vac question

[phenning]

What is a preferred configuration for a portable...2/3 stage vacs in par. or 3/2 stage vacs in a series? And why is one better than another?

 

[Greenie]

you wanna clean carpet or suck flood water?

carpet = A
Flood = B

But I would venture an educated guess that two 3 stage high water lift vacs in series would perform Better on the flood sucker...amp for amp.

as to why....

that is a whole new thread....I'll sum it up in "my" view, look at the contents of the wand vac hose, if it's 10% water (light weight) and 90% air...the Air parallel high cfm configuration works better, if it's 90% water the high waterlift moves the heavy water better...hence my preference for high lift vac motors in series.

 

[Bob Savage]

And, there is a better way of putting 2 vac motors in series.

Instead of connecting the intake of motor #2 into the discharge port of vac motor #1, as all of the electric vacuum motor series connections that I have seen are connected, instead, connect the intake of each vac motor into a Y, and then connect the remaining vac port of the Y, to the single stack in the portable.

This will give you more suck and allow each motor to perform much better, and last longer!

 

[Eric Valentine]

And, there is a better way of putting 2 vac motors in series.

Instead of connecting the intake of motor #2 into the discharge port of vac motor #1, as all of the electric vacuum motor series connections that I have seen are connected, instead, connect the intake of each vac motor into a Y, and then connect the remaining vac port of the Y, to the single stack in the portable.

This will give you more suck and allow each motor to perform much better, and last longer!

Err.....that would be putting them in parallel.

 

[Greenie]

Series adds roughly 50% of the waterlift of the second vac motor to the full waterlift of the 1st vac motor, and Nothing to the CFM, so for demonstration purposes if the vacs both had 100" waterlift and 100 cfm to start with, your series configuration for your flood sucker woudl have 150" water lift... and the same 100cfm.

Unless I'm missing something, what Bob described is a Y splitter and leaving the vacs in air parallel which would double the cfm and leave the water lift the same as a single vac.

 

[Bob Savage]

Nope, air parallel would be each vac having it's own separate stack into the recovery tank.

The way I described, in series, is both motors discharge into open air, not one into the other.

The Y splits the two motors but draws from a single stack. Parallel takes 2 stacks.

 

[Eric Valentine]

Nope, air parallel would be each vac having it's own separate stack into the recovery tank.

The way I described, in series, is both motors discharge into open air, not one into the other.

The Y splits the two motors but draws from a single stack. Parallel takes 2 stacks.

The ONLY way to get air series with vacuum motors is to have the exhaust (output) of one feeding into the inlet of the next motor. Air parallel is achieved when the inlets of 2 or more vacuums are plumbed to a common point (in this case, a Y connector). Ideally, you should have 2 stacks for the motors when in air parallel, so they each have independent air feeds from the tank, if the stacks are 1.5". If there is a real 2" stack to feed both motors, then you will still be okay for airflow, as long as any bends in the top of the stack are not too sharp, or choke down the airflow.

As for the answer to the original question, Greenie has answered it very well. Series is better for extracting water (flood work), and parallel is better for cleaning, where the added airflow will extract more water from the fiber.

 

[Bob Savage]

Eric,

What I've suggested here is another way of plumbing 2 electric vac motors.

If, for some reason, you don't think it will work, or that it is not a correct way to install 2 vac motors in an electric configuration, or you don't like it called series, you are certainly entitled to your opinion. I'll call it parallel lift configuration, if you think that sounds better.

I've done extensive testing with many different electric vacuum motor configurations over the past 25 years, so that's where my tip (comment) came from.

 

[Eric Valentine]

Parallel lift sounds great. In fact 2 motors hooked to a Y is the way I want to hook up dual 3-stage motors when I can afford to pimp my porty. I only have one stack, but it is 2" all the way, so that shouldn't be a problem for airflow.

 

[John LaBarbera]

Hi Paul,

Just my personal opinion. Vacuum motors performance varies. But let's say, to answer your question, the choice is for 2 three stage vacs(148" h20/115 cfm) in air parallel would give you 230 cfm and 148" h20, about 13 amps per cord. 3-HP 2 stage (107" h20 and 100 cfm) in series would produce about 220-230" h20 but cfm would drop to about 70 cfm, about 20 amps on cord one and 11 to 12 amps on the second cord. (this is how a vacuum motor company described it to me) As you can see you get more bang for the buck and bang for the amps with dual 3 stage vacs in air parallel, especially if you are going longer hose runs.

John

 

[phenning]

Thanks for all your input.