, not really ideal, but I suppose its not impossible to gear it down and get increased torguw etc, how well it'd work in real world I don't know.

Other options... there are tricks for running a 3 phase induction motor on a single phase, some using another 'pony' motor and some using capacitors etc, none are particualy elegant though (and not sure how torgue is affected) there is a proper way to use a 3 phase induction motor on a single phase tho, that is an appropiate inverter drive* (the marvels of modern electronics being as they are... you can even ramp the frequency up and down to vary the speed... but they are expensive!)

Single phase wise though... its about 30A, now I don't know what size your supply is, or what else you have on it, but thats a big load if its a domestic supply

You can get a single phase 5.5 kW motor off the shelf! I dont see the point in over complicating things by using inverters etc unless no easier way is available.

Agreed that a control circuit is needed, a Star/Delta starter would be overkill though for such a small motor.

The exisiting supply would have to be chekced to see if its adequate, and upgraded if not. It's not that big a load for a domestic supply, have you seen how much current a 11kW shower draws?

Dogbreath · 2 Jul 2007 at 00:02

L1J said:
You can get a single phase 5.5 kW motor off the shelf! I dont see the point in over complicating things by using inverters etc unless no easier way is available.

Agreed that a control circuit is needed, a Star/Delta starter would be overkill though for such a small motor.?

It would certainly be overkill for a single phase, seeing as star and delta connections are appropriate only for 3 phase.

The bottom line is that if the compressor requires 7.5 HP to get it's rated airflow and pressure, then no amount of messing with pulleys will fix it. You can run it slower to reduce the HP requirement, but obviously airflow will be reduced accordingly.

A 30 Amp single phase supply is possible to have installed in a domestic building, but without this you are stuck with about 3.5hp, which could potnentialy run the compressor at around half speed, with half the airflow.

IainB · 2 Jul 2007 at 00:11

Dogbreath said:
The bottom line is that if the compressor requires 7.5 HP to get it's rated airflow and pressure, then no amount of messing with pulleys will fix it. You can run it slower to reduce the HP requirement, but obviously airflow will be reduced accordingly.

A 30 Amp single phase supply is possible to have installed in a domestic building, but without this you are stuck with about 3.5hp, which could potnentialy run the compressor at around half speed, with half the airflow.

Thanks Dogbreath,
Been having a convo with Llyr over MSN regarding this, normally (pfft! - me - normal) I wouldnt have got a pump that needs this sort of HP, but I defy anyone to turn down a freebie of this type....just want it working better than my 'Clarke use an air tool for 30 seconds then wait for it to catch up again' compressor.

L1J · 2 Jul 2007 at 00:16

Dogbreath said:
It would certainly be overkill for a single phase, seeing as star and delta connections are appropriate only for 3 phase.

You're correct, I was thinking of 3 phase motors at the time!