Author Topic: Power supply for Nema 23 Stepper ? (Read 11973 times)

Buell · « **on:** November 10, 2018, 08:02:27 AM »

Hi all, Im trying to work out which power supply to Buy for my Build I have a Nema 23 rated at 2.8amps. Now i may Need to get a bigger one if its not powerful enough.. with that in mind I may go to the 4amp version.

So im really confused about the whole electronics rating etc. So thought it would be simple...the motor so Im lead to believe is 12v dc a little bit like my car battery and all components within the Auto vehicle. with that in mind my head says look for a 12v 4amp supply obviously 240v as i live in uk. simple !

So i get the 220v-110 supply power description but then it gets very weird FOR ME !...the output varies from 5v 12v-40v the list is endless , with varying amperage inc.. and then you have regulated unregulated. I realise why im not an electrician ! although I do try to understand it.

Maybe someone could explain very simply the basics and whats important and whats not ? And maybe tell me whats the supply I need ?

In basic terms im trying to get a simple power supply for a power feed for my mill.
Much appreciated help.

Chuck in E. TN · « **Reply #1 on:** November 10, 2018, 08:34:25 AM »

Buell, unless your going to convert to CNC on your mill, you don't need a stepper. A simple DC motor, like a windshield wiper motor, or maybe a motor salvaged from a cordless drill will be sufficient. The motor can be speed controlled by a cheap Chinese PWM controller, available on E-Bay. For a power supply, anything up to 30 volts is good on a 12v motor. The PWM(pulse width modulation) controller sends pulses of DC voltage to the motor, the pulse with being modulated. The wider the pulse, the faster the motor goes.
I'm not saying a power feed can't be made using a stepper, but if you're not going to cnc, simple is better. Oh, the same applies to steppers pertaining to power. Steppers are current driven, and use a stepper driver to control direction and amount of travel.
I built a X axis power feed for my X2 mill from a gear motor, a PWM speed control and an 18vdc laptop power supply. On the other hand, I built an Arduino based controller to drive my rotary table that uses a stepper for accurate positioning. It so uses a laptop power supply.

Buell · « **Reply #2 on:** November 10, 2018, 09:56:17 AM »

Thanks for the reply...You say "Anything up to 30v is good on a 12V motor " To me that just sounds crazy ..makes no sense. My brain says thats like Diesel in a petrol car is ok ! sorry probably not a great Analogy but best Ive got ! 12v to 30v is almost 200% difference Am i missing something ? And why just 30v why not 40v or say 60v !

I will be using a stepper with a Driver unit as I have just received them ..im trying to understand and tinker with this to get used to it before I try a CNC or the like.

awemawson · « **Reply #3 on:** November 10, 2018, 10:39:46 AM »

Stepper drivers chop the output to control the current through the windings. It's the current that gives you the torque and the voltages helps overcoming their inductance.

So it's not like a conventional motor where a 12 volt motor needs a 12 volt supply. My CNC Plasma table steppers are driven from a 68 volt supply but the motors are rated at only a few volts per phase.

. . . it's all in the pulses

seadog · « **Reply #4 on:** November 10, 2018, 11:56:10 AM »

" 12v to 30v is almost 200% difference"

Try 250%

John Swift · « **Reply #5 on:** November 10, 2018, 12:48:29 PM »

a rule of thumb from Geckodrive.com

" The power supply voltage is determined by multiplying the square root of the motor’s inductance by 32, as in the example below for a 2mH rated motor:

32 * (√2) = 45VDC "

the faster you need to step the motor the shorter the time for the motor current has to build up to the current you have set the drive to

the higher the motors inductance the longer it takes for the current to build up

by using a higher supply voltage you can force the motor current to build up to the set value in a shorter time

that's why your going to be disappointed with some of the Chinese cnc kits that have a 24V supply and motors with a very high inductance , about 8 mH or more with some kits

8mH stepper motors will require the driver to be powered by a 90V supply unless you want your machine to run at a snails pace

John

kayzed1 · « **Reply #6 on:** November 10, 2018, 01:48:48 PM »

Thank you John, i just found out why my rotary table runs at around 3 inch per hour

I need a good stepper motor...
Lyn.

Chuck in E. TN · « **Reply #7 on:** November 10, 2018, 02:37:17 PM »

Using a higher voltage dc supply on a dc motor by way of a pwm control module is the same as using a higher voltage supply on a stepper by way of a stepper driver. By using PWM, you are not applying the larger voltage constantly, but in pulses. I know it seems to defy logic, do some research.
Google is your friend.

Buell · « **Reply #8 on:** November 11, 2018, 12:22:43 PM »

Quote from: John Swift on November 10, 2018, 12:48:29 PM

a rule of thumb from Geckodrive.com

" The power supply voltage is determined by multiplying the square root of the motor’s inductance by 32, as in the example below for a 2mH rated motor:

32 * (√2) = 45VDC "

the faster you need to step the motor the shorter the time for the motor current has to build up to the current you have set the drive to

the higher the motors inductance the longer it takes for the current to build up

by using a higher supply voltage you can force the motor current to build up to the set value in a shorter time

that's why your going to be disappointed with some of the Chinese cnc kits that have a 24V supply and motors with a very high inductance , about 8 mH or more with some kits

8mH stepper motors will require the driver to be powered by a 90V supply unless you want your machine to run at a snails pace

John

Thanks for this I have just checked the Inductance on the Box says "Phase Inductance at 1khz typical is 2.5

so If my poor maths is correct that is 46.16v

With that in Mind ...I just need a Medium speed to traverse quickly when Not cutting and a Very slow speed for when it is cutting. Does that alter anything ?

Also just noticed the driver I bought of Fleecebay is rated at Dc 9-40vdc at max 3.5amps and 4.0 at Pk Current which i guess is at Peak current ?

Please excuse my ignorance within electronics as I know Very little and am trying my hardest to grasp a small slither of what many folk know lots.

Buell · « **Reply #9 on:** November 11, 2018, 12:41:54 PM »

Clearly I shouldn't Go over 40vdc at 4amps as thats all the Driver could handle ?

ddmckee54 · « **Reply #10 on:** November 14, 2018, 11:07:04 AM »

That's right, it's like the weakest link in a chain.

Look at the voltage ratings of all the equipment. Whatever has the LOWEST maximum rating will be the highest voltage that you use for that entire system. You can use lower voltage, within reason, and the system will still run - it will just run a little slower.

Don

Buell · « **Reply #11 on:** November 29, 2018, 05:05:39 PM »

Ok so got a few bits but super struggling with the wiring side made someone could clear the fog..all lights up nothing has gone bang ! but nothing moves or shakes or rattles yet...but locked solid when the power is on. Help

philf · « **Reply #12 on:** November 29, 2018, 05:46:54 PM »

Hi Buell,

Excuse the crap drawing (I'm not good at drawing with a mouse) but I think you need to connect it something like this:

I would connect the Direction, Enable and Pulse wires to -ve but then you need to common all the +5V terminals together and connect them to 5V. The inputs are usually opto-isolated and you need connections to both -ve & +ve.

Phil.

Buell · « **Reply #13 on:** November 29, 2018, 06:04:07 PM »

Thanks for that...finally found something online...turns out its ...

PUL+DIR+ ENA+ all together to the last terminal on the controller ..have no idea what that is as its in chinesium.
PUL - to CLK
DIR- To DIR
ENA- to En

so one other question if I had made the worst dogs dinner out of this , is there any damage i could do ? other than mains in and 24v to the wrong terminals ?

Just the beginning for me doing this kind of stuff !
Thanks for the reply this thing works !

John Swift · « **Reply #14 on:** November 29, 2018, 06:08:10 PM »

Buell

can you post a link to the instructions for the pulse / direction board ?

I expect the two terminals labled in Chinese are +5V out from the regulator IC
and the common 0v to the pulse , direction & enable outputs

for your initial test just connect the stepper driver -pulse to the negative supply terminal
and + pulse to the pulse board pulse output

PS
do you have a multimeter ?

with the meter set to ohms
you should be able to test for continuity between the negative supply terminal and the two terminals labeled in Chinese
to find out which is the 0V and which is the +5V out

Buell · « **Reply #15 on:** November 29, 2018, 06:42:07 PM »

Got it going heres a vid

Hope its ok to post here ?

Buell · « **Reply #16 on:** November 29, 2018, 06:47:57 PM »

This is what I ended up with as a visual just In case it didn't make sense. Well it doesn't to me !

Buell · « **Reply #17 on:** November 29, 2018, 06:59:57 PM »

One draw back to this wiring....It doesn't Lock The motor !! Any ideas ? I would need it to lock to stop it from moving In the mill.

philf · « **Reply #18 on:** November 30, 2018, 02:35:56 AM »

Buell,

You'd need to keep the enable input grounded to keep the motor powered to hold it. If your control board doesn't do that just put a switch in the enable line to switch the input to your driver from the control board to 0v.

Phil.

Buell · « **Reply #19 on:** November 30, 2018, 04:55:13 AM »

Quote from: philf on November 30, 2018, 02:35:56 AM

Buell,

You'd need to keep the enable input grounded to keep the motor powered to hold it. If your control board doesn't do that just put a switch in the enable line to switch the input to your driver from the control board to 0v.

Phil.

Exactly how do i do that ? On the power supply the + output goes to the GND on the stepper driver (Just that doesn't make sense to me , Ground has always been Earth to me )

philf · « **Reply #20 on:** November 30, 2018, 05:08:41 AM »

Hi Buell,

Why does the +ve from your power supply go to GND on your driver? I'm sure it shouldn't.

(Just to clarify This is to enable the enable (excuse the pun) if the control board enable drops out whilst the motor is not turning.) I can't do a sketch at the moment but you'd want a single pole changeover switch with the common connected to the input of your driver, one other connection to the Enable connection on your control board and the other to the common ground on the 5v supply.

Phil.

Buell · « **Reply #21 on:** November 30, 2018, 01:38:04 PM »

No reason other than I copied it from somewhere ! .. Clearly if you think its wrong i will change it !

Buell · « **Reply #22 on:** November 30, 2018, 01:44:15 PM »

This is how I made a Start..but then realised that the controller thing was not the same ! but seemed a good place to start !

ddmckee54 · « **Reply #23 on:** November 30, 2018, 02:13:42 PM »

Any chance that you could supply us with the manufacturer and model number of the boards that you are using?

I'd hate to see you unintentionally let the magic smoke out of your boards, and with the part numbers we might be able to find the manuals on-line and help you decode their "Chinglish".

From what I can see it looks like your set-up should work, you've got it turning so it's sort of working. But the people that write the directions are not exactly consistent/knowledgeable regarding their subject. Sometimes it requires a healthy imagination and a secret decoder ring to make any sense of their manuals.

This could be something as simple as your stepper driver board is looking for a "HIGH" level pulse on its' inputs, while your pulse/direction board is supplying a "LOW" level pulse.

Don

John Swift · « **Reply #24 on:** November 30, 2018, 03:33:52 PM »

looking at the diagram in post22
it looks like they got the stepper drivers supply wires crossed !
fortunately you wired plus to plus and negative to negative even though you using black as positive & brown as negative looks odd

and should look like the original diagram with correction

if the direction & enable switches toggle between +5V and ground/0V

you can try the second version alternative wiring diagram with 0V connected to the step , direction & enable negative terminals

mc · « **Reply #25 on:** November 30, 2018, 03:41:04 PM »

Back to basics. Think of each control input to the driver as a little light bulb (they are actually an LED, just a fully enclosed one), that need both a positive and negative to light up.
The ENA, is your Enable. You need to apply power to this so the driver starts outputting power to the motor. The basic test for this, is with the main power connected to the driver, and the ENA powered, the motor should lock and remain stationary.
The DIR, is Direction. As the name says, it controls what direction your motor turns. Unpowered, the motor goes one direction, powered the motor should go the opposite direction.
The PUL, is Pulse, or more commonly referred to as Step. Each time this input gets switched on, the driver moves the motor one micro step (this depends on how the jumpers on the driver are set. On the driver you have, this could be 1 full motor step (1.8deg) down to 1/32 step (theoretically 0.5625deg or 3.375seconds).

To have your motor continually locked, you need to power the Enable. How you achieve this will depend on how you can get a continuous 5V. If you power up the control board you have without switching it on, is there 5V available at any of the terminals?
Looking at the photo, it's using a bog standard 5V regulator, so you should be able to use the input ground wire as the 0V, then probe the rest of the unknown terminals to see if any have continuous 5V. If there is no 5V, check again with the board switched on. It won't help you, but it'll at least establish what the unmarked terminals do.

I would hazard a guess, the two terminals marked in chinese are a 0V and a 5V connection.

If the board only outputs 5V when switched on, then I'll suggest other options.

And for those mentioning switching positives/negatives (other than the obvious diagram error of the main supply wires from the PSU to the driver being wrong - if you had done this, the driver would be a paperweight as soon as you powered it up) , and it making a difference, for the purpose of what you're trying to achieve here, it'll make no difference. Pulse timing and switching polarity does make a difference in CNC, however here you simply want to get the motor to lock/spin, so step/dir timing/polarity can be ignored.

Buell · « **Reply #26 on:** November 30, 2018, 04:36:24 PM »

Ok so just to clarify the diagram above for the controller is THE WRONG ONE ! it was just something I started with.

The unit im using is the One in this picture...

It has the following connections None of which I have any idea what they do or how they work !

EN>>>>DIR>>>>>CLK>>>>Chinese writing>>>>>>>>Chinese Writing.

I have wired as Follows and it works perfectly !!! Only issue is that I would like IT to LOCK WHEN NOT BEING USED.

EN>ENA-

DIR>DIR-

CLK>PUL-

Last Chinese writing>DIR+5V Which has a link to pul+5V and a link to ENA+5v

excuse my lack of knowledge in this Im surprised it hasn't gone up in smoke yet ! I know nothing about this wiring i just wanted the motor to turn and lock in two directions with a decent amount of torque. As i say if you see the video it works just doesn't lock up when not used or off. Which will be helpful as i intend to use on a mill. Many thanks the item is of aliexpress and ebay.

This is what the mnf says.... thanks for all the help maybe this isn't possible ?

5613
Stepper Motor Driver Controller PWM Pulse Signal Generator Speed Control 12V-24V

Description :
1 this module is a pulse generation module, supply the control signal to stepper driver.
To control the stepper motor, it must be equipped with a drive.
2 this simple controller + stepper motor + stepper motor + DC power supply can be composed of a simple set of control platform.
3 the controller has high 5.4k-160khz, middle 540-16.6khz, low 80-2.4khz total of 3 kinds of low frequency signal can be used to select the jumper.
4 can produce pulse signal, can also produce PWM signal, can choose the jumper.
5 the frequency of measurement: PUL and common cathode end.

Different stepper driver may mark different name

EN=ENA=FREE Enable
PUL=PULS=CLK Pulse
DIR=CW=CWW Direction

Common anode Connection method (B)

EN+ PUL+ DIR+ connect together to com+。
EN- connect EN
PUL- connect CLK
DIR- connect DIR

Common cathode Connection method (B)
EN- PUL- DIR- connect together to com-。
EN+ connect EN
PUL+ connect CLK
DIR+ connect DIR

Buell · « **Reply #27 on:** November 30, 2018, 04:47:59 PM »

Quote from: mc on November 30, 2018, 03:41:04 PM

Back to basics. Think of each control input to the driver as a little light bulb (they are actually an LED, just a fully enclosed one), that need both a positive and negative to light up.
The ENA, is your Enable. You need to apply power to this so the driver starts outputting power to the motor. The basic test for this, is with the main power connected to the driver, and the ENA powered, the motor should lock and remain stationary.
The DIR, is Direction. As the name says, it controls what direction your motor turns. Unpowered, the motor goes one direction, powered the motor should go the opposite direction.
The PUL, is Pulse, or more commonly referred to as Step. Each time this input gets switched on, the driver moves the motor one micro step (this depends on how the jumpers on the driver are set. On the driver you have, this could be 1 full motor step (1.8deg) down to 1/32 step (theoretically 0.5625deg or 3.375seconds).

To have your motor continually locked, you need to power the Enable. How you achieve this will depend on how you can get a continuous 5V. If you power up the control board you have without switching it on, is there 5V available at any of the terminals?
Looking at the photo, it's using a bog standard 5V regulator, so you should be able to use the input ground wire as the 0V, then probe the rest of the unknown terminals to see if any have continuous 5V. If there is no 5V, check again with the board switched on. It won't help you, but it'll at least establish what the unmarked terminals do.

I would hazard a guess, the two terminals marked in chinese are a 0V and a 5V connection.

If the board only outputs 5V when switched on, then I'll suggest other options.

And for those mentioning switching positives/negatives (other than the obvious diagram error of the main supply wires from the PSU to the driver being wrong - if you had done this, the driver would be a paperweight as soon as you powered it up) , and it making a difference, for the purpose of what you're trying to achieve here, it'll make no difference. Pulse timing and switching polarity does make a difference in CNC, however here you simply want to get the motor to lock/spin, so step/dir timing/polarity can be ignored.

This is a good start thank you ..Ok so with the controller off...but power and it lite up the last output has a permanent 5v its the one im using that goes to ..DIR+5v that links to ENA + 5V and also goes to Pul+..
Now what ?

mc · « **Reply #28 on:** November 30, 2018, 05:00:25 PM »

Quote from: Buell on November 30, 2018, 04:47:59 PM

This is a good start thank you ..Ok so with the controller off...but power and it lite up the last output has a permanent 5v its the one im using that goes to ..DIR+5v that links to ENA + 5V and also goes to Pul+..
Now what ?

I've just realised the controller has a ENA output, which you are using, but don't want to be as it'll be getting controlled by the on/off switch.
In which case, moving the wire you have connected to the ENA output over to a 0V terminal (I'd guess the other mystery Chinese terminal will be 0V, but best check first), should mean the driver is enabled and the motor locked with everything powered up, but the controller switched off.

Switching on the controller should then allow you to control the motor, then switching off lock the motor again.

Buell · « **Reply #29 on:** November 30, 2018, 05:13:22 PM »

Checked 0 volts on the terminal next to it so just shift the wire to that terminal and leave the other end at the driver thats has connections on ENA+ DIR+ AND PUL +?

mc · « **Reply #30 on:** November 30, 2018, 05:15:30 PM »

Quote from: Buell on November 30, 2018, 05:13:22 PM

Checked 0 volts on the terminal next to it so just shift the wire to that terminal and leave the other end at the driver thats has connections on ENA+ DIR+ AND PUL +?

Yes. That way the ENA on the driver should have a permanent connection to 0V and 5V.

Buell · « **Reply #31 on:** November 30, 2018, 05:25:30 PM »

Nothing Now !

Buell · « **Reply #32 on:** November 30, 2018, 05:27:17 PM »

locks up with power ON and Off but no movement

mc · « **Reply #33 on:** November 30, 2018, 05:32:49 PM »

Just need to clarify this.

Did you move the wire that was connected to the ENA terminal on the controller, or a different wire?

Your + terminals on the driver, should still be connected to the outer Chinese writing terminal (this being your common 5V supply).
You then want to connect the ENA- wire from the driver to the inner Chinese writing terminal (which should be your common 0V/Gnd connection)

I suspect we've got out wires crossed, and you've moved the + terminals to 0V and is why you're now getting nothing.

Buell · « **Reply #34 on:** November 30, 2018, 05:36:33 PM »

Your prob correct ! The ENA- at the moment goes to another terminal in the controller marked EN....IM guessing I dont need this one !

Buell · « **Reply #35 on:** November 30, 2018, 05:48:11 PM »

No doesn't want to Work for me

mc · « **Reply #36 on:** November 30, 2018, 06:06:42 PM »

Quote from: Buell on November 30, 2018, 05:36:33 PM

Your prob correct ! The ENA- at the moment goes to another terminal in the controller marked EN....IM guessing I dont need this one !

That is the wire you need to connect to 0V.

With power connected (and the controller still switched off), measuring across the ENA + and - terminals on the driver, you should get 5V.

Buell · « **Reply #37 on:** November 30, 2018, 06:28:34 PM »

On the driver if i Measure ENA _ AND ENA+ i get 3.45v IF I measure ground on the driver and the ENA + i get 5 volts.

This is what i have and this is what I tried

mc · « **Reply #38 on:** November 30, 2018, 06:35:27 PM »

That must not be a 0V terminal on the controller then, and it must be floating up under load for some reason. The driver inputs must need nearer to 5v to activate properly.

Try wiring the ENA- terminal directly to the Gnd/0V at the power supply (you could try bridging it across to the main supply Gnd at the driver, but that could potentially cause problems, and I wouldn't recommend it other than for a quick test).

Buell · « **Reply #39 on:** November 30, 2018, 06:48:57 PM »

Thought It was too good to be true... Simple controller power supply etc...Looks like I will need a bigger pair of vice grips now !

John Swift · « **Reply #40 on:** November 30, 2018, 07:31:32 PM »

most stepper drivers enable input is a negative logic input

no input = drive enabled so the drive workes with no connection to the enable or
both the - enable & + enable terminals at the same potential so no current passes through the opto-isolators LED

connecting a 5V supply across the - enable & + enable terminals will disable the drive !!!

in contrast the step input is a positive logic input and the motor will step on the positive going transition
of the step input

with many Chinese TB6560 or TB6064 stepper driver boards have a simple current reduction circuit that is intended to reduce the motor current when the drive is idle
at best the circuit only works correctly if the step pulse is positive going
(active high with the negative pulse input connected to input common GND
due to a design error on some TB6560 boards the current reduction only works with some of the micro step settings)

John

Buell · « **Reply #41 on:** December 01, 2018, 05:39:18 AM »

Quote from: John Swift on November 29, 2018, 06:08:10 PM

Buell

can you post a link to the instructions for the pulse / direction board ?

I expect the two terminals labled in Chinese are +5V out from the regulator IC
and the common 0v to the pulse , direction & enable outputs

for your initial test just connect the stepper driver -pulse to the negative supply terminal
and + pulse to the pulse board pulse output

PS
do you have a multimeter ?

with the meter set to ohms
you should be able to test for continuity between the negative supply terminal and the two terminals labeled in Chinese
to find out which is the 0V and which is the +5V out

So I have taken It all apart and decided to start again just for my own sanity ! it looked messy and didn't feel I had given this a Fair chance . so results this morning,,,

with the Power from the power supply Now being Turned on and just the supply to the driver and the controller i have the Following as You stated..

24v to the controller....the EN on the controller with nothing attached in The OFF POSITION IS 5v however when the controller button is switched ON is 0v

DIR ON THE controller is 0v both on and off

CLK IS 2.2v on or off

Chinese writing is 0V on or off

and the Last terminal chinese writing is constant 5v on or off

so with just those connections when the power switch is on/off the motor is locked

Have I missed something ? will go back to your drawing and see if i can get this to work ! Wont give up yet....or am i flogging this horse !

Buell · « **Reply #42 on:** December 01, 2018, 08:45:11 AM »

In my heath robinson way I cut a simple toggle switch in on the wire marked ENA +5v on the driver to the other terminal DIR+5v... outcome is that it locks the motor which is great. However when the On/Off switch is activated ON the motor doesn't run in either direction and the lock is OFF Thus rendering the controller switch useless. However the toggle switch activates the lock in the Off position and activates the Motor in the other ! Is this where the saying " Forward one step back 2 steps comes from " I feel Im close but as they say " A miss is as good as a mile "

Still I haven't blown it up yet !

Buell · « **Reply #43 on:** December 01, 2018, 09:41:29 AM »

This is as Good as it gets ...The controller has a CLK that was going to PUL- I put an Inline Switch there and It WORKS... When I did it before I assumed it was wrong because the light on the Board was Off and thought It was back to front..Theres a Chap who goes by the way Of NSA on youtube he kindly answered the question and Advised and Seems ok. Think i will put a different type of switch now i know it works . Thanks to all that helped finally got there.

John Swift · « **Reply #44 on:** December 01, 2018, 11:10:58 AM »

without reverse engineering the pulse generator board I expect the DIR & EN terminals
are connected to on/off switches that either leave the terminals open circuit or connect them to
the negative supply

assuming the step terminal goes to the output pin of a NE555 IC
the pulse output is switching between 0V & +5V

If I am correct
this should work

Buell · « **Reply #45 on:** December 01, 2018, 12:39:05 PM »

This is what I have ended up with and it works Hope the loop over cables is evident !! Did my best!

Buell · « **Reply #46 on:** December 01, 2018, 12:42:55 PM »

With regards to cable sizes when I wire this for good can i just use standard .75 cable ? nema 23 motors.

awemawson · « **Reply #47 on:** December 01, 2018, 02:02:17 PM »

0.75 CSA copper cable is supposedly good for 14 amps

John Swift · « **Reply #48 on:** December 03, 2018, 01:05:42 PM »

Hi Buell

on the pulse generator board
I have now found out that the clock , direction & enable outputs have a 100ohm resistance in series

the enable and direction switches do switch between 0V & +5V

a NE555 IC is connected in its astable mode to run as an oscillator
the output pin 3 is conncted to the CLK terminal via a 100 ohm resistor

I have added the details to your diagram

the effect of these 100 ohm resistors is , depending on the current limiting resistors inside of the stepper driver

the pulse generator output will switch between +0.75V and + 4.25V or +1V and +4V
not the 0V to +5V I initially expected in an earlier post

inside various stepper drivers
the manuals indicate the input opto-isolators have a resistor between 200 & 300 ohms to limit the LED current to a safe value with a 5V input

John

diagram re saved after correcting typo

Buell · « **Reply #49 on:** December 04, 2018, 04:32:28 PM »

Quote from: John Swift on December 03, 2018, 01:05:42 PM

Hi Buell

on the pulse generator board
I have now found out that the clock , direction & enable outputs have a 100ohm resistance in series

the enable and direction switches do switch between 0V & +5V

a NE555 IC is connected in its astable mode to run as an oscillator
the output pin 3 is conncted to the CLK terminal via a 100 ohm resistor

I have added the details to your diagram

the effect of these 100 ohm resistors is , depending on the current limiting resistors inside of the stepper driver

the pulse generator output will switch between +0.75V and + 4.25V or +1V and +4V
not the 0V to +5V I initially expected in an earlier post

inside various stepper drivers
the manuals indicate the input opto-isolators have a resistor between 200 & 300 ohms to limit the LED current to a safe value with a 5V input

John

diagram re saved after correcting typo

THANKS VERY MUCH FOR THIS ....BUT WHAT DOES IT MEAN TO SOMEONE THAT DOESNT SPEAK A WORD OF ELECTRONICENGLISH !

or just layman terms. You will have to forgive me...looking at that reminded me of so many lessons at school where I couldn't understand what the hell the teacher was talking about ! But i do appreciate the effort you made to find out the details so thank you again.

mc · « **Reply #50 on:** December 05, 2018, 05:16:17 AM »

Quote from: Buell on December 04, 2018, 04:32:28 PM

THANKS VERY MUCH FOR THIS ....BUT WHAT DOES IT MEAN TO SOMEONE THAT DOESNT SPEAK A WORD OF ELECTRONICENGLISH !

or just layman terms. You will have to forgive me...looking at that reminded me of so many lessons at school where I couldn't understand what the hell the teacher was talking about ! But i do appreciate the effort you made to find out the details so thank you again.

In layman's terms, you can ignore it. John just likes to reverse engineer these kind of things, and post the info for reference.

All you really need to know is how to wire things up, which is why I'll try to only post the basic information needed to get things working, as it can be too easy to confuse people with information that's not needed.

And I apologise for taking you the wrong direction with the enable circuit. I keep forgetting lots of stepper drives default to enabled, as everything I've done lately requires an enable to work.

Will_D · « **Reply #51 on:** December 07, 2018, 04:40:08 AM »

With regards to the photo in post #12:

Are the Blue and Yellow ferules crimped onto the wire or are they solder or are they just slipped on and then the connector screw does the crimping. I am just about to do about 50 or 60 of these joints!

mc · « **Reply #52 on:** December 07, 2018, 06:06:06 AM »

Quote from: Will_D on December 07, 2018, 04:40:08 AM

With regards to the photo in post #12:

Are the Blue and Yellow ferules crimped onto the wire or are they solder or are they just slipped on and then the connector screw does the crimping. I am just about to do about 50 or 60 of these joints!

They're bootlace ferrules/cord end terminals depending on where you are.
You get proper crimping pliers that crimp them square, but you can just nip them up with some side cutters, then rely on the terminal to crimp them, however that often results in them flattened too much so you struggle to get them into terminals.
A set of crimping pliers isn't that expensive (just checked and they're about £13 on eBay just now), and they make using bootlaces far easier.

John Swift · « **Reply #53 on:** December 07, 2018, 04:54:23 PM »

Hi Buell

In the absence of instructions for the pulse generator board

I have continued with the iterative process working out the details of the pulse generator details

Now I think I have corrected my problems connecting to the NET

here are two versions of the connections between the stepper driver and pulse generator board
using either the pulse generator common +5V or common 0V

while the diagrams don't show all the details of the board

they show enough to predict the state of the enable switch for the motor to run
and explain why the voltage across the stepper driver input terminals are closer to 4V instead of 5V due to the 100 ohm resistors on the pulse generator board
(thats if you measured the voltage across the pulse generator terminals before and after you connect them to the stepper driver inputs)

John

Will_D · « **Reply #54 on:** December 08, 2018, 07:00:27 AM »

Quote from: mc on December 07, 2018, 06:06:06 AM

They're bootlace ferrules/cord end terminals depending on where you are.
You get proper crimping pliers that crimp them square, but you can just nip them up with some side cutters, then rely on the terminal to crimp them, however that often results in them flattened too much so you struggle to get them into terminals.
A set of crimping pliers isn't that expensive (just checked and they're about £13 on eBay just now), and they make using bootlaces far easier.

Thats just the info I need, Many thanks MC

Johnny Bravo · « **Reply #55 on:** December 30, 2018, 09:01:44 AM »

This is a very interesting thread,with evidently some very experienced people responding. I don't want to hijack this thread,but I think my questions would be relevant. There seems to be a myriad of considerations when choosing stepper motors and drives. Unfortunately,for the newbie,some of these considerations are very difficult to quantify. So here is what I want to do....

I have a couple of Longs motors Nema 23 steppers, 425oz with an inductance of 6.8mH per phase.
Drivers can handle up to 50v.
Psu is 36v 9.6A
Ballscrews have a 5mm pitch.
Now, lf I use that formula used earlier in the thread,these motors "should" be fed about 80v... More than the drivers can handle. However....
I want to use it with a laser welder. My feed rate will be dictated by the frequency at which I can fire the laser,in my case, 40 times a minute. Assuming a maximum spot diameter of 2 mm and 50% step over,this would give me a maximum feed rate of 40mm a minute. Obviously it's not like a lathe or a milling machine where the load goes up exponentially with regards to the depth of cut. The load will be constant. So.... I would still need to rapid occasionally, but it's not really a major issue. So, what would the best route to go be? Should I uprate the psu to 48v? Would I be better off say using a 3 to 1 reduction on the stepper motors? That would lend itself to a more compact set up, and more controllablility with finer work with say a 0,3mm spot weld and 50% step over.

Enlighten me !

philf · « **Reply #56 on:** December 30, 2018, 01:12:12 PM »

Johnny,

A 5mm pitch ballscrew directly driven from a half-stepping 200 ppr motor would give you a step of 0.0125mm. Is this not fine enough resolution for your welding job? A 1:3 reduction would obviously improve the resolution but if you don't need it why add it.

40mm/ minute is pretty pedestrian even by stepper standards. I'm sure your 36v supply will be more than OK at the low speeds (8 rpm) you're talking about with a decent margin for rapid moves.

Phil.

Johnny Bravo · « **Reply #57 on:** December 30, 2018, 02:12:12 PM »

Thanks Phil
If I had to add the extra 3-1 reduction,I could tuck the stepper motors in between the linear rails and make the whole set up more compact. The reason I asked, was, with such pedestrian feed rates, as you correctly point out, would it not be better to use the reduction and use full steps instead of micro stepping? Surely these stepper motors have a sweet spot where they run really nicely? I know with the servo motors on my cnc lathe,they are definitely happier not running at really low rpm. Surely here must be a certain rpm where they deliver maximum torque?

philf · « **Reply #58 on:** December 30, 2018, 03:49:04 PM »

Hi Johnny,

Running a stepper in full stepping mode can cause resonance problems. Half stepping or particularly microstepping helps to get around the problems.

On my CNC mill I use Nema 23 4N-m motors in 1/8 microstepping mode with no problems.

Phil.

Johnny Bravo · « **Reply #59 on:** December 30, 2018, 04:05:42 PM »

Having messed around with one of the stepper motors already, I have noticed 1/2 steps seemed smoother than full steps. Still think I will run the 3-1 toothed belt reduction, as it makes for a tidier install. Jury still out on running 48v psu or possibly swopping out Chinese stepper drivers for Geckodrives and running 80v. I have a nice toroidal transformer that would give me 80v dc with the necessary gubbins...

mc · « **Reply #60 on:** December 30, 2018, 06:25:08 PM »

At those speeds, I doubt you'd notice much difference with a higher voltage power supply. The only real benefit of a higher voltage would be during rapids, especially if you wanted high accelerations.

As Phil has mentioned microstepping does give smoother operation. Obviously there are limitations, but generally 8 is a good compromise between smoothness and needing high pulse rates. There are not really any benefits from using a higher microstep setting.

It's worth noting that microstepping does not really improve accuracy. While microstepping, the driver is essentially balancing the motor shaft between two magnets with varying levels of pushing/pulling. Stiction and forces in the system will also affect the position, so the position can only be guaranteed to within one step.

I'd say run with the 36VDC supply and see how you get on.
Given you're in the UK, I certainly wouldn't pay the extra for Gecko drives. Even cheaper Leadshine DM drives (or some of their copies) give as good performance. If you want the best performance possible, Leadshine EM drives are far more advanced than Gecko drives, and much cheaper! (EM806 retail is £106, and the G203V is £148 )

Johnny Bravo · « **Reply #61 on:** December 31, 2018, 06:11:19 AM »

Thanks for that.
Only reason I mentioned Geckodrives is I know where there are a couple I could have for little to no money...

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Author Topic: Power supply for Nema 23 Stepper ? (Read 11973 times)