more MCD bench stuff, motor controller

[cboggs]

This is a great thread, .. as I'm building one of these benches
from the plans, .. and having questions.

OK, .. I'd like to put all the motors ( 9 ) on one power switch
but have a speed controller to turn them down. Problem is
9 motors draws a TON of amps, .. anyone know of a riostat ( sp?)
or conrtoller that can do that??????

I noticed the superflow 1020 has a riostat or variac on it, .. anyone
know what that is.

OK I bought Deywer manometers, .. for the inclinded, do I need
to use the blue fluid like a SF-600? also, .. where can I get a % scale
for it like on the SF-600???????

There is a discussion about a diflector plate under the 4" hole, ..
does this need to be done????

Curtis

[JRM]

What i did was special order the incline manometer from dwyer. I cant rhember how much it was though.

As for controling my motors i used 4 switches and relays. Each switch controls 2 motors. I went by what the manafacture said each motor flows in cfm. so basically each pair of motors flows 200 cfm. My theory was if i run 1 set of motors there is 200 cfm pulling, if i turn on 2 sets then there was 400 cfm etc. Granted i did not compinsate for the vacc lost by just running 1/2 the motors. A buddy of mine is an electrical wizzard/engineer and he said that we could go vary speed on the motors but you would need to get motors that were designed to do that so the motors would not prematurely burn out due to excessive heat build up.
another idea i had was to add a valve to the vaccume motor chamber so i could basically bleed off the extra vacc if and when i did lower flow values

[Mouse]

Air valves make it much easier to control air pressure. This is because the pressure changes are instant. Motors require time to speed up and slow down, making pressure adjustment an exercise in frustration for both man and machine.

John

[larrycavan]

Which Dwyer manomete model did you buy for the inclined and which one for the verticle?

[84-1074663779]

Variable speed can be obtained by using a suitably rated variac.

Be cautious where the airflow through the blower is used to cool the motor. If you pull high vacuum at low flows that requires significant blower power, the motors could seriously overheat. Vacuum cleaner motors are made to run with fairly restricted flow, and others seem not to have had any problems. But just be aware of what could happen if you block ALL the flow and then run the motors flat out.

[Thomas Vaught]

e-mail me at boostengineer@comcast.net

I might have a percent scale that will work for you.

I had several made some years ago and would just need to find them.

They were made by the people who made your incline.

Dewyer.

Tom V.

[cboggs]

I'll have to check the part numbers for the manometers, ..
but I think the inclined is a durablock #246 0- 6" water.

and the virticals are #1230 36" h2o. I'd like to have 48" but I didn't
see that on the web site when I ordered, .. but my custom order.

Tom, .. if you have percent scale for the inclined I would
really, .. really, like to get one from you.
Will I need the blue fluid for that or is the red going to be OK ???

I'll drop you an e-mail.

I think I'm going to bag the vair speed motor idea and just put them
om multi switches. I have nine motors so I'll split them onto three
switches. If I'm not running all the motors, will the leak from the
non-running motors be a problem??

Thanks gang,

Curtis

[larrycavan]

That Dwyer manometer is designed for a 6" pressure drop. If you can't find a scale, I can give you the formula to make your own. Off the shelf Dwyer inclined manometers come calibrated with scales to use the red .826sg fluid. If you're making your own scale, I would use either the violet 1.0sg fluid or distilled water and the Dwyer green wetting agent. The formula is for using 1.0sg fluid. It can be easily modified for using .826sg or any other specific gravity. Remember, distilled water can freeze. You have to decide on that before you start your scale. An accurate machinists ruler, square and a scribe are all you need to mark your scale lines. I mad mine out of a piece of thin, polished aluminum.

Best Regards,
Larry