Motor

Hi,

I am controlling a DC motor via micro. DC motor draws 2A at full load and requires 12V. Motor needs to move 30 degrees after every hour. Total required rotation is 180 degrees. Motor starts from zero degree, moves 30 degrees every hour reaches 180 degree and then travels back to 180 degree without stopping and then repeats, 30 degree every hour. I am using 12 V 4AH Lead acid battery,


Motor moves six times in 6 hours . Each time motor moves 30 degrees, it draws 2A. But it moves for a very little time. How can I calculate that time?
Plus what would be current draw for the entire cycle?
How long the batteries will last without charging?

jess

 

On Thursday, December 17, 2015 at 11:23:48 PM UTC-5, jsscs...@gmail.com wrote:

Hi,

I am controlling a DC motor via micro. DC motor draws 2A at full load and requires 12V. Motor needs to move 30 degrees after every hour. Total required rotation is 180 degrees. Motor starts from zero degree, moves 30 degrees every hour reaches 180 degree and then travels back to 180 degree without stopping and then repeats, 30 degree every hour. I am using 12 V 4AH Lead acid battery,


Motor moves six times in 6 hours . Each time motor moves 30 degrees, it draws 2A. But it moves for a very little time. How can I calculate that time?
Plus what would be current draw for the entire cycle?
How long the batteries will last without charging?

jess

Use a stepper motor, not a DC motor

 

I am stuck with DC motor, can not change to stepper now. I am stuck with this problem for couple of days. I will appreciate any feed back.

 

[amdx]

On 12/17/2015 10:23 PM, jsscshaw88@gmail.com wrote:

Hi,

I am controlling a DC motor via micro. DC motor draws 2A at full load and requires 12V. Motor needs to move 30 degrees after every hour.

Total required rotation is 180 degrees. Motor starts from zero degree,
moves 30 degrees every hour reaches 180 degree and

then travels back to 180 degree without stopping and then repeats, 30
degree every hour. I am using 12 V 4AH Lead acid battery,

Motor moves six times in 6 hours . Each time motor moves 30 degrees, it draws 2A. But it moves for a very little time. How can I calculate that time?
Plus what would be current draw for the entire cycle?
How long the batteries will last without charging?

jess

Is this a geared motor?
How do you move it only 30 degrees?
How many clock pulse of the micro is the motor on.
You can't stick a scope on it and see the motor is on for 750ms,
6 times a day and 3.8 seconds 1 time a day. Then calculate from there?m
What is the wave form of the current, for a few us the current my be
10 amps, if you pulse it full on.

Mikek

 

On Fri, 18 Dec 2015 09:40:33 -0800 (PST), jsscshaw88@gmail.com wrote:

>I am stuck with DC motor, can not change to stepper now. I am stuck with this problem for couple of days. I will appreciate any feed back.
Measure the RPM of the motor while it has enough load to draw 2 amps.
Divide 1 by the RPM and you will know how long 1 revolution takes.
Divide that by 12 and you will know how long it takes to move 30
degrees. Multiply that by 6 to get total run time per hour. Oh wait,
the motor needs some time to accelerate and decelerate. Are you
wanting to know how long to keep the motor on in order for it to turn
30 degrees? If so you will need to provide more information. Like the
accel. and decel. times. Since you are using a microcontroller you
could use it with a couple sensors to measure motor on time. Your
question really can't be answered accurately unless you provide more
information. If you really can't change to a stepper and want to know
how long to run your motor then probably the easiest thing now for you
to now is to run the motor for a certain length of time and measure
how many degrees the shaft turns. Do this several times to make sure
the motor shaft always turns the same amount. Then try a different on
time and measure that. Use those times to figure out how long the
motor needs to be energized in order for it to turn 30 degrees.
Eric

 

[Jasen Betts]

On 2015-12-18, jsscshaw88@gmail.com <jsscshaw88@gmail.com> wrote:

Hi,

I am controlling a DC motor via micro. DC motor draws 2A at full load and requires 12V. Motor needs to move 30 degrees after every hour. Total required rotation is 180 degrees. Motor starts from zero degree, moves 30 degrees every hour reaches 180 degree and then travels back to 180 degree without stopping and then repeats, 30 degree every hour. I am using 12 V 4AH Lead acid battery,


Motor moves six times in 6 hours . Each time motor moves 30 degrees,
it draws 2A. But it moves for a very little time. How can I calculate
that time?

you can calculate it from the speed of the motor.

> Plus what would be current draw for the entire cycle?

you said 2A while running.

> How long the batteries will last without charging?

about 8 hours run time if they only power the motor.

jess

--
\_(ツ)_

 

[Tim Wescott]

On Thu, 17 Dec 2015 20:23:43 -0800, jsscshaw88 wrote:

Hi,

I am controlling a DC motor via micro. DC motor draws 2A at full load
and requires 12V. Motor needs to move 30 degrees after every hour. Total
required rotation is 180 degrees. Motor starts from zero degree, moves
30 degrees every hour reaches 180 degree and then travels back to 180
degree without stopping and then repeats, 30 degree every hour. I am
using 12 V 4AH Lead acid battery,


Motor moves six times in 6 hours . Each time motor moves 30 degrees, it
draws 2A. But it moves for a very little time. How can I calculate that
time?
Plus what would be current draw for the entire cycle?
How long the batteries will last without charging?

I thought I answered this already today. Oh well -- once more into the
breach.

First, speaking about answering this already, you've asked similar
questions before. The answers aren't going to change much.

You have not given enough information. The two missing critical bits
are, one, how the mechanical load you're putting on the motor compares to
it's rated "full load", and, two, how long it needs to turn to travel 30
degrees.

Don't answer these questions and no one can help you. Do answer these
questions and a moderately good student in high school physics should be
able to answer your questions.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

 

[Tim Wescott]

On Fri, 18 Dec 2015 17:29:44 -0600, Tim Wescott wrote:

On Thu, 17 Dec 2015 20:23:43 -0800, jsscshaw88 wrote:

Hi,

I am controlling a DC motor via micro. DC motor draws 2A at full load
and requires 12V. Motor needs to move 30 degrees after every hour.
Total required rotation is 180 degrees. Motor starts from zero degree,
moves 30 degrees every hour reaches 180 degree and then travels back to
180 degree without stopping and then repeats, 30 degree every hour. I
am using 12 V 4AH Lead acid battery,


Motor moves six times in 6 hours . Each time motor moves 30 degrees, it
draws 2A. But it moves for a very little time. How can I calculate that
time?
Plus what would be current draw for the entire cycle?
How long the batteries will last without charging?

I thought I answered this already today. Oh well -- once more into the
breach.

First, speaking about answering this already, you've asked similar
questions before. The answers aren't going to change much.

You have not given enough information. The two missing critical bits
are, one, how the mechanical load you're putting on the motor compares
to it's rated "full load", and, two, how long it needs to turn to travel
30 degrees.

Don't answer these questions and no one can help you. Do answer these
questions and a moderately good student in high school physics should be
able to answer your questions.

Oh, I DID answer the question, in comp.arch.embedded.

Please don't multi-post!

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

 

[John Larkin]

On Thu, 17 Dec 2015 20:23:43 -0800 (PST), jsscshaw88@gmail.com wrote:

Hi,

I am controlling a DC motor via micro. DC motor draws 2A at full load and requires 12V. Motor needs to move 30 degrees after every hour. Total required rotation is 180 degrees. Motor starts from zero degree, moves 30 degrees every hour reaches 180 degree and then travels back to 180 degree without stopping and then repeats, 30 degree every hour. I am using 12 V 4AH Lead acid battery,


Motor moves six times in 6 hours . Each time motor moves 30 degrees, it draws 2A. But it moves for a very little time. How can I calculate that time?

Don't. Measure it.

 

[default]

On Thu, 17 Dec 2015 20:23:43 -0800 (PST), jsscshaw88@gmail.com wrote:

Hi,

I am controlling a DC motor via micro. DC motor draws 2A at full load and requires 12V. Motor needs to move 30 degrees after every hour. Total required rotation is 180 degrees. Motor starts from zero degree, moves 30 degrees every hour reaches 180 degree and then travels back to 180 degree without stopping and then repeats, 30 degree every hour. I am using 12 V 4AH Lead acid battery,


Motor moves six times in 6 hours . Each time motor moves 30 degrees, it draws 2A. But it moves for a very little time. How can I calculate that time?
Plus what would be current draw for the entire cycle?
How long the batteries will last without charging?

jess

Why do you want to "calculate" the time? To achieve position
accuracy? If that's the case, what accuracy do you require and how
repeatable does it need to be?

Ordinarily you might do something like that with an encoder on the
motor or gearbox output.

But if you just need to stop at the same points every time, you can
use a cam and "zero seeking" limit switches. You turn on the motor,
but the motor turns itself off when the limit switch opens the power
circuit to the motor.

 

[Cydrome Leader]

John Larkin <jjlarkin@highlandtechnology.com> wrote:

On Thu, 17 Dec 2015 20:23:43 -0800 (PST), jsscshaw88@gmail.com wrote:

Hi,

I am controlling a DC motor via micro. DC motor draws 2A at full load and requires 12V. Motor needs to move 30 degrees after every hour. Total required rotation is 180 degrees. Motor starts from zero degree, moves 30 degrees every hour reaches 180 degree and then travels back to 180 degree without stopping and then repeats, 30 degree every hour. I am using 12 V 4AH Lead acid battery,


Motor moves six times in 6 hours . Each time motor moves 30 degrees, it draws 2A. But it moves for a very little time. How can I calculate that time?

Don't. Measure it.

Agreed. motors and gearboxes do weird things once you factor in backlash
and how they coast.