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Posted:
Fri Feb 18, 2005 8:19 pmby Thomas Vaught
See this site:
I have talked to them and the blowers are pretty well engineered.
You could also "copy" the way the blower is mounted with the electric motor and do a pretty good job with a regular Paxton/ Vortech blower off of e-bay.
JMO
Tom V.
Posted:
Fri Feb 18, 2005 9:00 pmby 86rocco
Nice, that's what I call a blower!
Posted:
Sat Feb 19, 2005 9:31 pmby 84-1074663779
A very nice solution to the blower problem to be sure, there are a couple of things to keep in mind.
The first is required blower drive power. A centrifugal supercharger would make a very fine flow bench blower, but the electrical power required to reach maximum rated output may be more than you have available.
As a rough guide Hp = CFM x psi /229 (where 28" is 1 psi) That is for an impossible to reach 100% blower efficiency. Assume most supercharger blowers fall into the 50% to 75% efficiency region. Drive Hp could double from that 100% efficiency figure.
If you can get a flow map, drive power is easy to estimate, if Hp curves are not already provided.
See what sort of mains power you have available first, and design around that, because in the end that is what is going to limit what you can do.
The other difficulty can be blower surge. The higher the efficiency, usually the more sudden and violent the onset of surge can be. Just throttling a centrifugal supercharger might create violent surge at low flows. Many ways around this, but a variable speed motor is the best solution. It will dramatically cut down noise and power consumption when only doing small jobs.
Posted:
Sat Feb 19, 2005 11:39 pmby Thomas Vaught
The web site I provided motors use 220 three phase in most cases
(something that most homes do not have. A business deal would
be no problem though.
Testing at 80 inches of water would be nice for bragging rights but I believe I could get by easily at half that test pressure. (40 inches).
The unit I was look at could move 600 cfm at 40 inches of water
pretty easily with a relatively small motor I was told like a 10 hp 3 phase.
Tom V.
The old paxton flow bench that Hot Rod wrote about MANY years ago used a 220 volt 3 phase 10 hp motor also.
Posted:
Sun Feb 20, 2005 5:10 pmby 84-1074663779
That power figure sound about right, I have a bit less flow and a bit more pressure available with my 10 Hp motor, but it still requires just over 13 Amps per phase at 240v to do it.
My 18" rotor runs at up to 6,000 Rpm, but a 3" rotor running at 36,000 Rpm would be pretty comparable I should think.