Stepper motor Voltage

[metron9]

My first project I used the stepper3+1 from stepper3.com and bought their motor nema 23 5.1 volt 1 amp 5 ohms

After reading many threads on how the motor should be run at at least 4x the rated voltage. I also understand three types of current control, resistors/transistors/ and chopper drives. This system I have is locked in to full steps and thus I have some resonance problems at higher speeds and I am thinking maby because I am running it at 5volts that is a major problem.

I would like to try the 12 volt supply I have but I have a question or two.

The information stepper3 gives on using a resistor says the resistor should be connected to the center tap of the coil. However there are 2 coils and 2 center tap connections. It seems I need 2 resistors but I can see a problem that if two seperate resistors are used that are not exactly the same ohms, I would have a problem as this is how microstepping is done.

So the question, can I use a power resistor in series with the power supply terminals on the board. (each motor connsction has its own set of terminals for motor power on this board)

Question 2. If that is ok, would I use the resistor on the + side or the - side.

My next Motor/driver will be from Salem controls as they have microstepping and sell all the components motors/breakoutboards/drivers/power supplys and wiring and a very easy to understand web site that makes it easy to select what you need. As I am new to CNC buying everything from one source that works together is a nice way to do it.

I have looked at the Gecko G901 Step Pulse Multiplier at $39.00 as perhaps an add on board that would give the system I have microstepping but I am not sure if it will work with the driver board I have or if it is just for other Gecko drives. I dont really need any more speed on the system I have built now but the resonance and loudness of the full steps just dosen't sit right with me.

I am almost done with the X table and I will post some pictures when I am finished.

I have a project I would like to do that I need to lift about 200 lbs vertical in increments of about 1/4 inch. Its a sheet stacker I want to be able to index it down while filling it and then index it up while unloading it. I am thinking a cheap way would be to use an air cylinder and a ratchet and prawl setup instead of motor and reducer that runs almost a grand. Any suggestions on how to do this project on the cheap would be appreciated.

[lurch]

Is the 200lbs. from the sheet stock or the table/rack that holds them? I'm a packaging engineer, so problems like this fascinate me....

[metron9]

Originally Posted by lurch Is the 200lbs. from the sheet stock or the table/rack that holds them? I'm a packaging engineer, so problems like this fascinate me....

The sheet stock. I have been looking at scissor jacks that have a hydraulic jack handle. Found one for $495.00 Firestone makes pneumatic actuators that could be used to move the handle under program control. Then using another very small actuator to turn the release knob to lower the table would do the trick.

The battery operated lift jacks I have looked at all run over 2 grand. I need to make about 8 of these so that's why I am trying to figure out a cheap way of making them.

If I had a better math background/Physics I would be able to calculate the pullys needed to do the job with a stepper motor using a basic stamp PLC to monitor the height of the sheets stacking on the table to lower it using the release valve. When the operator rolls that table full of sheets back to the perss he would flip a switch and the table would maintain the height of the stack at the same level. Using air the table would have to be "plugged in" each time it was moved. I was thinking if I could do it with a stepper or servo system I could have onboard batteries but they would have to get plugged in overnight. Cords and electric are more dangerious than pluggiing in air so that's why i am thinking the air route for this project.

Ref:http://www.firestoneindustrial.com/Industrial/index.htm

[lurch]

Sheet dimensions? Sheet material? Working environment? Standalone dispenser? I need details in order to properly ruminate on your problem set. This could be done with a pulley counterweight system and a lifting screw, maybe.
What overall size are you shooting for on this dispenser? Pwer and or air hookups available. Is usability by operator a consideration. Will training be necessary? I like KISS as a rule, Keep It Simple Stupid. A Dumb machine is easier to maintain and operate, the simpler the better. Pm me with answers and questions, no idea is too far affield. But, you don't want to reinvent the wheel either....