Hello Guest it is July 20, 2019, 06:20:42 AM

Author Topic: Stepper motors  (Read 3103 times)

0 Members and 1 Guest are viewing this topic.

Re: Stepper motors
« Reply #10 on: October 13, 2017, 10:30:28 PM »
Hi,
you are correct, steppers are inclined to lose steps at speed and the faster you go the worse it gets.

A stepper with a reasonable drive should do 1000 rpm. It may not have much torque at that speed so you can't expect it to drive a heavy load
unless you put outsize steppers just so that you'd have the grunt leftover at 1000 rpm.

It won't do any harm to try.

What size steppers and what torque specification are you using? What voltage are your drivers and what is the voltage of the power supply to the drivers?

When it comes to testing I suggest you do one axis at a time. Many beginners try to get everything working and they have a number of faults but because
of the confusion of all the axes and switches they can't dial in on one fault let alone all of them. In fact if you disconnected the Y and Z motors and
just got the X axis working to start with would it matter? Whats the bet that once you get the X axis working you'll understand the tricks involved and
can set the other axes up in a snip.

With the same mindset I would disable all the limit and home switches as well. You need to have the Estop working and close at hand so you can stop
a runaway axis while you are setting up and learning but the extra confusion of all those switches doesn't help you, in fact can bugger you up bigtime!

Craig
My wife left with my best friend...
     and I miss him!

Offline Dax

*
  •  19 19
    • View Profile
Re: Stepper motors
« Reply #11 on: October 14, 2017, 07:44:33 AM »
Hi well I tried all the settings I could when I tried to auto step the machine in settings it failed twice on the x and once on the z. finally set up all working ran a test piece without the router or extraction heard the motor fail on the x at 30% through only a small stall but enough. I have been unable to find out what specs my motors are but they are mde by motionking 23hs1404 the control cards are CW 5045 are currently set to 1.5a at half current (wondering if this should be more) the motors are 100mm?! card set to 8 steps. hope this helps.
Re: Stepper motors
« Reply #12 on: October 14, 2017, 08:24:47 AM »
Hi,
best guess is they are 23 size steppers, you say they are 100 mm long then my guess is that they are 4.2A units 250 N.cm rated. That works out to
325 oz.in, plenty good. The drives are capable of up to 50V. Do you have a multimeter? Can you measure the power supply voltage or can you
see some specs written on it. For best speed you want it as high as you can go, if its 24V or less then its a joke and should be swapped with one with
36V or better 48V. Best to allow for full current for all motors simultaneously so rated current ideally 12.6A or better.

You should change the current switches so that the current is closer to rated.
SW1 ON
SW2 OFF
SW3 OFF
Should result in current of 4.2A. In practice the steppers may get too hot and you'll have to consider backing the current off. Dropping it to 1.5A is
too extreme.

The full/half current switch refers to the idle current, it can be left as is.

Craig
My wife left with my best friend...
     and I miss him!
Re: Stepper motors
« Reply #13 on: October 14, 2017, 08:33:30 AM »
Hi,
the only other possibility I can think of is that the PC is getting interrupted. We haven't established as fact that it is a parallel port machine.
What cable connects the PC to the controller/break out board? If it is parallel port then its entirely probable that the PC will 'stutter' and
cause little stalls and other funny behaviour. Its unfortunate but its the reality of parallel ports. In the first instance turn off ALL and EVERY
program you can.

What sort of PC is it? What version of Windows is it running? Is it 32 or 64 bit?

Craig
My wife left with my best friend...
     and I miss him!

Offline Dax

*
  •  19 19
    • View Profile
Re: Stepper motors
« Reply #14 on: October 14, 2017, 08:41:24 AM »
PSU is 8.5amp at 50v a great big round one.  I have just found a piece of paper (came with the machine) written on the back in pencil are the dip switches, looks like they are all wrong paper says
123 off =1.5a with a tick next to it
sw4 = on Half current
Micro step 5678
5=off
6=off
7=on
8=off
to me it looks completely transposed could this be it....
« Last Edit: October 14, 2017, 08:46:35 AM by Dax »
Re: Stepper motors
« Reply #15 on: October 14, 2017, 08:49:32 AM »
Hi,
kool that power supply sounds close to spot on.

I think you are right...all those switch positions sound wrong. I found the driver manual:
http://cnc4you.co.uk/resources/CW5045.pdf

Craig
My wife left with my best friend...
     and I miss him!

Offline Dax

*
  •  19 19
    • View Profile
Re: Stepper motors
« Reply #16 on: October 14, 2017, 08:53:41 AM »
right the way I see it is the power is set to 4.5a half power is off 568 are on and 7 is off that = 256 steps
so is 4.5a ok or too high?
microsteps should be 8 not 256 (would this cause my issue, expect it woulb tbh)
thanks for the manual craig
Re: Stepper motors
« Reply #17 on: October 14, 2017, 08:55:58 AM »
Hi,
the piece of paper doesn't match the picture. I would leave all switches 4-8 alone and reverse switches 2 and 3 only.

Craig
My wife left with my best friend...
     and I miss him!

Offline Dax

*
  •  19 19
    • View Profile
Re: Stepper motors
« Reply #18 on: October 14, 2017, 09:02:58 AM »
just found motor rated at 4.2amp so is 4.5amp ok? 123 all on
Re: Stepper motors
« Reply #19 on: October 14, 2017, 09:05:03 AM »
Hi,
can you double check that the motors are 100mm long? If they are then I'm fairly confident that they are 4.2A units.
If they're not then they could get hot and/or blow up. Given that I live I New Zealand I figure that I'm far enuf away you couldn't
hurt me anyway!

Until and unless you can get these motors sorted you machine is useless right? So are you going to take a chance to get them to work?

Craig
My wife left with my best friend...
     and I miss him!