« previous next »
Pages: [1] 2  All   Go Down

Author Topic: Chester Conquest mill power feed  (Read 23958 times)

Offline John Rudd

  • Hero Member
  • *****
  • Posts: 2525
  • Country: gb
Chester Conquest mill power feed
« on: July 08, 2009, 11:10:13 AM »
My motor for my power feed came today...

It's an ex Ford Fiesta wiper motor and should do admirably...

There was no scientific process involved in the selection guest a wild stab in the dark...

After all experimentation is what it's all about...

Here's a picture
Logged
eccentric millionaire financed by 'er indoors
Location:  Backworth Newcastle

Skype: chippiejnr

Offline John Rudd

  • Hero Member
  • *****
  • Posts: 2525
  • Country: gb
Re: Chester Conquest mill power feed
« Reply #1 on: July 08, 2009, 11:14:46 AM »
Having got the motor, I'm going to fit it to the left hand end of the mill table...No particular reason, just feels more comfortable for me.

I've tried ot remove the handwheel, but it's a bit stubborn..I may need to warm it with my hot air gun..or maybe resort to something a bit more brutish..

attaching the motor necessitates a plate mount to pick up on the two holes that hold the end plate to the mill table...2 hex steel pillars with an M6 thread should see to that...

Another picture...
Logged
eccentric millionaire financed by 'er indoors
Location:  Backworth Newcastle

Skype: chippiejnr

Offline John Rudd

  • Hero Member
  • *****
  • Posts: 2525
  • Country: gb
Re: Chester Conquest mill power feed
« Reply #2 on: July 08, 2009, 11:19:23 AM »
How to power the motor...I cobbled together a pwm speed controller using a 556 timer chip and a mosfet.

The 556 is a dual 555 timer, the pwm frequency is around 300Hz, annoyingly it makes the motor buzz at 0%...A little tweaking is needed to prevent this as it causes the mosfet to become all hot and bothered...Suffice to say when built it will have a heatsink attached...

An issue I identified with the circuit is the high component count, also there are no safety features...if the motor should become stalled, something is likely to fry...

So, current limited output or limit switches on the table?


So many choices and so little time....decisions.. decisions....Time for a lie down!
Logged
eccentric millionaire financed by 'er indoors
Location:  Backworth Newcastle

Skype: chippiejnr

Offline Darren

  • Madmodder Committee
  • Hero Member
  • *****
  • Posts: 3795
  • N/Wales
Re: Chester Conquest mill power feed
« Reply #3 on: July 08, 2009, 12:20:03 PM »
 Looking good so far, how many leads does your motor have, mine had 3.

I knew there was another reason I shied away from a timer circuit. I have mentioned it before but forgot to say when we last exchanged posts on this subject.

Some motors don't like timer/freq circuits cos it makes their windings "bounce". That's what you can hear buzzing. Not only can it heat the windings it can also damage the insulation.

Coils and transformers/chokes can have the same problems unless designed for PWM circuits.

Not trying to teach you to suck eggs, I just knew there was something I was forgetting to mention before.

Logged
You will find it a distinct help… if you know and look as if you know what you are doing. (IRS training manual)

Offline John Rudd

  • Hero Member
  • *****
  • Posts: 2525
  • Country: gb
Re: Chester Conquest mill power feed
« Reply #4 on: July 08, 2009, 12:30:12 PM »
My motor has two wires...single speed...flat out!...


I think to over come the buzz at 0% pwm, I'll use a switched pot to kill the power to the electronics...

Still mulling over( not milling... :clap: ) what to use for speed control, 556 or pic micro...Pic version will use less components and mean an easier pcb to design... :coffee:
Logged
eccentric millionaire financed by 'er indoors
Location:  Backworth Newcastle

Skype: chippiejnr

Offline Darren

  • Madmodder Committee
  • Hero Member
  • *****
  • Posts: 3795
  • N/Wales
Re: Chester Conquest mill power feed
« Reply #5 on: July 08, 2009, 12:36:11 PM »
I did consider pic, but it was way too far into new territory for me.

Now that would make an interesting write up to follow...... :thumbup:
Logged
You will find it a distinct help… if you know and look as if you know what you are doing. (IRS training manual)

Offline raynerd

  • Madmodder Committee
  • Hero Member
  • *****
  • Posts: 2893
  • Country: gb
    • Raynerds Projects - Raynerd.co.uk
Re: Chester Conquest mill power feed
« Reply #6 on: July 08, 2009, 12:52:43 PM »
Nice going John, I`ll keep watching with interest as this is the same milling machine I own.

I have reading  few thread on here about mill power feeds, I think Darren also has a thread. Why do you guys use standard electrical windscreen motors rather than hooking up a stepper motor? Electronics isn`t my strong point - but I just thought you`d have more control with a stepper?

Chris
Logged

Offline John Rudd

  • Hero Member
  • *****
  • Posts: 2525
  • Country: gb
Re: Chester Conquest mill power feed
« Reply #7 on: July 08, 2009, 12:58:53 PM »
2 reasons for going with the wiper motor....it was £6...

I'm a tight wad...tight Northern git whatever..

and pwm speed control is easy to do...

Steppers can be expensive and need a stepper control circuit...slightly more complicated...
Logged
eccentric millionaire financed by 'er indoors
Location:  Backworth Newcastle

Skype: chippiejnr

Offline raynerd

  • Madmodder Committee
  • Hero Member
  • *****
  • Posts: 2893
  • Country: gb
    • Raynerds Projects - Raynerd.co.uk
Re: Chester Conquest mill power feed
« Reply #8 on: July 08, 2009, 03:01:50 PM »
OK - I understand. So basically a stepper would do the same job just at a greater expense.

 Good luck with the rest of the mod, I`ll be watching!!

Chris
Logged

Offline Darren

  • Madmodder Committee
  • Hero Member
  • *****
  • Posts: 3795
  • N/Wales
Re: Chester Conquest mill power feed
« Reply #9 on: July 08, 2009, 06:01:35 PM »
John, what do you mean by 0%?

zero voltage or full voltage output?

Or should I say fully chopped or full intact wave?
Logged
You will find it a distinct help… if you know and look as if you know what you are doing. (IRS training manual)

Offline John Rudd

  • Hero Member
  • *****
  • Posts: 2525
  • Country: gb
Re: Chester Conquest mill power feed
« Reply #10 on: July 12, 2009, 01:25:14 PM »
Ok,

Things have moved on slightly on the speed control front...

The 555 timer thing is pants...Try as I might I cant get it to control the motor speed at a decent rate...Changing some of the component values makes things worse..

A change of tactic is required...

So, on to a redesign....
Logged
eccentric millionaire financed by 'er indoors
Location:  Backworth Newcastle

Skype: chippiejnr

Offline Mike K

  • Full Member
  • ***
  • Posts: 114
  • Country: us
Re: Chester Conquest mill power feed
« Reply #11 on: July 12, 2009, 09:41:16 PM »
Darren, I think John is referring to duty cycle.

Mike
Logged

Offline Darren

  • Madmodder Committee
  • Hero Member
  • *****
  • Posts: 3795
  • N/Wales
Re: Chester Conquest mill power feed
« Reply #12 on: July 13, 2009, 04:20:39 AM »
Ah yes, that's would be it,

Thanks Mike...


John, do you think that maybe there could be a miss match here between the DC motor and the AC signal you are feeding it?
Logged
You will find it a distinct help… if you know and look as if you know what you are doing. (IRS training manual)

Offline John Rudd

  • Hero Member
  • *****
  • Posts: 2525
  • Country: gb
Re: Chester Conquest mill power feed
« Reply #13 on: July 13, 2009, 06:24:15 AM »
Err....probably...My guess would be the inductance of the motor is having some sort of effect.... :coffee:
Logged
eccentric millionaire financed by 'er indoors
Location:  Backworth Newcastle

Skype: chippiejnr

Offline Darren

  • Madmodder Committee
  • Hero Member
  • *****
  • Posts: 3795
  • N/Wales
Re: Chester Conquest mill power feed
« Reply #14 on: July 13, 2009, 06:39:48 AM »
Yes, that sounds plausible,

Do you have a simple dual voltage secondary transformer? If so why not give it a go with just two voltage outputs and switch between them?

I'm sure you know what I'm suggesting, but for others, mains-fuse-transformer voltage in 240V-transformer voltage out 6/12V-rectifier to DC,

The outputs will be slightly higher due to being rectified but close enough. I really don't think the actual speed of the wiper motor is that critical from my exp, just so long as you have a fast and a slow speed for convenience.


I must rig this up sometime and test it in real life as I promised to sort something out for Stew. But I think it will work fine and would be rock solid reliable (unlike fancy electronics)

Just a suggestion.
Logged
You will find it a distinct help… if you know and look as if you know what you are doing. (IRS training manual)

Offline John Rudd

  • Hero Member
  • *****
  • Posts: 2525
  • Country: gb
Re: Chester Conquest mill power feed
« Reply #15 on: July 17, 2009, 04:13:14 AM »
Having spent some time pondering at the mill....I'm wondering whether this is a viable and worthwhile project.. :coffee:

I removed the handwheel to access the X axis leadscrew bearing support plate...a quick measure up and the bolt holes for it are very close to the mounting holes for the motor.... :bang:

My intent was to make a mounting plate that picked up the two bolt holes for the bearing support plate and make some long spacing bolts that would replace the existing bolts, the new mounting plate fitting on the end of the new bolts...

So a rethink...do I continue or bin the idea? Choices choices choices.....
Logged
eccentric millionaire financed by 'er indoors
Location:  Backworth Newcastle

Skype: chippiejnr

Offline Darren

  • Madmodder Committee
  • Hero Member
  • *****
  • Posts: 3795
  • N/Wales
Re: Chester Conquest mill power feed
« Reply #16 on: July 17, 2009, 06:07:26 AM »
Bit difficult to tell from here John, a picture of the problem may help....
Logged
You will find it a distinct help… if you know and look as if you know what you are doing. (IRS training manual)

Offline John Rudd

  • Hero Member
  • *****
  • Posts: 2525
  • Country: gb
Re: Chester Conquest mill power feed
« Reply #17 on: July 17, 2009, 06:23:09 AM »
Ok,

Here are some pictures of the leadscrew bearing plate, motor mounting points and where the bearing plate fits.

As you can see, the bearing plate is secured with two M6 cap head screws to the table, the distance that these are apart is say X mm, nowlook at the motor mounting points, two appear in a straight line( the top onse...) they are Xmm plus a bit apart...
Logged
eccentric millionaire financed by 'er indoors
Location:  Backworth Newcastle

Skype: chippiejnr

Offline John Rudd

  • Hero Member
  • *****
  • Posts: 2525
  • Country: gb
Re: Chester Conquest mill power feed
« Reply #18 on: July 17, 2009, 06:25:40 AM »
My intenton was to mount the motor on a plate that would bolt to the table using the existing tapped holes...


Driving the leadscrew next...I was thinking of a sliding dog clutch, the fixed part on the leadscrew and themoving part on the motor...Sorry no pictures of that as yet....its all in my head as they say..
« Last Edit: July 17, 2009, 06:27:27 AM by John Rudd »
Logged
eccentric millionaire financed by 'er indoors
Location:  Backworth Newcastle

Skype: chippiejnr

Offline Darren

  • Madmodder Committee
  • Hero Member
  • *****
  • Posts: 3795
  • N/Wales
Re: Chester Conquest mill power feed
« Reply #19 on: July 17, 2009, 06:27:20 AM »
My first thoughts are an off set threaded rod?

Take a bar say 15mm (aprox) off set it by half the plus a bit and thread it 6mm.....?
Logged
You will find it a distinct help… if you know and look as if you know what you are doing. (IRS training manual)

Offline John Rudd

  • Hero Member
  • *****
  • Posts: 2525
  • Country: gb
Re: Chester Conquest mill power feed
« Reply #20 on: July 17, 2009, 06:29:38 AM »
I thnik I know what you mean...
I could thread one end to screw back into the table, the other end of the bar tapped offset....yes?
Logged
eccentric millionaire financed by 'er indoors
Location:  Backworth Newcastle

Skype: chippiejnr

Offline Darren

  • Madmodder Committee
  • Hero Member
  • *****
  • Posts: 3795
  • N/Wales
Re: Chester Conquest mill power feed
« Reply #21 on: July 17, 2009, 06:31:09 AM »
Second thoughts, you don't need two fixing points as the leadscrew becomes one itself.

Bit like this

Logged
You will find it a distinct help… if you know and look as if you know what you are doing. (IRS training manual)

Offline Darren

  • Madmodder Committee
  • Hero Member
  • *****
  • Posts: 3795
  • N/Wales
Re: Chester Conquest mill power feed
« Reply #22 on: July 17, 2009, 06:31:49 AM »
Quote from: John Rudd on July 17, 2009, 06:29:38 AM
I thnik I know what you mean...
I could thread one end to screw back into the table, the other end of the bar tapped offset....yes?

Yes that sounds like what I was thinking... :thumbup:
Logged
You will find it a distinct help… if you know and look as if you know what you are doing. (IRS training manual)

Offline Darren

  • Madmodder Committee
  • Hero Member
  • *****
  • Posts: 3795
  • N/Wales
Re: Chester Conquest mill power feed
« Reply #23 on: July 17, 2009, 06:35:27 AM »
I made a dog clutch originally for mine, didn't stay with it though. No real reason as it worked well enough but I just got carried away

Have a look here and scroll down a bit....http://madmodder.net/index.php?topic=1050.msg8336#msg8336
Logged
You will find it a distinct help… if you know and look as if you know what you are doing. (IRS training manual)

Offline John Rudd

  • Hero Member
  • *****
  • Posts: 2525
  • Country: gb
Re: Chester Conquest mill power feed
« Reply #24 on: July 17, 2009, 06:45:52 AM »
So a potential solution, a question tho'

The pillars are threaded to go into the mill table, the other end s are tapped but offset..

How do I know that when the pillars are screwed home into the table that my threaded holes at 'tother end will line up to meet the motor mounts?
Logged
eccentric millionaire financed by 'er indoors
Location:  Backworth Newcastle

Skype: chippiejnr
Pages: [1] 2  All   Go Up
« previous next »