motor driver boards

Have you codified your actual *requirements* (i.e., for the

*motor* end, not the "control" end)? You need to think about how much power you need from the drive train. This will depend on what sort of wight you are moving, how quickly you want to accelerate, friction losses (throughout the drivetrain as well as "tire to road"), top speed, etc.

This will determine the coltage and current capabilities that you need from the motor system. Then, you can look for a controller that will handle those.

Well, based on the examples that I posted I would have guessed I was looking for something in the 300 - 500 watt range (20 volts, 20 amps continuous).

That's in the ballpark of a heavy-duty electric wheelchair (assuming your motor is 80% efficient). Is that roughly the performance you are expeecting (assuming your goal is to move a person)?

If so, why not just cannabilize an electric wheelchair for motor(s) *and* controller?

This group is called sci.electronics.design. If you wanted sci.electronics.guessing, start your own damn group.

Poor communications is a terrible thing in any field. Moreso in electronics where you can't assume much commonality in terms. Motor? Cell phone vibrator? Aircraft carrier motor? What?

Next time, try a complete paragraph with detailed information, not a few links and then assume we're gonna do all the guesswork for you and then design the damn thing too.

Geez.

(Scolding humbly accepted) I won't here any more. Sorry for the trouble.

Wow, after reading a few other absolutely vicious threads, I realize I got off with a light scolding. It's apparent people obviously take advantage of the indirect communication allowed by these discussion groups to behave like absolute jerks (me not being an exception for which I am completely ashamed). So, in the hope of spreading civility to these discussion groups, I apologize to D Yuniskis for my sarcastic post and gratefully thank him for taking the time to post a response to my original query.

In the words of the immortal Bill (or was it Ted?), "Be awesome to each other".

- J

We tend to get annoyed, at times, re: the lack of information that people present in their questions. Though, for the most part, i think you will find that people will *try* to answer you -- to the best of their abilities.

But, you have a responsibility to provide people with enough information so that they *can* provide you with a meaningful answer. It is annoying/frustrating when we have to ask a bunch of questions just to figure out what *type* of answer best fits your question.

For example: "Is a Ford better than a Chevrolet?"

Here are some EQUALLY VALID ANSWERS based *solely* on that bare question:

"Yes" "No" "Sometimes" "If built before 1920" "Only blue ones" "Only the three-wheeled models" "West of the Mississippi"

etc. Do you see the point? You force *all* of us (or at least those folks who are inclined to answer) to waste time trying to figure out what you really meant to ask. We can then either:

- Spend time asking you questions to draw out this extra info

- Reply flippantly (e.g., my reply to your voltage divider query)

- Refuse to answer (e.g., all of the answers you DON'T see here!)

- Get pissed and wail at you

In all but the first case, you won't get the answer you are looking for (and, you might not in that first case, either!).

Imagine if you wanted to know:

"Is the multiport fuel injection system on a Ford better than the throttle body injection system on a Chevvy?"

How would we know that from the original (Ford v Chevy) question?

My reply to your motor question was to try to get you to think about the things that go through *our* minds when we have to answer a question re: motor controllers/drivers, for example.

You mention an electric vehicle. Do you want to move a person? An animal? Your child's "dolls"? I.e., what sort of *mass* is involved.

Are you looking for something that will be a "work horse" (e.g., a motorized cart to move yard waste around so you don't have to carry it)? Are you looking to make a little "go kart" (i.e., speed would probably be a driving force in your design)? Are you looking to make a "motorized chair" to get around the house (speed is not important -- torque and battery life are!).

Each of these goals imposes different criteria on the motor drive system. E.g., if you want to go fast, you need to be able to operate from a higher voltage because the motor generates a back EMF that makes it harder to get current into it at higher speeds. OTOH, if you want to accelerate hard, then you need to be able to push lots of *current* into the motor (torque = current).

Rather than skulk away licking your "wounds", rethink the questions you want to ask. There are lots of resources here to draw on. But, you have to draw on them *wisely* and not "willy-nilly".

HTH,

--don

was

amps

and

I suspect you should be posting to the nearby sci.electronics.basics. Note, that the advice to define the problem you want to solve is very=20 much to the point. Also include what you have considered already.

See

Pro-150 (Programmable 150)

In theory, if anyone's that much into C programming, they could adapt the existing softweare to give such control.

The software has internal current limit based on a motor current measirement.

Unfortunately the programmer who did the software for us is no longer available but the basic software contro is excellrent and well proven.

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