I have used a dc treadmill motor (90vdc,15amp) and the controller that came with it on a 9x20 Jet metal lathe. I was looking to build a new controller that would give me 18-20 amps @ 90vdc with 120vac imput. Has anyone done this. Thanks NEWBIE Martin

 

You say you're a nube, whay projects have you built before?

I don't mean to sound discouraging but perhaps you shouldn't attempt this before you've built some other projects, even wimpy 120V mains is pretty dangerous.

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Thanks for your reply. To answer your question, I have a very limiled experience with solid state circuits but for 32 years I worked on standby generators from 2.5 kw to 2 megwatt set, so I try to be very careful with all electrical work. As I stated in my first post I removed the motor controller from a used treadmill (it was free) and was able to get it in a box and up and working. Years ago I built a Heathkit fish finder and a couple of other small projects. So now I wanted to try my hand at a little better controller at 90v dc 18-20 amps. The new motor I have is rated at that, so here I am looking for plans or suggestion on where to look.

 

I was given two brand new 1/2 hp, 90 vdc motors and I'd like to use them for my lathes (small benchtop lathes). The current requirements aren't quite so severe but my needs are similar. I was given a working controller - or so it is called. I hesitate with the word "controller" because of the feedback - or more to the point, I can't see that there is feedback in terms of RPM. I was told by a friend with some expertise in this area that many low cost DC motor controllers to sense RPM/load by the behavior of the DC motor load.

I've seen kits at the various electronics suppliers (PWM) that are rated for my motor but I had thought about modifying the output transistors (power FETs) and power supplies for more current.

Where I would like to take this someday is to have good, solid feedback (some kind of encoder) from the motor so that I can also drive the lead screw with a motor for threading.

I'm not much help here but have similar interests.

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stevez

 

It will make a difference as to whether the field is permanent magnet or wire wound. I presume it's the former. For that current range and with PM, there are lots of options, both commercial and DIY. For the DIY, I suggest going to a supplier of MOSFETS, such as International Rectifier, and checking their application notes. In the UK, there is a motor controller producer called 4QD that has lots of free information on its web site.

Personally, however, I would go with a commercial unit in that application. I have used units from KB Electronics (http://www.kbelectronics.com). On the popular internet auction site, you can find new units for about $130 USD. Even a simple commercial unit will offer braking, soft-start, and speed control feedback. John

 

I take it you also have an AC power supply available.

Build a small 12V linear power supply and use it to drive a controller with the MOSFET connected to the motor.

I'll post a simple schematic if you're still unsure.

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The OP is asking for 20 A at 90 V. How would a small 12 V power supply suffice?

 

The small 12V power supply isn't for powering the motor from but to power the PWM controller which drives the MOSFET that switches the motor.

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Please ask on the open forum if you have a question and I'll be happy to help, if I know the answer.

 

SteveZ, I first converted my 9x20 Jet lathe about 6 mo ago. I got most of the info for that from the 9x20 lathe Yahoo User Group( very helpful group). There are many users that have used perm mag type tread mill motors. That was the second Mod. I made to my lathe and if you are planning on threading, it's the best. I have seen many controller list from companies and E-bay but most are for Large (5 HP+) or 12v for RC type things. Because I got the first motor and controller free I used it to see if I liked it but being used I had no way to know how much it was used. So I found on the net NEW tread mill motors ($22 Each) but they are rated higher (90vdc/18amps/120ac/1 1/2 hp)than the old one (90vdc/12amps/120ac/1 hp. I have connected the new motors to the old controller for a short time and it did run and it sounds as if it was running fine (no load). The reason I am looking at upgrading the old controller or a new one is that because of the diff. between the two's HP rating and to get the extra HP. Hpe this helps Martin

 

General Electric Treadmill Motor Model #5KG46HR166 - eBay (item 350180932460 end time Apr-19-09 11:30:06 PDT)

Would something like this work? I'm actually working on a project of my own for a wind generator for a bigrig in conjunction with solar panels and batterys for storing the power. This is my first time using solar or wind for anything but I have to move in that direction as our company dont allow us to idle the trucks anymore and I have to stay cool or heated while I do my job, any help would be great thx in advance.

Will
St Louis MO USA