Almost ready to start building

[Bambi4010]

I've been poking around here since summer & have a set of plans in hand. Now I need to get everything else on order & start making sawdust.

I probably will need to reread everything with a notebook in hand, but have a couple of questions that I;m pretty sure have not been answered.

First, on the 40" PTS controller, can it handle up to 40" of test depression, or only 40" of total depression (test depression + orifice pressure drop)?

Second, I'm thinking a 6 motor bench (with PTS check valves for a future upgrade to 8) but anticipate only needing 4 motors to get the flow I need for now. Aside from noise level & convenience, what are the advantages and disadvantages to controlling all motors vs 2? Is there a difference in the electricity used?

Thanks,
Mark

[Brucepts]

The 40" tops out around 36" of actual usable test pressure. The cfm scale works on a 16" sensor.

After building both now a full motor control and a 2 motor control with extra motors switched on as needed, I will never personally build a switched motor bench. I like the full motor control, simple to wire no need to worry about check valves, relays or heavy duty switches.

I'll more than likely go back and rewire my first bench to a full motor control. My next flowbench will be built that way and all future PTS in-shop builds will also be that way.

[Bambi4010]

From your build pics it looks like you wired them all in parallel off the motor controller? I presume they are 220 motors. Where did you find the large amp controller or do you have them availible to sell? What about a source for the relay?

Would it make sense to put 4 motors on a 25A controller & then add a second 25A controller if & when I add more motors? It looks like Payne has an open chassis 240V / 25A unit for $99.

Thanks,
Mark

[Brucepts]

This is a supplier of solid state relays:

http://www.hbcontrols.com/store/phase-a ... tegory.asp

The hbcontrols setup still needs a 220v/24v transformer which they sell but it's costly. eBay is your friend here locating a transformer.

I do sell them from time to time as I locate parts and make my own 75amp controls. This is usually discussed in the PTS Plans area. I use a 75amp solid state relay (SSR) so it is more than oversized for this application, they cost the same as a smaller amp SSR relay when I find them on eBay. The SSR needs to be a "random fire" style.

The motors in the second build I show in the PTS Plans area are 220v, my first bench build had two motors 120v in series for the motor control and check valves on switched motors. I'll just go back and re-wire the other sets of 120v motors to series and put them on the 75amp motor control.

I used the Payne control on my first flowbench build and it worked fine. I swapped over to the SSR as the control is so much more precise using a 10 turn pot. Using the SSR allows you to also hookup the PTS automatic motor control (PID) at some point for those interested.

[Bambi4010]

Thanks much for the info.

[Tony]

After building both now a full motor control and a 2 motor control with extra motors switched on as needed, I will never personally build a switched motor bench. I like the full motor control, simple to wire no need to worry about check valves, relays or heavy duty switches.

The noise level will also be considerably less, and as all of the motors will be running together at much less than absolutely flat out maximum speed (most of the time), they will run cooler, and slower, and last a lot longer.