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My purpose is not to have several discrete voltages, but a continuously variable voltage output between 0 and 90V. Sorry if I didn't make that clear. Many times one (particularly those not...

I was actually thinking of using it to feed the motors, but maybe that isn't necessary.



I don't see how the isolated variac will save any of your electronics. I see it as a safety net between...

Everyone needs a variable power supply for bench testing of your motors right? Well, a lot of the motors out there seem to run on 12 & 24V, which is no problem, but what about the ones that take...

Al,

Thanks for the file. That clarifies a few things. I never realized how significantly different brushed and brushless DC motors really are.

Chad

Thanks for all the great info on these motors.



So is a sinusoidal PWM signal used to drive DC brush-less motors or does it use constant-amplitude PWM?

Chad

I find the idea of a 3-phase (brushless) DC motor almost confusing -- but I get the impression that each "phase" is used to drive a coil that is responsible only for 360/3 = 120 degrees of mechanical...

eat,

got your PM and saw the pictures. Looks good, but I'm still confused as I didn't see a description of what this thing will do. What is the contraption that you're building, or what is it...

Al,

I just saw a brushless dc motor for the first time today -- my brother's one came in the mail. The way he was explaining it to me was that it had 3 separate coils that had to be driven...

RotorRouter,

I may be mistaken, but I think the concern centers more around any level of slop between the wheel and the worm gear, as any level of slop will allow the table to oscillate back and...

I've never put together a CNC system, but I do know that not only the drive, but also the control scheme is very different for AC and DC servo systems, with AC being the more "complicated".

The...

eat,

Not expecting pictures or anything, just curious what you're building.

I'm just getting started helping my brother build a CNC router. He's an electrical engineer and I'm a little more...

Al, so the mechanical design of a 4-th axis rotary table is different than a manual rotary table? (i.e. do they use a some kind of ballscrew-type drive?)

The reason I ask is that I thought a 4-th...

You almost got it...

40 in-lb * (16 oz/lb) = 640 in-oz

not sure about the "tc", but would presume it refers to continuous torque rating.

Whatcha building? I'm new here, so I may not have...

Just joined the board here...

I live in Tucson, AZ. My brother and I (He's an electrical engineer, I'm a little more mechanical) are in the beginning stages of building a CNC router. We've...

You were. I went to bed around 12:30-1:00, what's the matter with you? :D



....And it is in response to my very first post :D What a ka-winky-dink!



Thanks for the tip. Sounds like you...

I'm a little uncertain about servo tuning as well. I envision tuning the PID parameters, most likely while the system is unloaded and not cutting a part. However, I would think those parameters...