By continuing to use this site, you agree to our use of cookies. Find out more
Forum sponsored by:
Forum sponsored by Forum House Ad Zone

Warco WM180 motor control

All Topics | Latest Posts

Search for:  in Thread Title in  
modeng200028/10/2010 16:23:08
340 forum posts
1 photos
I am trying to find information about the motor control circuit board fitted to my Warco WM180 lathe. The user speed control on the front of the lathe used to take the chuck speed down to zero as suggested by the speed selection label however now I can not reduce the speed below 200rpm.
 
There are two preset potentiometers on the cct board, one for min revs and the other for max. The min rev setting is at the lower limit of rotation so there is no more adjustment available.
 
The information I have from the circuit board is that it is by Best Control Inc (Taiwan) and is a BC 2000TA DC motor control board.
 
I have in the past asked Warco if they would supply me with information about setting up the motor control board but to no avail. It seems a bit over the top to take the lathe back to them or to call them out for a service call to adjust a nominally working machine.
 
Some while ago I used the lathe to wind the solenoid coils for my ME Clock but I couldn't now as it runs too fast.
 
John 
 
 
 
 
 
 

Edited By modeng2000 on 28/10/2010 16:39:25

Chris Kelland28/10/2010 17:00:28
10 forum posts
Hi John,
 
I take it you have rung Warco?
 
If not give them a ring 01428 682929 extension 209  and ask to talk to Eric or Chris they are the tech engineers and very helpful.
 
 
Chris.

Chris Kelland28/10/2010 17:14:36
10 forum posts
Hi John,
 
You could also look at this link, there is a bit of info on the control board.
 

http://andysmachines.weebly.com/index.html
 
 
Chris
john swift 128/10/2010 17:27:37
avatar
318 forum posts
183 photos
Hi John
 
if Warco can't help
 
have a look at the control board
If your lucky the speed control board will have preset's for  the maximum and minimum speed marked on the pcb 
(make a note of the position before adjustment of the minimum speed)  
 
if not and you have the wiring diagram for you machine
you could disconnect the +10v or +12v supply form the speed control to prove
that with a control voltage of 0v the speed is 0 rpm
 
two diodes can be used to give a 0.6v volt drop to the control voltage to give a small reduction in speed
 
I'll post a diagram

 
 
       John 
  

Edited By john swift 1 on 28/10/2010 17:48:41

Edited By john swift 1 on 28/10/2010 17:49:22

john swift 128/10/2010 18:43:32
avatar
318 forum posts
183 photos
missing from previous post
 
with the speed control fully anticlockwise the control voltage may not be zero
(the mechanical end stop may stop the wiper reaching the end of the resistive track)
 
also the minimum and minimum speed presets interact
 
so far I can not find the circuit of KB Electronics speed controls used in your lathe
 
 
     John 
 
 
 
 
modeng200028/10/2010 20:05:30
340 forum posts
1 photos
Thanks for the replies, all very interesting.

The minimum preset is at minimum so I can't get any more reduction from there. If the max and min resets interact I might be able to 'shift' the speed control range down by careful adjustment but don't hold much hope for this aproach. Something has changed because I was able to reach almost zero speed when the lathe was new.
 
Chris, I'll ring Warco again, it is now some time since I last tried and perhaps I did not speak to the best person then. The link to andysmachines is quite informative, thanks.
 
John, I have tweeked the speed presets and know where they were before touching them. however this has not helped to reduce the lowest speed. I was hoping for a circuit diagram of the pcb so I could understand how the speed presets function.
 
John
john swift 128/10/2010 21:50:02
avatar
318 forum posts
183 photos
Hi John
 
found a low res circuit that may help

   
 
the max speed preset pot sets the voltage across the speed control
 
the min speed preset adjusts a bias voltage to the first op amp
 
it may be worth checking all the electrolytic capacitors on the board
 
( if you can measure the ESR ) 
 
 
      John

Edited By john swift 1 on 28/10/2010 22:03:27

modeng200029/10/2010 11:28:38
340 forum posts
1 photos
Things are not quite like your circuit John. It turns out that the 3 pots, Max, User control and Min are all in series across the supply rails. So with the Min at zero volts I suspect there has been a change elsewhere in the circuit.
 
I shall go round with my Fluke and make sure that the zero setting is indeed zero volts.

John
john swift 129/10/2010 15:09:00
avatar
318 forum posts
183 photos
Hi John ,
 
so far i've only found a picture of your control pcb
 
but have not found the circuit of it or similar looking kb electronics control
 
it looks like you will end up reverse engineering your board !
 
as I did a the start of the year , with my CL300 minilathe
 
    John
Billy Mills29/10/2010 15:57:08
377 forum posts
John
 
Don't know your machine but wonder if there is an opto tacho connected to the corner connector. Would suspect that a dirty or failed slot sensor could produce the fault. With no tacho signal the controller would run above the set min speed. Would never rush in to modify stuff without understanding what we are dealing with.
 
Regards
Alan
modeng200029/10/2010 16:37:01
340 forum posts
1 photos
Alan,
 
The opto tacho is working normally in that it displays the actual spindle speed changing as the cutting load varies. As far as I can tell the tacho is independant of the motor control circuit.
 
John
modeng200029/10/2010 16:40:23
340 forum posts
1 photos
John,
 
Now I have a fair idea as to what is going on with the motor control I could end up reverse engineering. At least it seems to use a quad op amp LM324, one of my favourite chips.
 
John

All Topics | Latest Posts

Please login to post a reply.

Magazine Locator

Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!

Find Model Engineer & Model Engineers' Workshop

Sign up to our Newsletter

Sign up to our newsletter and get a free digital issue.

You can unsubscribe at anytime. View our privacy policy at www.mortons.co.uk/privacy

Latest Forum Posts
Support Our Partners
cowells
Sarik
MERIDIENNE EXHIBITIONS LTD
Shopping Partners
Subscription Offer

Latest "For Sale" Ads
Latest "Wanted" Ads
Get In Touch!

Do you want to contact the Model Engineer and Model Engineers' Workshop team?

You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.

Click THIS LINK for full contact details.

For subscription issues please see THIS LINK.

Digital Back Issues

Social Media online

'Like' us on Facebook
Follow us on Facebook

Follow us on Twitter
 Twitter Logo

Pin us on Pinterest

 

Donate

donate