Motor Info

[elogicca]

I have 3 23lm-c004-38

Anyone have any info on these?

can these be driven unipolar at 24v 2.5 amp?

they are 6 wire motors, wires are sealed into the casing pretty small gauge

[jeffs555]

http://www.nmbtech.com/pdf/motors/Hy...StepMotors.pdf

This sheet says they are 1 amp motors, so 2.5amps would be way too high. Also, they have 7ohm coils(ie 7volts at 1 amp), so 24v might work, but would be a little low for a supply voltage. For best speed, you generally want the supply voltage to be 8 times or more the rated voltage of the motor.

[elogicca]

Wow 8 times the voltage, didn't know that .... ok so amperage you stay at the rated amperage and you bring up voltage for speed, torque is allways a constant?

[NC Cams]

Generally speaking, current flow provides torque and voltage generates RPM.

However, using Ohm's law, a higher voltage applied across the same resistance results in higher current. Thus, at 7 times the rated voltage, you'll have high speed plus high torque provided you can ultimately limit current so that it does not rise excessively and cause stuff to fry.

Recall that you can't "shove" current thru a device - you draw it as a function of Ohm's law. Thus, just because a power supply CAN supply say 10 amps, that doesn't mean it will - current flow is a funtion of the voltage it puts across the load resistance, again pursuant to Ohm's law.

Thus, any current limiting is done by either folding back voltage via the control strategy after the initial "hit" or putting resistors in series with the coils to resistively limit current, again using Ohm's law.

BTW,

E= I x R.

One MANDATORY to learn equation for the budding DIY CNC'er. Other helpful ones to learn are those that involve series and parallel resistance.

[elogicca]

Ok, now i'm confused ......

I have a unipolar motor whats the best way to run it for torque, speed is a side issue

Half winding
Full Winding

Series
Parallel

Also what rated currents can be run at each of these settings???

Thsnks

[H500]

What drive are you using? That will determine what you can do.

[elogicca]

PMinMo's 72805a's

Thanks

[H500]

Do you have a link to it?

[jeffs555]

Thats an A3977SED based bipolar board, so 24 volts is nearly the max voltage for your drives. Full winding would be painfully slow at only 24 volts, so run it at half winding. Half winding current would be the same as unipolar current. You can't run a 6 wire motor parallel. However, on many 6 wire motors, you can carefully remove the end cover, find where the coils are joined at the center tap, split them and bring out two more wires. This would let you run parallel. For parallel connection you can normally use 1.414 times the unipolar current.

PS Series and full winding are the same thing. If you wanted to try it, you would use .707 times the unipolar current, but like I said it would be very slow.

[elogicca]

Ok so i opened up one motor, and did the following, removed black / white wires, splut the center tap of each coil and added jumpers

Originally it was

green ---- white ----- green/white
red ---- black ----- red/white

now

green --- green/white --- green ---- green/white
red --- red/white --- red ---- red/white

when i hook up the motor i get no action at all

[elogicca]

On another note, if i take out all my jumpers and reconnect the center tap it works half winding, same config with center tap split = nothing

[H500]

The coils must be parallelled in the proper polarity and proper coil pairs. If you do it wrong, you could fry both the motor and controller.