native34
11-05-2009, 12:10 PM
Could someone please explain the paragraph below in a for dummies explanation for me please as i have no understanding of this please see below?
The place to start is to determine the load torque in oz/in. Be sure to include the torque necessary
to accelerate the load. Next come up with the maximum speed the application has to operate at in
full steps per second. Multiply the two together and then divide the result by 4506 to calculate the
power in watts necessary to meet the application requirements. Pick a motor at a power supply
voltage that provides a 40 percent reserve power margin above your requirements
Al_The_Man
11-05-2009, 12:44 PM
See a couple of references in Post #5 to get a gist of what is involved.
http://www.cnczone.com/forums/showthread.php?t=86975&highlight=inertia+ratio
Al.
tooManyHobbies
11-12-2009, 08:30 AM
The place to start is to determine the load torque in oz/in.
Torque is in units of oz-in, not oz/in.
tom
KIMFAB
11-12-2009, 11:24 AM
Torque is the amount of force required to turn a shaft. It is expressed in oz-in or ft-lbs or fig-newtons or some other measurement that involves a weight and a distance.
Turn your crank handle so it is parallel to the floor and start putting one ounce weights on the end of the handle. When the handle turns, multiply the number of ounces used by the distance from the center of the shaft to the place you attached the weight.
Your result is oz-in of torque required.
Now to figure power. Count the number of turns it takes in one second to move the table at the desired speed. Multiply this by the number of steps per turn from the stepper spec.
Now take this figure, multiply it by the torque found above and you should be on your way. Not sure where the 4506 comes from but is probably calculated using some formula involving the power you just found.
Hope this is not too basic for you but nowadays the schools don't bother to teach basic physics and instead are concentrating on putting condoms on cucumbers.
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wildwestpat
11-12-2009, 04:30 PM
See a couple of references in Post #5 to get a gist of what is involved.
http://www.cnczone.com/forums/showthread.php?t=86975&highlight=inertia+ratio
Al.
Al do you have any pointers to similar information on load matching for steppers please?
Many thanks
Pat
Al_The_Man
11-12-2009, 05:34 PM
I have never used steppers so far in any application, but I know the Kollmorgen sizing software referenced to in the link includes steppers in the selection process, I know that both servo's and steppers in the software is geared to the Kollmorgen line, I usually just use it as a guide line when selecting a motor for a particular application to get a rough motor load inertia match.
Over time I have come across alot of info off the manufacturers sites, and downloaded considerable information, which I found was a fortunate habit as many sites have changed and no longer appear to offer the same info anymore.
e.g. Sanyo Denki had an excellent Handbook of Servo Systems on their site which no longer exists.
The moral is, if you see it, save it.
Al.
heba66
11-13-2009, 05:43 AM
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bye
wildwestpat
11-13-2009, 08:57 AM
Thanks Al
Yes steppers are given treatment and included in the site you gave the link for along with a lot of data on encoders and servos - a first class refference and I have now saved as much as I think is relevant.
Thanks again
Pat