Go Back   VetteMOD.com > VetteMOD Workshop > Fabrication Section

Reply
 
Thread Tools
  #11  
Old 09-16-2015, 09:26 PM
Sam Cogley's Avatar
Sam Cogley Sam Cogley is online now
United States | Addict
 
Join Date: Apr 2012
Location: Springfield, MO
Posts: 557
My Photos: (0)
Default

Quote:
Originally Posted by 69427 View Post
Quote:
Originally Posted by Sam Cogley View Post
Find a cheap or free treadmill on Craigslist, the type that has a knob on the control panel attached to a potentiometer to vary speed.
I like that! Thanks.
No problem. It's a good way to upgrade band saws, drill presses, and other power tools to PWM-controlled DC power as well. Those things are rated to have humans running pushing against the bearings, they'll drill through things just fine. They usually have a speed controller board buried somewhere inside, usually near the motor. The units with push-button controls are harder to adapt, and there are a few old treadmills out there with AC motors and mechanical speed-change mechanisms.
Reply With Quote
  #12  
Old 09-16-2015, 09:34 PM
phantomjock's Avatar
phantomjock phantomjock is offline
United States | Addict
 
Join Date: Sep 2009
Location: Retired Again!
Posts: 1,131
My Photos: (639)
Default All I should say is; "Golly, Mr Wizard!"

Quote:
Originally Posted by 69427 View Post
I agree, but it just seems to me that a turning mechanical fan is going to block less air than a non-turning electric fan. (I can't easily prove it at the moment though.)
As I understand 12 fans - unless you lock it mechanically/electrically - it will free wheel (spin) without being "on". Minor - nearly immeasurable drag there I'd think.



Cheers - Jim (aka - Jimmy)
__________________
Rebuilder's Zen Saying:
One thought leads to another. If these thoughts link into a chain we become bound to the project. This bondage is subtle and remains until we complete the tasks -- or, STOP Thinking!
[Only registered and activated users can see links. Click Here To Register...]
Reply With Quote
  #13  
Old 09-17-2015, 12:50 AM
69427's Avatar
69427 69427 is offline
United States | The Artist formerly known as Turbo84
 
Join Date: Mar 2008
Location: Clinging to my guns and religion in KCMO.
Posts: 2,602
My Photos: (0)
Default

Quote:
Originally Posted by phantomjock View Post
Quote:
Originally Posted by 69427 View Post
I agree, but it just seems to me that a turning mechanical fan is going to block less air than a non-turning electric fan. (I can't easily prove it at the moment though.)
As I understand 12 fans - unless you lock it mechanically/electrically - it will free wheel (spin) without being "on". Minor - nearly immeasurable drag there I'd think.



Cheers - Jim (aka - Jimmy)
I hand spun one of my spare electric fans (for my street rod), and there's noticeable magnetic drag on it. I was somewhat curious if there was some way to get some "free" recharge energy out of it while cruising down the road, but between the magnetic drag and the inefficient pitch when used as a "turbine", instead of a prop, I'm not convinced that these things freewheel that well.
Reply With Quote
  #14  
Old 09-17-2015, 04:12 AM
Sam Cogley's Avatar
Sam Cogley Sam Cogley is online now
United States | Addict
 
Join Date: Apr 2012
Location: Springfield, MO
Posts: 557
My Photos: (0)
Default

I haven't felt much in the way of drag on my Mk. VIII fans when they're freewheeling.
Reply With Quote
  #15  
Old 10-24-2015, 06:36 PM
69427's Avatar
69427 69427 is offline
United States | The Artist formerly known as Turbo84
 
Join Date: Mar 2008
Location: Clinging to my guns and religion in KCMO.
Posts: 2,602
My Photos: (0)
Default

Pulled a motor out of a junked treadmill the other day. Two and a half horse DC motor. Hooked it up, and damn, the thing works.

[Only registered and activated users can see links. Click Here To Register...]

I still need to figure out the belt drive setup yet. The treadmill had a flat multi-groove belt on it, while I'd like to just be able to use a Vee belt and some of the spare pulleys I have laying around to get the fan speed I want.

[Only registered and activated users can see links. Click Here To Register...]

Looks like a threaded 7/16 shaft that the flywheel/pulley assembly is threaded onto. I'm trying to decide what's the easiest/cheapest way to put a regular vee pulley on it. I got a few ideas, but I just gotta take a closer look at some available pulleys to see what makes the most sense.

I've got the circuit board that controlled the motor speed (the control panel was digital, but I don't know yet if the signal to the motor board was analog or digital), and now I just gotta decide how much of it I want to use, and how much I want to bypass. I also need to decide the best/cheapest/decent-accuracy way to measure the fan RPM and the motor power consumption.
Reply With Quote
  #16  
Old 10-25-2015, 01:14 AM
Sam Cogley's Avatar
Sam Cogley Sam Cogley is online now
United States | Addict
 
Join Date: Apr 2012
Location: Springfield, MO
Posts: 557
My Photos: (0)
Default

I'd just plug in the motor control board and find a place to mount the speed control pot. That way you have PWM-controlled motor capable of anything from 0 rpm to the maximum rated rpm.
Reply With Quote
Reply


Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT. The time now is 07:08 PM.
 


Design by: vBulletin Skins Zone
Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.