Go Down

Topic: KP4M-203 stepper (Read 136 times) previous topic - next topic

phil77560

Hi,
As anyone ever used the KP4M-203 stepper with arduino ?
How could I connect it ?
Could I use the 28DYJ48 's controler ?
The KP got 4 wires ....the 28DY got 5 ...
Any help welcome
Thanks a lot

Robin2

If it has 4 wires it is probably a bipolar stepper so a unipolar driver would not be appropriate.

Post a link to the datasheet for your motor.

Read stepper motor basics.

...R

phil77560

Here is the doc : here
thanks to help me

Robin2

#3
Apr 14, 2015, 09:39 pm Last Edit: Apr 14, 2015, 09:41 pm by Robin2
That is a bipolar motor. Use a Sparkfun Easydriver, or a BigEasydriver or a Pololu A4988 to control it.

I'm guessing that Stromstarke means current so that your driver board should have the current limit set at 0.15Amps.

...R

MarkT

It appears to be a high-impedance bipolar motor, so can be driven from a motor shield,
each winding must go to one of the H-bridges.

Alternatively you can run it from a chopper drive, but the high resistance means
you'll need at least 18V supply and it won't perform very well.  Generally you'd
pair a low resistance motor with a chopper drive and get high speed performance.

For high impedance motors its easiest to use a unipolar motor and something like
a ULN2803 which is v. cheap.
[ I won't respond to messages, use the forum please ]

phil77560

Ok, I'll look for this....
Thanks a lot for your precious help
 ;)

Robin2

Alternatively you can run it from a chopper drive, but the high resistance means
you'll need at least 18V supply and it won't perform very well.  Generally you'd
pair a low resistance motor with a chopper drive and get high speed performance.
Please may I ask a question ...

I infer from this that you are saying that a higher voltage is needed when a "chopper" drive is used compared with when a h-bridge driver is used. If that is what you are implying I don't understand why. It seems to me the electrical characteristics of the motor won't change just because it is connected to a different driver.

...R

MarkT

The chopper drive needs some voltage overhead above the winding voltage drop
(usually a LOT of overhead is used, 10 to 50 times as much for top performance).

You need to understand back EMF.  A stepper motor generates large back EMF at
quite modest speeds due to the large number of poles (typically 100 poles), so you
need high voltage to overcome this, or it just won't turn very fast.  The high voltage also
overcomes the inductive back-EMF from the windings needed to switch the current
rapidly (which needs to be done because of the large number of poles....).

However what you don't want is a large voltage across the winding resistance, just
to balance out back EMF.  Thus you current-drive, since then you can control IR
losses independently of voltage.

Your typical stepper has 50 pole pairs, typical DC motor 1 pole pair, thus with
voltage drive you could compare a 6000 rpm DC motor is roughly like a stepper
at 120rpm.  With current drive you can make that same stepper do several 1000 rpm.

You top-flight high performance big stepper motor on a large CNC machine might be
0.5 ohm windings at 5A, driven from a chopper drive powered from 100V DC.  2.5V
goes to the winding resistance, the rest overcomes back-EMF and makes the thing
really fast and powerful (hundreds of watts mechanical, despite only 12W dissipated
in the windings).  Drive the same motor from 2.5V and you'd be lucky to see 60rpm!
[ I won't respond to messages, use the forum please ]

Robin2

You top-flight high performance big stepper motor on a large CNC machine might be
0.5 ohm windings at 5A, driven from a chopper drive powered from 100V DC.  2.5V
goes to the winding resistance, the rest overcomes back-EMF and makes the thing
really fast and powerful (hundreds of watts mechanical, despite only 12W dissipated
in the windings).  Drive the same motor from 2.5V and you'd be lucky to see 60rpm!
This part I understand.

But, by and large, Arduino users drive motors with 12v, 24v or maybe 36v rather than 100v.

If you are implying that a bigger gap between the nominal voltage and the power supply voltage is better, I can sort-of understand that - i.e. driving a 2.5v motor with 24v compared to driving a 12v motor with 24v.

But I asked the question because I thought you were telling the OP in Reply #4 that there would be little or no advantage using a chopper drive instead of a h-bridge for a higher voltage stepper motor. My perception is that a chopper drive (with a suitable power supply) would always be best.

If I am wrong I would like to know.

Thanks, Mark

...R

Go Up
 


Please enter a valid email to subscribe

Confirm your email address

We need to confirm your email address.
To complete the subscription, please click the link in the email we just sent you.

Thank you for subscribing!

Arduino
via Egeo 16
Torino, 10131
Italy