Iain, more volts helps when making the motor run faster and smoother but the current is set by the driver.  From limited data on Amazon the coil resistance is 0.9 ohms so would take nearly 30A from a 24V supply if the driver let it!  The same data says that the holding torque is 2.8Nm?  If you have access to a power supply then trying more volts might help.

Have you tried increasing the microstep ratio.

I use a somewhat smaller motor on my VMB mill power feed driven from a DRV8825 driver on 24V.  It also complains at one end of table travel because the table friction increases, but the coil current is something like 1A or less.  Some adjustment of the gibs might help?

Do you have any mechanical reduction to the feed screw?  I have a 2:1 timing belt drive.

The TB6600 drivers don’t have a great reputation and apparently there are ones around that look the same but have different less capable driver chips inside.

As above, more volts helps maintain torque at speed (to maintain current against the back EMF generated by the running motor). I don’t believe it will do much for starting torque.

That’s already quite a powerful motor for the NEMA23 form factor, so it may be that the torque required is too great, and you will need to add reduction gearing (2 or 3:1 timing belt).

However…

You say you’re using a ‘TBA6600’ driver – is it one of the generic ones that are all over Amazon, Ebay & Aliexpress?

If it offers 32:1 microstepping, it hasn’t got a TBA6600 chip inside – likely a TB67S109AFTG instead which, despite what the printing on the case says, is limited to 3 amps output.

If so, you could get a 40% increase in torque by running a drive that allowed you to run the motor at its rated 4.2 amps.

A fairly cheap drive (that uses the TBA6600 chip) is sold as the ‘DIV268N’ – billed as a 5A drive.

I bought a couple from ‘Maker’s Hut‘ and they seem OK, but they’re old fashioned and crude compared to more expensive drives.

You could:

• Set the microstepping to 2 or 4 for more torque.
• replace the driver by a digital driver like the DM556. These drivers change to full step when the motor is running at a reasonable speed. This results in more torque.
• replace the driver by a TMC2209 stepstick driver. I use these on my mill and I am going to use them on my 2 CNC lathes. In my experience, the TMC2209 driver delivers 4 times more torque than a TB6600 driver and they run very quit.

Some confusion here, this is a stepper motor with an electronic drive,

• Only the absolute maximum speed of the motor is determined by the supply voltage.  Applying more volts allows the motor to accelerate faster without losing steps, but motor speed isn’t proportional to voltage.
• The working maximum speed of an adequately powered motor is determined by the input pulse rate and the mechanical limits of the motor.    This type of motor is designed to step moderately accurately at lowish RPM and to hold position when stopped.  They aren’t boy racers!
• Power (rate of work) and Torque (turning power) of steppers depend on Amps.  Always look at the amps, because volts are less important.
• The motor is pulsed with an electronic driver that can be set to step the motor at 200 steps per rotation, giving the fastest coarsest RPM, or micro-stepped at up to about 60,000 steps per rotation (much smoother and far slower).  When the motor is stopped, the driver provides enough power to hold the rotor in position.   The driver is fitted with a limiter than prevents too many amps being pumped into a held motor  – 4.2A is a reasonable limit for this motor, more would overheat it.

What power supply do you have Ian, Volts, Amps and Type?

The PSU has to provide enough amps to drive the motor.  24V at 6A should do, but the type matters too.   I always use regulated LED power supplies for this, because they’re common as muck and cheap, not because they’re best practise, and one day I shall come unstuck.  Regulated supplies aren’t ideal for driving stepper motors because a regulator designed for a steady load may not cope with a stream of nasty short sharp on/off pulses.  If the regulator is discombobulated by a pulsed load, the power output available at the motor will be throttled.  The ideal power supply for this stepper would be 40Vdc at 6A unregulated, not easy to find.

For winding a milling table, where accuracy and repeatability don’t matter much, I’d go for speed, setting the driver to 200 steps per revolution.  Above all the power supply has to get at least 4A into the motor.   Arguably for this application something like a dimwitted windscreen wiper motor with a PWM controller and a reduction belt drive is a better bet.  Smart steppers are good for rotary tables, where the ability to turn and set an accurate angle is essential.  Wiper motors are hopeless for spinning rotary tables, but good at fast crude movements. Unlike steppers, more volts causes more amps to flow in a wiper motor, and their speed and power increases as expected.   Steppers don’t behave the same way.

Dave

Especially with a higher supply voltage, the current consumed from the supply  is significantly less than the coil current you set since the driver operates as a switched mode power supply. The input power equals the output power plus a bit for efficiency.   Easy to over spec the supply!  John your transformer rectifier proposal would be just fine, I used exactly that in my lathe conversion. I would avoid any drive with a  tba6600 chip, they are out of the ark. I’m not sure what arduino code you use but GRBL is free and handles all the acceleration stuff.

On 11 November 2023 at 06:24 Iain Downs Said:

Hi, John

…

Also, John, with an unregulated supply is there not a risk of the voltage rising somewhat above nominal if there is no load?  So if the transformer is specced as 24V, which is what it would deliver under load, under no load it could rise to quite a bit more (off hand about 1.4 times as much (inverse of root mean square)?  That could be over the driver’s allowed voltage…

 

 

Oaom

In your example the transformer gives 24v rms, which is 1.414×24 = 34v peak which is what the smoothing cap will charge to off load.  The cap needs to be sized so the load current will not cause an unacceptable ripple between charge pulses from the rectifier.   But that off load calc gives the max voltage which you need to be less than the max driver supply.