cnc winder controller board

[-Elepro-]

ask me if you need help for wiring.... is this your first stepper adventure? don't be astonished if your motor give out SSSSShhhhhhhhhhhh .... it's chopper sound....

[David King]

It's fall in Oregon, the sound of black helicopters searching for a stray hemp plant can be heard resounding through the hills, I can handle a little chopper noise

[RedHouse]

Just got my drivers today.

[David King]

I plugged in my $1 ebay transformer and measured 26.4VAC at the output. I used the 13V tap and I connected that to terminal 1 and 6 (AC in) on the Dragon driver board.
I figured out what pairs of wires went together on my stepper motor. (Red+Yellow, Orange+Black) and connected those to terminals 2, 3, 4, & 5.
I then put a jumper between "step in" and "step out" (Terminals 1 & 2)
Another jumper to engage the internal oscillator in the high speed mode (Terminals 8 & 10).
I set the output amperage to 500ma (dip 1, 2 & 3 = "ON")
I plugged in the power and the motor started spinning very slowly, maybe 20 rpm.
I turned up the oscillator adjustment screw and was able to get the motor to spin up to about 200 RPM before it stalled out.
I reset the output current to 2A (all dips "off") and was able to get the motor up to about 800 rpm before it started sounding really bad and would stall out very easily. I'm no where near the maximum 17000Hz of the onboard oscillator. On "half step" setting the motor is very smooth but seems to not want to go as fast as "full step" (dip #6 off).

The motor doesn't seem to get hot. (It's a big Nema31, 225 oz/in one).
I'll see if the speed or torque goes up at 26V.
I'll try the smaller stepper motor one next.

[David King]

26V is the ticket!
I get the speed up over 1000RPM with no stalling. The oscillator sounds like a G note on the piano which is around 3200Hz I think or maybe 1/2 of that..?
I think I was in "half step" mode all along. "full step" isn't very happy at any speed.

No need to add belts or pulleys to this sucker yet.

You have to ramp the motor up to that speed -it won't start there on it's own.

The NEMA23 Motor is supposedly rated at 39 oz/in but I can't stall it with my fingers either and it seems perfectly happy at 1000 rpm as well.

Neither of the motors will self start-above about 250 rpm, to reverse the direction suddenly one would have to slow them down first? I don't suppose it takes very long to stop them and wind them up again but it isn't instantaneous.

[-Elepro-]

perfect....

26V is the ticket!
I get the speed up over 1000RPM with no stalling. The oscillator sounds like a G note on the piano which is around 3200Hz I think or maybe 1/2 of that..?
I think I was in "half step" mode all along.

yes.... i must change idea aboout stepper max rpm.... i've got 1000rpm too with my small nema23...

but.... how you measure speed?
if you have 3200hz you have

(3200/200)*60= 960RPM in full step
or
(3200/400)*60=480RPM in 1/2 step

"full step" isn't very happy at any speed

yes, in full step there are many problems of resonance.... for this no one use it..... my controller support only 1/2....

Neither of the motors will self start-above about 250 rpm, to reverse the direction suddenly one would have to slow them down first? I don't suppose it takes very long to stop them and wind them up again but it isn't instantaneous.

controller invert traverse rotation without ramp.... then 250rpm would be your max traverse speed..... it means max pitch of 0,25mm at 1000rpm (at main motor)... 40 tpl for 10mm height bobbin....
if you need greatest pitch you have to slow down main motor or mount pulley at traverse.... controller suppor 1:1 1:2 1:4 pulley ratio at traverse too...

[David King]

Elepro,
I was guessing at RPMs by listening to a piece of tape on the motor shaft slapping my thumb and then speeding up my metal lathe with tape on the chuck until I got roughly the same flapping speed and reading the spindle rpms off the Lathe VFD.

I was in half-step mode and the frequency must have been an octave higher so 6400Hz or so.

I was never sure if I had both motor coils in proper phase but I'm not sure if that even matters with a stepper.

The Dragon driver has a 20ms ramp-up but you can add a capacitor to lengthen it up to 400ms if you need to.

I thought the speed ramps-up could be built into the traverse software?

I'm not too concerned about limiting turn counts but we might want to change to a lower thread count on the traverse lead screw if speed is going to be a problem. I didn't actually verify the 250 maximum speed, it was just an educated guess...
Perhaps newer/better steppers with lower inertias can start faster?
2mm pitch is close to 13tpi which is a common enough thread and would be available in acme thread too.

I'm going to bolt one of these large steppers to the leadscrew on my lathe and use the driver as a speed/direction control...

[-Elepro-]

I was never sure if I had both motor coils in proper phase but I'm not sure if that even matters with a stepper.

if it run coils wiring is correct....

The Dragon driver has a 20ms ramp-up but you can add a capacitor to lengthen it up to 400ms if you need to.

I thought the speed ramps-up could be built into the traverse software?

traverse must invert rotation without aceleration-deceleration.... or you'll have more wire at ends of your pickup...

I'm not too concerned about limiting turn counts but we might want to change to a lower thread count on the traverse lead screw if speed is going to be a problem. I didn't actually verify the 250 maximum speed, it was just an educated guess...
Perhaps newer/better steppers with lower inertias can start faster?
2mm pitch is close to 13tpi which is a common enough thread and would be available in acme thread too.

for have a more fast traverse you can use 1:2 or 1:4 pulley..... or (i didn't think this) a 2mm or 4mm leadscrew..... it is same for controller...

1mm leadscrew with 1:2 pulley is same thing of 2mm leadscrew with 1:1

1mm leadscrew with 1:4 pulley is same thing of 4mm leadscrew with 1:1

[David King]

I did some more experimentation with the smaller stepper using the cw/ccw terminal and the stepper will reverse directions instantaneously up to a certain speed but it seems to be much slower than the starting from a stopped position which is about 500 RPM I think. When the direction change fails, the motor goes into spasms of fibrillation and won't move at all until you stop or slow the oscillator first.

I'll try the ramp-up capacitors and see if that makes much of a difference.

I don't think the wire will pile up on the ends if we leave a tiny gap between the ends of the bobbin. The wire will tend to fill any gaps without being guided exactly.

I think the next question is how exact the thread pitch needs to be for the winder to work correctly. If we go with the 13 tpi leadscrew thread (very common in the US). Do we really care if our winding pitch display is off by 2.3%? I can't imagine that would matter to my pickups provided the limit switches still work correctly.

[David King]

The coarser threads may be a problem since they imply a larger screw diameter, i.e. 14mm or 1/2" which is going to be heavier with much more inertia. I was hoping I could find "double start threads" with 1mm pitch but 2mm travel per revolution. The benefit would be a smaller diameter and less inertia. There's no doubt they exist but I can't find any. They can easily be cut on a lathe but there's a lot of expense associated with that and we would still need the nuts to fit.

I did find Nylon 6 threaded rod studs in 1/2-13 which would be light enough and very cheap

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[RedHouse]

if it run coils wiring is correct....



traverse must invert rotation without aceleration-deceleration.... or you'll have more wire at ends of your pickup...



for have a more fast traverse you can use 1:2 or 1:4 pulley..... or (i didn't think this) a 2mm or 4mm leadscrew..... it is same for controller...

1mm leadscrew with 1:2 pulley is same thing of 2mm leadscrew with 1:1

1mm leadscrew with 1:4 pulley is same thing of 4mm leadscrew with 1:1

Elepro, I don't think traverse speed is going to be an issue, but you really should have made the traverse programming able to accept an "ACME" theaded screw.

I got my motors and controllers test-wired and they check out so far in test mode, tonight I will work on the traverse attachment and hopefully it will all come together this weekend with your controller board in play.
(I'm busy Friday nights)

[David King]

The metric equivalent of acme thread is trapezoidal thread form. The smallest pitch available is 1.5mm but 2 mm is available -if we could source it.
There aren't any advantages in using either form in this application since the forces and need for accuracy are easily met by any thread form.

[RedHouse]

Elepro,

Hooked up the motors to the drivers and using the internal test-oscillator on the Dragon drivers (jumper "Step-out" to "Step-In") the motors run but have lower/upper weirdness and midband shakes.

(drivers are set to 1/2 step)

The driver boards have an on-board oscillator and a speed trim-pot so you can adjust/test the motor through a range of speeds. At both extremes of the trim pot (Slow and Fast) the motor whines weirdly and eventually stops turning as you approach the extreme end of the trimpot range.

There are a couple sweet spots in the low-mid RPM band and the mid-high band where the motors turn without whining or shaking.

When I say "whining" I'm not talking about the szszszsz sound the steppers make, but it's a definate audible tone whine sounds like the flyback transformer in a TV.

Of course it has the mid-band shakes I have read about but that is kind of expected.

The motors are hot to the touch, hot enough that if you touch them for a few seconds you will burn your finger, is this normal?

I did not get a Tach hooked up to the shaft yet but it looks like 600-RPM or less to my eye.



Then I hooked up your controller to the drivers and motors and tried to run through the options and settings.



Main stepper won't turn CW but will turn CCW in both OpMode and JogMode.

Traverse controls, motor and settings work well in both modes.

(both motors are hooked up the same and according to the Dragon spec sheet and Stepper spec sheet)

I need to get a tach hooked up but I'm suspitious the 600 RPM your board puts out is in the midband of the motors/controllers where they get the shakes, and somethings not right with the CW direction control from your board.

I want to see these motors/drivers/controllers working properly before I go to the trouble of building a machine.

I have a traverse slide worked out but will put it on hold until we get the bugs out of all this.

[David King]

Brad, steppers run hot, especially the small ones when you are pumping them with higher voltages and amperage. It's kind of like a class A audio amp -you're dissipating the full driver wattage (about 60W) in the motor coils all the time whether the motor is turning out or not. I think anything over 180ºF is probably bad over the long term- that's pretty hot. My smaller ones got up to 115º after an hour, the big ones were barely warm. I'm thinking bigger is better on the shakiness/resonance, mid-band fade front too.

How did you set the red micro switches?

[-Elepro-]

Brad,

start to connect gnd at left one (in your photo) driver.... if you don't connect gnd to other driver (wich supply controller) the signals that it receive have not any "datum point"...... and try if it run better and cw-ccw.... (that is the main motor driver)

how did you set current dip switch in driver??

here's a trapezoidal leadscrew for you... (excuse me, i will not add any inch threaded leadscrew support in my firmware.... i love my ordered and easy metric/decimal system .... and watch world map at this link )

500mm TR10x2D Trapezoidal Leadscrew Spindle - eBay (item 220436184120 end time Oct-14-09 11:53:11 PDT)