Vacuum motor questions

[AshleyMckendree]

1. Why are 3 stage vacs so much better than 2 stage? On paper 2 Stage usually shows more CFM/h2o Lift


2. What exactly are "Air Watts"? And why cant I find the actual wattage specifications on most 3 stage vacs?

 

[Larry Cobb]

Ashley;

Air Watts is the preferred method of measuring vac POWER.

Lamb uses it for all their vac motors.

The hi-perf Lamb 3-stage #116765 has 485 air watts.

The new Lamb 2-stage with a trick tapered fan has 600 air watts with the same power input.
It also has more CFM (124 max) throughout the operating range.

Larry

 

[Greenie]

Not to lean on Larry, but for every air watts supporter there is a central vacuum guru that will say air watts are bunk, and a term used by salesmen, and you should just look at the performance chart where flow and waterlift cross and balance that against the amp draw of the motor you are looking at.

A 150 cfm motor doesn't do you much good if it's only 50 cfm under load.

 

[Ron Werner]

SO what is the best way, parallel or series, for 2 of those tricked out 2-stage Lambs, to give better performance at the end of a wand, at say 50' of 2" hose?

 

[AshleyMckendree]

Not to lean on Larry, but for every air watts supporter there is a central vacuum guru that will say air watts are bunk, and a term used by salesmen, and you should just look at the performance chart where flow and waterlift cross and balance that against the amp draw of the motor you are looking at.

A 150 cfm motor doesn't do you much good if it's only 50 cfm under load.

Where can I find a good performance chart on some of these motors listing "CFM under load"?

Thank you Larry, and Jeff BTW.

 

[Larry Cobb]

Ashley;

Here is a simplified chart which shows a single hi-perf 3-stage vac, along with one & two 2-stage vacs (two in parallel). A CMP 14" wand has an effective orifice of ~3/4".

About 60 CFM for one 3 stage hi-perf vac.

Lamb has printed all the graphs.

Those charts are what we use to figure series & parallel combinations.

Larry

 

[Greenie]

I read a 14" wand as having a much LARGER slot area, so Larry must be taking into consideration an educated guess with restriction in place of the wand lips against the carpet.

Other than that, I pretty much agree with him in reference to that chart, except I steer clear of Series configurations if at all possible, putting one motor BEHIND the first just adds 50% to the first motor's Waterlift, nothing to it's CFM, dollar for dollar I'd rather put that money into the CFM and hold steady on the waterlift I already had, I want over 120 REAL CFM at my wand, 60 REAL cfm centrifugal vacs don't cut it for carpet cleaning, flood work is a diferent story.

 

[Bill Soukoreff]

Greenie, is the vac you are using in that custom porty Vincent has a special model or can any one buy one? Is what is the model? You can PM me.

 

[Guest]

I agree with greenie; CFM to me wins everytime; At the intake of a jet engine; pressure is greatly increased for compression; suction that precedes the pressure is created in a convergent external force applied by pressure beginning at the area around the jet intake; that is what happens to the moisture in the air(or the cloud in front of the aircraft breaking or on the threshold of breaking the sonic boom); completely stripping all moisture enabling more heat from pressure and compression prior to entering the diffuser prior to combustion.

A simple way to discribe cfm is converging airflow reaching super sonic speed; creating pressure stripping moisture from the air/area of intake.

In the jet world it is demanded to have a continuous cfm/airflow be increased as far as design and fuel will allow. creating a convergent duct/wand opening allows for the harnessing of this power.

Sorry;

Old Jet Mech rambling on after a few Margaritas; lol

But remember this when choosing a wand!!! And think of this when considering the buying of glides; more air the more cfm!!!!!

 

[Bill Soukoreff]

But remember this when choosing a wand!!! And think of this when considering the buying of glides; more air the more cfm!!!!!

Remember what exactly?

 

[Larry Cobb]

Ashley;

If you look at the graph above you will notice:

1.The green graph - 137" Hi-Perf 3-stage

2.The purple graph - Two Std. 85" 2-stage vac in Parallel

At the typical operating point - 3/4", the green graph provides more recovery CFM & Lift.

Larry

 

[Greenie]

Yes Larry, they are very close at a 3/4" opening.

But a curious thing occurs at a 1" opening, the CFM is better by 50%, and only drops the water lift by 12%.

So I wonder....which is a more real life example of a glided 12" or 14" wand?