Stepper motor control of X-Axis from MEW 199

[DaggersParticipant @daggers]

Hi All,

I have built the stepper motor driver as per MEW 199-200 for the X axis control of a milling machine, and all works as per the series.

My only problem is that the max revs of the motor is too low for my application.

The max rpm even with the fast button pressed is very,very low, just for ref I am using 8 micro steps which is 1600 steps per rev on the Arc Euro controller.

I am not an electronics expert but would it be possible to change the speed pot (470k) and the fast speed resistor (15k) to increase rpm?

Can anyone please give any advice?

Thanks in advance

John

[DaggersParticipant @daggers]

[DaggersParticipant @daggers]

Please note the MEW issues should be no.s 118 and 119, not as stated in first post.

john

[john swift 1Participant @johnswift1]

Hi John ,

 

looking at fig1 on page 42 MEW 119

with the 470K potentiometer set for maximum speed / minimum resistance

the frequency of the pulses from pin3 on the "555" timer IC will depend on the

value of R3 (1K) , R4 ( 310K) and capacitor C5 ( 0.01 uF)

depending on how fast you need the motor to step you could reduce R4 to 33K or even 3K3 if the stepper driver can cope

you can also set the driver to fewer microsteps

 

John

 

Edited By john swift 1 on 23/01/2013 18:43:08

[JAParticipant @ja]

John

A few years ago I built this table drive system. Like yours it worked well except for the slow table speed, maximum about 20 mm/min, and the failure of the LED to work. Last year I replaced the R4 resistor with a 47k resistor and the potentiometer with a 1M one. I did not change the stepper motor wiring on the basis that it was working (and I am ignorant about stepper motors). The table speed range is now 5mm/min to 112mm/min. My attempt at getting the LED to light-up has been less successful.

JA

[john swift 1Participant @johnswift1]

Hi JA ,

the the odds are the LED may of been damage by heat when you made solder connections to it

or its connected the wrong way round

the long wire is the Anode that connects to +5V supply via R1 (560 ohms)

the shorter wire next to the flat on the LED connects to the 0V supply

John

[DaggersParticipant @daggers]

thanks gents for the advice.

John,

I did try to decrease the step rate but this gave a jerk motion not smooth.

Will try you component changes, thanks.

JA,

my revs seem to be lower than your original build.

Will try your and John changes and see what happens.

Looks like yet another trip to Maplins.

All the best, will post the results.

John

[DaggersParticipant @daggers]

Gents,

just got back from Maplin and changed R4 to R33K which gives me the speed that I can live with.

Will now strip milling machine,clean and fit over the weekend.

Will report on final assembly/use.

Thanks to all.

John

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