pwm frequency
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Posts: 46,084
Hello all,
I want to run a motor with pwm,so i can alter the speed. how can i determine
a good frequency and the good pulse/pause or is the up time equal to the
downtime?
I thought that i read somewhere that if the frequency to low
(or to high???) the motor becomes hot (if it isn't turning)
greetings pieter-jan
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I want to run a motor with pwm,so i can alter the speed. how can i determine
a good frequency and the good pulse/pause or is the up time equal to the
downtime?
I thought that i read somewhere that if the frequency to low
(or to high???) the motor becomes hot (if it isn't turning)
greetings pieter-jan
_________________________________________________________________
Add photos to your messages with MSN 8. Get 2 months FREE*.
http://join.msn.com/?page=features/featuredemail
Comments
narrower the pulses you give the motor the slower it turns. Since maximum
voltage is applied to the motor, the inherent power (torque) of the motor is
realized as oposed to applying a lower voltage to turn the motor slowly.
The actual pulse width necessary for your application must be determined
based on power required, power available at what speed and load. Individual
motors operate differently so, often, it is best to just try something as a
starting point (50%) and adjust as necessary.
Jim
Original Message
From: Pieter-Jan van Diepen [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=x95EO-kfnQbwM0voMcVUA1GNtFlLPYIPJPK2vqWqfsgLSj3jrBACXEE7YhszDV5M0ZHJ5N8GSqCvP3E]diepenpj@h...[/url
Sent: Monday, March 10, 2003 4:49 AM
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] pwm frequency
Hello all,
I want to run a motor with pwm,so i can alter the speed. how can i determine
a good frequency and the good pulse/pause or is the up time equal to the
downtime?
I thought that i read somewhere that if the frequency to low
(or to high???) the motor becomes hot (if it isn't turning)
greetings pieter-jan
_________________________________________________________________
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inputs of an hbridge driving the motors. It works
well. ANd if u do this u neednt worry abt the pulse
widths
--- Jim Forkin <jjf@p...> wrote:
> The closer you get to 100% (full on) the faster the
> motor turns, the
> narrower the pulses you give the motor the slower it
> turns. Since maximum
> voltage is applied to the motor, the inherent power
> (torque) of the motor is
> realized as oposed to applying a lower voltage to
> turn the motor slowly.
> The actual pulse width necessary for your
> application must be determined
> based on power required, power available at what
> speed and load. Individual
> motors operate differently so, often, it is best to
> just try something as a
> starting point (50%) and adjust as necessary.
>
> Jim
>
>
Original Message
> From: Pieter-Jan van Diepen
> [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=4zdmYm38_uCDEIdnkvWlWkRthmsYFK9SP8W-OF0rXdYz-y9ghQhg5AwZpyxeITiNZ0Im7U-fUEzz5w]diepenpj@h...[/url
> Sent: Monday, March 10, 2003 4:49 AM
> To: basicstamps@yahoogroups.com
> Subject: [noparse][[/noparse]basicstamps] pwm frequency
>
>
> Hello all,
>
> I want to run a motor with pwm,so i can alter the
> speed. how can i determine
> a good frequency and the good pulse/pause or is the
> up time equal to the
> downtime?
>
> I thought that i read somewhere that if the
> frequency to low
> (or to high???) the motor becomes hot (if it isn't
> turning)
>
> greetings pieter-jan
>
>
>
>
>
>
_________________________________________________________________
> Add photos to your messages with MSN 8. Get 2 months
> FREE*.
> http://join.msn.com/?page=features/featuredemail
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>
> To UNSUBSCRIBE, just send mail to:
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> Text in the Subject and
> Body of the message will be ignored.
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> http://docs.yahoo.com/info/terms/
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> To UNSUBSCRIBE, just send mail to:
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I'm running a 24 Volt Permanent magnet motor of about 90 watts with PWM
at 20KHZ, with a duty cycle of between 5 - 95 %. I do not have a problem
with over heating (unless I overload the motor) :-), and at 20KHZ audio
noise is not a problem. The PWM output on as stamp, I believe, is meant
for measuring RC timing I think. You might have a problem with other
parts of your program "messing up" the pulse timing to your motor when
using "pulse out" and "pause" statements. I resorted to using a PIC with
a dedicated HPWM channel to overcome my problems. Different motors
though have different characteristics, so you will have to experiment. A
good link for motor control is:- http://www.4qd.co.uk/
HTH
Rob
Original Message
From: Pieter-Jan van Diepen [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=sfCFLUG0TjnNWdyhLRQ5uZV0P0xo0bW39YCmW0VWKj8lPKQkQJhvc-bRcS2kAkNE7PGfl9FD89zOr0Y]diepenpj@h...[/url
Sent: 10 March 2003 09:49
To: basicstamps@yahoogroups.com
Subject: [noparse][[/noparse]basicstamps] pwm frequency
Hello all,
I want to run a motor with pwm,so i can alter the speed. how can i
determine
a good frequency and the good pulse/pause or is the up time equal to the
downtime?
I thought that i read somewhere that if the frequency to low
(or to high???) the motor becomes hot (if it isn't turning)
greetings pieter-jan
_________________________________________________________________
Add photos to your messages with MSN 8. Get 2 months FREE*.
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What is the PWM frequency on a BS2? Does it vary with different Stamps?
Sid Weaver
I2C on a BS2 platform.................
http://www.visualmuses.com/chipcircuit/index.html
[noparse][[/noparse]Non-text portions of this message have been removed]
111.3 kilohertz at duty=128. Here is more info on the inner
workings...
http://www.emesystems.com/BS2PWM.htm
That is for the BS2 and BS2e specifically. Also read the discussion
in the Stamp manual.
>For Jon Williams:
>
>What is the PWM frequency on a BS2? Does it vary with different Stamps?
>
>Sid Weaver
>I2C on a BS2 platform.................
>http://www.visualmuses.com/chipcircuit/index.html
>