easydriver + stepper motor stalls

[scalance]

Hi guys,
I'm new in this forum and I need some help please.
I built a small 3 axis cnc machine at home using easydriver and 3 of SY28STH45-0674A stepper motors (Changzhou Songyang Machinery & Electronics New Technic Institute ) , the motor turn well with no load but stalls even if I touch it with my finguer, the power supply I use is 24V at 2 Amps.
I've wired up one phase to see if the motor will hold hard and will not turn if I make it turn with my hand but it turns.
I don't know if the problem is that amps are not enough or if the motors are not so strong.
Thx verry much and have a good day all.

[doorknob]

Do you have the potentiometer set close to the "max" current setting?

Your motor is rated for 670 mA per phase, and the driver is rated for max current of 750 mA.

Depending on which version of the circuit board you have, the min/max legend on the board may be incorrect (reversed). According to Easy Driver stepper motor driver, the silk screen min/max legend is reversed on the version 4.3 board.

The motor is not a very powerful one - the holding torque is rated at 950 g-cm (which, if I have calculated correctly, is equivalent to about 13 oz-in).

I've wired up one phase to see if the motor will hold hard and will not turn

The easy driver is designed to operate in 1/8 microstepping mode. In that mode, the current through the two phases will likely be different. If you have only wired up one phase, it is possible that the current going through that phase is very small, rather than being close to the maximum available current.

[scalance]

thx doorknob's for answering.
I'm using the version 4.4 and the pot is set to max but the motor still stalling,
I didn't wire the phase using the driver but power supply directly to it and it stalls.
thx verry much

[doorknob]

If you wired one phase directly to the power supply, did you use a 4.5-volt (or 5-volt) supply or the 24-volt supply? (applying 24 volts directly to the winding would not be recommended)

I would expect that if you used a 4.5-volt supply, the current drawn by the winding should be close to the rated current (you should be able to measure that current with an inline multimeter, because the current is not being chopped by the driver, but beware of inductive spikes if connecting or disconnecting the coil while current is flowing), and the holding torque should be close to the rated torque.

[scalance]

I tried with 5v and 12 v it's the same, I can stop it with my finger ^^.

[scalance]

Please heeeeeelp , I bought those motors from spain, I can't have other ones and they are expensive.
If they will not work, can anyone please tell me how to use a wahsing machine or a dc motor instead of steppers.
Thx so much guys.

[photomankc]

I don't know what you are expecting from a motor and driver that are as weak as a kitten? The motor specs that I see equate to 11 or less oz-in's. People building even small CNC machines are generally using stuff with hundreds of oz-ins of torque. The motors you have are simply weak and the driver is not suited to anything but a small, weak motor.

I know of no way that you can adapt a washing machine to such a use nor simple DC motors. You have to spec out what the machine needs and buy drivers and stepper motors that can meet that. The BigEasyDriver is a similar driver to what you have that can deliver close to 1.25A without cooling and better than 2.0A with cooling. That's going to get you much further along in being able to select a reasonable motor than the 0.75A is for the EasyDriver.

[scalance]

Thx verry much photomankc.
It's a pitty to not be able to use this kind of motors in an application :'( and it's a pitty having spent money in nothing but it's good that I learned something .
Thx guys