Choosing stepper motor...

>>1135759
If you don't want to give a specific reason for wanting the stepper fine but I'm going to need a generic reason. Is it for precision, indexing, exact speed control, braking, something else?

>>1135759
Is the weight balanced or unbalanced?

this thread is now about guessing the application

i'll start
-1200rpm ass reamer

>>1135784
>3lb wheel spinning at 1200rpm mounted horizontal that doesn't interact with other parts and is stepper driven?

Naw, an ass reamer would be vertically ordinates and interact with other parts (the ass).

My first thought was some kind of targeting mirror assembly.

>>1135759

buy a decent sized motor and fine tune your software to ramp the step rate at the optimum rate.

stepper motors can be amazingly robust when tuned properly, and can fail miserably when not.

try to have a rigid coupling between the motor shaft and the load. this helps you fine tune your ramp.

ramp means you start at the lowest step rate needed to not miss any steps, and smoothly accelerate up to 1200 rpm

I used to design stepper motors from scratch for the aerospace industry, and they always specified that we test them by starting at a fixed rate, no ramping. fucking morons. when ramped properly, a stepper is way more powerful, reliable, and predictable than when slamming it with a fixed pulse rate.

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>>1135759

They're only $16. Just go buy it.

>>1135814

Perhaps they just wanted to have you stress test the motor since the already knew you can ramp for robustness?

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>>1135835

>right in the nostalgia

>>1135759
>I'd prefer to use a stepper for (undisclosed) control reasons.

First off, fuck you for not giving details.

Second, if all you need is to spin the thing at 1200RPM and acceleration is not critical, I can only assume you mean to hold it at that speed as long as the device is operating.

If that is the case, why not just use a regular motor with a basic encoder? Control would be much simpler, and you could likely get away with a cheaper motor.

>>1135841
>Perhaps they just wanted to have you stress test the motor since the already knew you can ramp for robustness?

Your comment shows that you do not understand stepper motor dynamics any better than they did.

One thing that is hard to convey without a simulation is the fact that a stepper motor that has little inherent damping can almost never drive a purely inertial load. If you add some friction of any sort it greatly increases the motor's apparent "power".

Steppers are thought of as being simple devices, because you can easily make them go to any position without feedback. But the reality is that they are complex in their own ways, and are not anything like conventional motors, AC, DC, brushless DC, whatever.

>>1135759
I sell industrial variable frequency drives, servo drives and motors and stepper drives and motors for a living.

If a client looking for advice came and told me he won't tell me features of his application, I will gladly send him elsewhere.

Otherwise 3ph asynchronous motor and vector driven variable frequency drive would be my initial suggestion.

Vector driven means it measures output current variations (usually resulting from changes in load) and adjusts accordingly trying to keep a constant speed.

>>1136105
>If a client looking for advice came and told me he won't tell me features of his application, I will gladly send him elsewhere.

OP was not very diplomatic, but he tried to provide the information you would expect, he just made too much of a big deal about the actual application being secret.

If a customer specifies voltage, current, load inertia (not the weight as OP did), time required to reach 1200 rpm, desired precision of speed at 1200 rpm, you would not have a problem with that, would you?

If you deal with the military or aerospace typically the application is none of your business, just the specifications.

OP need to nail down the actual specs and then someone can help. If I were him I'd find a surplus parts outlet and just buy one or more to experiment with.

>>1136117
I don't expect the client to give me the entire project documentation ffs.
Just what's the drive supposed to do and how.

You must understand I cannot give advice based on "undisclosed control reasons".
That leads me to assume the machine will not just get up to speed and stay there with a constant load.
If I tell a client to take drive and motor combination X and Y and then the machine does "undisclosed stuff" that isn't within spec,
something breaks, warranty disputes, and most importantly the client instead of getting the machine to work wasted its time and resources.

This sums up to basically, op stop being the proverbial faggot because if you look for advice on 4chen its fucking nothing top secret, unless you have some ignorant reasons for a stepper and are ashamed to admit it.