Stepper voltage

[glentner]

I just bought some powermax II steppers (214 oz/in bi-polar) and plan on "making" my own drive using a PLC and a joystick (or something similar).
I got ancy and found a wiring diagram online and connected a 24v power supply to one of the sets of wires (per the diagram). I didn't seem to get any holding torque from the motor.
My question is: Is this because the motor says its 65v and I'm only giving it 24v?

I'm pretty new at this.

Greg

[ger21]

Did you just get these from Ebay, for about $100 a pair? I've seen a bunch there lately. I don't believe you can just hook them to a power supply and get them to work. Buy a Xylotex board and they'll work just fine. http://www.xylotex.com. I've got the 253 oz-in motors with the same amp rating as yours and they work fine with the Xylotex.

Gerry

[pack rat]

I am not an electronic guy they will be here in minutes. My guess is that 65V refers to maximum voltage that you can apply but you have to have a pulse driver ( or generator) to run the motor. 24V translates into 34V DC. The motors are fine you just need the driver and the torque will show up when properly hooked up.

[abasir]

My main concern is as follows:
Most high torque stepper motor coil are less than 1 ohm. Assuming your 24V power supply have enough juice, applying 24V to a 1 ohm coil will result in in 24 amp current; which may cause the coil to burn up. Looking at PowerMax datasheet, I don't see any of the motor having current rating higher than 10A. Did you check for continuity after the 'fancy' test?

[glentner]

Yep I did get them from Ebay, I got 3 for $175.

My original idea was to use my PLC for the driver. From what I understand, the driver turns a signal into a series of pulses to the motors. I would think that the output voltage is going to be constant no matter how fast the pulses are. The spec sheet for powermax shows the sequence to step the motor forward/reverse so my idea was to program my PLC to send the correct pulse sequence to relays that would send the required voltage. I probably wouldn't be able to pulse as fast as a driver could, but at least I could use my existing hardware. The analog input connected to a joystick would change the pulse speed.

Again I'm shooting from the hip on all of this, so I may be way off base in my thinking. Thus why I'm posting this.

[glentner]

Gerry:
Is it possible that you could connect a volt-meter to the ouput of your xylotex driver to see what voltage it is actually sending?

[glentner]

Now for my 3rd reply in a row.....

I did some looking and I think I'm just going to buy a driver and the software. I thought that the board was going to be a lot more expensive then it is.

[johnbutler]

I've also got several of the Powermax II motors and have ran them at 12 volts with a 1 ohm resistor in each phase. I'm interested in what voltages and resistances others have used on these motors. Also, glentner mentions wanting to use relay outputs from the plc to control the driver. The relay outputs of most plc's can't cycle faster than 5 or 10 cycles per second at maximum. With the Powermax having 200 steps per revolution that gives between 20 and 40 seconds per revolution. You may want to consider going to a transistor output plc. The inexpensive plc's that have transistor output and have stepper signal ramping designed into them start for around $150. Using an old computer is even cheaper.
John