Steppers do run hot, this is the nature of the beast, the important thing is that the mean level of current should be exactly what the motor plate states at all times.
Never exceeded, at least for VERY brief moments only, if at all.
.
Hello good morning everyone, I would like to ask a question to the forum, it is about the operation of my nema 23... they work at a high temperature and when placing your hand you cannot stand it, I have read that it is normal according to this forum, but always I was left with the doubt, this happens obviously after a prolonged period of work.
Thanks for your comments.
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Steppers do run hot, this is the nature of the beast, the important thing is that the mean level of current should be exactly what the motor plate states at all times.
Never exceeded, at least for VERY brief moments only, if at all.
.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.
Hello AL, thanks for answering, I understand what you are saying, I am managing them with a Gecko G540, (this controller is wonderful). Additionally, the software that I am using is Mach4 hobby and here comes the second query, will I have to configure some setting in Mach4 regarding the settings and the motors tab? sorry for the basic questions.
Actually I have never really used Mach3 or Mach4 for a system, most of mine was using the PC plug in cards from Galil Motion.
I have loaded mach3 recently as i am designing a means of controlling a TM drive and DC spindle motor as Mach3 outputs a PWM signal directly which the TM requires, i.e. no analogue used.
The Mach3 seems easy to set up, one of the BOB's I am using gives some set up procedure, it is the one from ECG-SAVEBASE there is a manual out there on line.
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.
What do you do if there is nothing on the motor that says what the amperage is supposed to be? Is there an empirical way of determining it?
[FONT=Verdana]Andrew Werby[/FONT]
[URL="http://www.computersculpture.com/"]Website[/URL]
Hi,
the practical limitation on current in a stepper is heat. A stepper will still run, albeit with less torque, at a lower current.
The simple way would be just to start at 1A, and slowly work your way upwards until you have found what you determine to be the max temperature youIs there an empirical way of determining it?
want your steppers to run at.
The vast majority of the heat generated by a stepper is resistance loss, also called RI2 loss. There will be small but measurable contributions
from hysteresis loss, and eddy current loss, but the two combined are less than 10%.
High current steppers have low to very low windings resistance, for example a Leadshine 23 size 57CM26 of 386oz.in with a rated current of 5A and a winding resistance of 0.44Ohm.
The power lost in the winding:
P=R. I2
=0.44 . 52
=11W per winding, for a total of 22W for the motor.
A motor of the same size but lower current, for example a Leadshine 23 size 57CM26-4A of 369oz.in with a rated current of 4A ad a winding resistance of 0.8 Ohm.
P=0.8 x 42
=12.8W or 25.6W for the motor.
Note both these motor are the same size, including the motor length. As a consequence they can both dissipate about the same power for the same temperature rise,
which sort of makes sense. The power dissipation a stepper can handle is related closely to its size. A high current stepper will dissipate about the same as a low
current stepper of the same size.
If you have either a very good multimeter, or better still a Kelvin Bridge used to measure low resistances you could measure the winding resistance and therefore estimate
the current that would cause an 11W power dissipation in each winding. You might increase it if the stepper is longer than 3 inches like my two examples and decrease it
if your stepper is less than 3 inches long.
If your in Christchurch...call in, I'll measure it for you with my Kelvin bridge, its good to about 100uOhm.
Craig
Interestingly, my motors are NEMA23 KL23H2100-35-4A (1/4” Single shaft with a flat) 381 oz-in, the nature of the beast as AL_ says.
Greetings.