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spindle speed problems
« on: February 26, 2013, 07:55:04 AM »
i am in the process of finishing a total refit  of a 1983 denford orac cnc lathe , all the electronics ,stepper motors & main spindle motor have been replaced with new upto date items .
everything has gone fairly easy until recently when i am trying to set up the spindle & i can't get anything to work properly.if i am in manual mode & using the mdi line put in m3 s500
what i get will something like
S true = 1750 rpm
s box = 500 rpm
but the spindle speed using a hand held tacho = 800 rpm
i have tried the spindle calibration screen , it starts the spindle at 250 rpm & stops at this 30 mins so i stop it because it is going knowwere
everything else is working fine , stepper motors , homing switch's
machine spec
parallel port board , 2 stepper drive boards , spindle board (step & direction converted to 0 to 12v for inverter control ) all these items came from www.diycnc.co.uk these are the system 4 system on his website  , the spindle inverter is an imo idrive - idx 1hp , the motor is a dual voltage 3 phase 3/4 hp 1370 rpm , it has a cnc4pc c3 index pulse board settings are active = low
output = ttl
the spindle index disc has 4 slots with the largest being 12mm wide
i have spent the last 2 days changing settings & try again still no joy
please has anybody any ideas as to what i am doing wrong or something i am overlooking
i am enclosing my xml for you to have a look at to hopefully see my problem
robert
« Last Edit: February 26, 2013, 08:05:57 AM by ministeam »
Re: spindle speed problems
« Reply #1 on: February 26, 2013, 09:30:06 AM »
try these settings for the spindle.

steps per 2000
velocity 60
acceleration 125

start the spindle on 1000 and use your tacho to read the correct rpm, adjust the velocity up to give you a reading that matches.

do you have the spindle pulley set to 100 min and 2500 max
Re: spindle speed problems
« Reply #2 on: February 26, 2013, 09:50:25 AM »
thank you for your quick reply i will go into the workshop & try it now
something i forgot to put on my earlier post is is the spindle is driven by a poly v belt & the motor pulley is 40mm dia & the spindle pulley is 60mm dia, would this make any diference to what you have suggested i should try
robert
Re: spindle speed problems
« Reply #3 on: February 26, 2013, 09:59:12 AM »
A fellow ORAC retro-fitter, awesome!  Please post up some pics in the machines "Show n' Tell" section.  I'd love to see how you've done yours.  Mine's in there someplace.  Yours have the toolchanger?

As to your spindle, you're gonna need to close off all but one of the holes in your spindle sensor disc.  AFAIK, Mach3 will only work with one pulse per rev.  Mach4 possibly will work with more???
Milton from Tennessee ya'll.
Re: spindle speed problems
« Reply #4 on: February 26, 2013, 10:02:38 AM »
thank you for your quick reply i will go into the workshop & try it now
something i forgot to put on my earlier post is is the spindle is driven by a poly v belt & the motor pulley is 40mm dia & the spindle pulley is 60mm dia, would this make any diference to what you have suggested i should try
robert
I can't remember what the orac gearing is, so i'm not sure on that one. Also make the index debounce 0 ( general config, click ok )
Re: spindle speed problems
« Reply #5 on: February 26, 2013, 11:16:09 AM »
hi angeltech
i have changed the motor settings to the ones you suggested & yes the debounce is set to zero , on my first try with the new settings the spindle worked as it should with the s dro showing
1000 rpm  s true dro very erratic with a range of 100 rpm (50 rpm either side of 1000 )  tacho gave a reading of 1000 rpm
i next tried a speed of 750 ,  the s true dro gave a reading of 1000 as above still erratic tacho gave a reading of 850
next i tried 500  , the s true dro gave a reading of 750 , the tacho gave reading of 850 still very erratic
the inverter in earlier tests does like running at low speeds seems it only likes at speeds 500 rpm
robert
Re: spindle speed problems
« Reply #6 on: February 26, 2013, 11:19:51 AM »
have you set the spindle pulley.

What inverter are you using, the original?
Re: spindle speed problems
« Reply #7 on: February 26, 2013, 12:48:53 PM »
hi angeltech
yes i have set the spindle pulley to 100 to 2000 ( i had it originally set 250 to 1800 ) with the ratio set to .60
the inverter is one that i bought from transwave here in the uk , it is from there economy range  but from a well known manufacture IMO .i have had a good few converters & inverters from transwave peter who does all the model engineering exhibitions is very knowledgeable on the products he sells
robert
Re: spindle speed problems
« Reply #8 on: February 26, 2013, 12:53:00 PM »
is the output set to 100hz on full speed
Re: spindle speed problems
« Reply #9 on: February 26, 2013, 12:56:00 PM »
why the ratio?