Home  |  Contents 

Electronics
  Forum Index : Electronics         Section
Subject Topic: Treadmill motor controllers Post ReplyPost New Topic
Author
Message << Prev Topic | Next Topic >>
Gizmo
Admin Group
Admin Group
Avatar
Administrator

Joined: 05 June 2004
Location: Australia
Online Status: Offline
Posts: 4654
Posted: 19 March 2018 at 2:51pm | IP Logged Copy link to clipboard   Quote Gizmo

Hiya

I'm building a new band saw for the workshop. I would like to use the band saw on both timber and metal, so need to run the saw at high speed and low speed. Initially I had planned to use a nice old 1/2hp induction motor, with the usual fan belt type of drive to the bottom wheel. But I do have a couple of DC treadmill motors, in the range of 1hp to 3hp.

So, having never used a treadmill motor before, I'm not sure on the best approach to drive it. I do have a motor controller for one of the motors, but it needs a PMW input to run and its old, the circuit board shows signs of corrosion.

I've seen Youtube videos where a standard $20 triac AC controller ( like for varying the speed of a universal motor ) is combined with a bridge rectifier to control the speed of a DC treadmill motor. I wonder how well this works, its certainly cheaper than a "proper" DC motor controller for that sort of voltage.

Has anyone played around with this sort of thing?

Glenn


__________________
"If it dont fit, use a bigger hammer."

The Back Shed
JAQ Software



Back to Top View Gizmo's Profile Search for other posts by Gizmo Visit Gizmo's Homepage
 
renewableMark
Guru
Guru
Avatar

Joined: 09 December 2017
Location: Australia
Online Status: Offline
Posts: 1090
Posted: 19 March 2018 at 4:13pm | IP Logged Copy link to clipboard   Quote renewableMark

I run a dc pump with something similar to this

What Amps/volts would you need?

__________________
Cheers Caveman Mark
Off grid eastern Melb
Back to Top View renewableMark's Profile Search for other posts by renewableMark
 
Tinker
Guru
Guru
Avatar

Joined: 07 November 2007
Location: Australia
Online Status: Offline
Posts: 1828
Posted: 19 March 2018 at 7:24pm | IP Logged Copy link to clipboard   Quote Tinker

Glenn, I built my own bandsaw more than 20 years ago and its still running fine. Its using just an old 1/2Hp washing machine motor (2 speed) and I also fitted a 2 speed pulley reduction. At the slowest speed that thing will cut 12mm steel plate.

Variable speed might be fine but not really necessary, as is a high power motor.

If you are interested, I can take a few pics of the dusty monster. Mine is a 3 wheeler, that gives me a much bigger throat (I can cut 600x300mm foam for example)plus a 3m+ long blade which runs a lot cooler with metal. The wheels are home made too - of hard wood!

One of the most useful things I ever built for my workshop.

__________________
Klaus
Back to Top View Tinker's Profile Search for other posts by Tinker
 
Phil23
Guru
Guru


Joined: 27 March 2016
Location: Australia
Online Status: Offline
Posts: 1544
Posted: 19 March 2018 at 7:55pm | IP Logged Copy link to clipboard   Quote Phil23

Gizmo wrote:
But I do have a couple of DC treadmill motors, in the range of 1hp to 3hp.


Treadmill motor sounds pretty cool.

Any idea of their speed range (m/s) & what diameter rollers they use?

Also, what sort of band speeds to the saws generally run at?
Only know saw chain gets up around 18-20m/s.

(Lol, and I've heard Salesmen quote 120km/h...).

Back to Top View Phil23's Profile Search for other posts by Phil23
 
Gizmo
Admin Group
Admin Group
Avatar
Administrator

Joined: 05 June 2004
Location: Australia
Online Status: Offline
Posts: 4654
Posted: 19 March 2018 at 10:28pm | IP Logged Copy link to clipboard   Quote Gizmo

I'll post the DC motor figures tomorrow Phil. A controller for the DC motors would need to run off the 240vac mains, and output 50 to 250 volts at a wild guess Mark.

I did have to replace a SCR in the motor controller for my little lathe a couple of months ago, and I thought the circuit was clever. It use 2 diodes and 2 SCR's wired as a bridge rectifier. Control was smooth and linear.

I guess PWM would be the best option thought for a DC motor.

Tinker I'll take some photos of mine over the next week as I build it. It uses 2 14 inch wheels made from 24mm MDF on a steel frame. I do have a small Ryobi band saw, very handy, but it keeps breaking blades due to the small wheels. I'm building this think based on what I could find in my junk pile. The 1/2hp motor is a nice looking 1950's Ozy made unit, will post a picture. I pulled it apart a few weeks ago, replaced a few wires, oiled it up and painted, looks the job.

Glenn



__________________
"If it dont fit, use a bigger hammer."

The Back Shed
JAQ Software
Back to Top View Gizmo's Profile Search for other posts by Gizmo Visit Gizmo's Homepage
 
Bryan1
Guru
Guru
Avatar

Joined: 22 February 2006
Location: Australia
Online Status: Offline
Posts: 878
Posted: 20 March 2018 at 7:09am | IP Logged Copy link to clipboard   Quote Bryan1

Hi Gizmo, Many years ago when I was setting my workshop off the grid I was using a 15Kva Onan gas fired genset and running 3 phase motors. I was lucky enough to secure some VFD's and worked with a guru who could program these to get the best performance out of them.

The first project was my Bridgeport mill where I fitted a new 2hp 3 phase motor wired in delta and programmed the vfd with the parameters to get the most out of the 2hp. Set the VFD to 100Hz so I could get double the speed and with a 3 wire control system, a 5K pot gives the speed control then one toggle switch is forward/reverse. Another toggle switch is ramp/coast so the spindle can stop straight away or just coast to a stop.

Next was my old 4' flat bed lathe again with a 2hp 3 phase motor and 3 wire setup. Now when machining if one starts to get chatter changing the Hz soon overcomes the problem making machining that much more easier.

My German toolroom lathe was already fitted with a 3/4 HP 3 phase motor so a smaller vfd was used. When machining under 1/2" the extra speed from the 100Hz available gets the speed needed for those fine accurate cuts needed.

I scored a VFD from a scrap yard and fitted that to a 3 phase blower fan I got from the flour mill so now I can go from from a gentle breeze to a gale force wind in a 4" extendable tube perfect for a oil burner.

I do have 1/2hp VFD and a 1/2hp 2 pole 3 phase motor to use on my surface grinder project and a spare 3hp VFD to use for other work around the shop.

VFD's aren't cheap to buy new but they can found at scrapyards cheaply and 3 phase motors can be found for peanuts.

I run everything of that 3Kw sinewave inverter I bought in '05 and now if I need even more grunt I can use my 16hp Listeroid Diesel with the 5Kw genhead.

Regards Bryan
Back to Top View Bryan1's Profile Search for other posts by Bryan1
 
Gizmo
Admin Group
Admin Group
Avatar
Administrator

Joined: 05 June 2004
Location: Australia
Online Status: Offline
Posts: 4654
Posted: 20 March 2018 at 9:14am | IP Logged Copy link to clipboard   Quote Gizmo

I did look at VFD's. Bit more than my budget, but I would like to play around with one one day.

This is the old induction motor.



It's a Crompton Pankinson, Australia made ( back when we made stuff ), 1/2hp 1435rpm motor. This is probably the easiest, most reliable and better looking option for the band saw.

I have 3 DC motors. A 180v 1.25hp 4000rpm, a 130v 2.5hp 6700rpm, and a 220v 3hp 3400rpm.

I found this circuit, looks similar to the circuit used to control my lathe DC motor.



Glenn


__________________
"If it dont fit, use a bigger hammer."

The Back Shed
JAQ Software
Back to Top View Gizmo's Profile Search for other posts by Gizmo Visit Gizmo's Homepage
 
Madness
Guru
Guru
Avatar

Joined: 08 October 2011
Location: Australia
Online Status: Offline
Posts: 2338
Posted: 20 March 2018 at 12:41pm | IP Logged Copy link to clipboard   Quote Madness

It would be possible to build a variable speed inverter just using the Ozinverter and making use of the variable frequency capability of the EG8010 chip.



__________________
Staying in my backshed where it is more peaceful!
Back to Top View Madness's Profile Search for other posts by Madness
 
Revlac
Senior Member
Senior Member
Avatar

Joined: 31 December 2016
Location: Australia
Online Status: Offline
Posts: 245
Posted: 20 March 2018 at 11:36pm | IP Logged Copy link to clipboard   Quote Revlac

Gizmo
Check if that motor has a centrifugal start switch or is it capacitor start?
Had one of those motors on the cement mixer and the centrifugal start switch failed at times and would stall the generator, could be a pain.

Cheers
Aaron
Back to Top View Revlac's Profile Search for other posts by Revlac
 


If you wish to post a reply to this topic you must first login
If you are not already registered you must first register

  Search the forums using Google.
 
Post ReplyPost New Topic
Printable version Printable version
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot delete your posts in this forum
You cannot edit your posts in this forum
You cannot create polls in this forum
You cannot vote in polls in this forum

Powered by Web Wiz Forums version 7.8
Copyright ©2001-2004 Web Wiz Guide

This page was generated in 0.1113 seconds.
Privacy Policy     Process times : 0, 0.02, 0, 0.1