Powering 12vdc stepper motor with 7.2v battery...
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Posts: 46,084
Can I do this.
Can I amplify the voltage with a tranistor. I would hate to have to
add 8 AA batteries just to power the turret for the cam.
Thanks.
Can I amplify the voltage with a tranistor. I would hate to have to
add 8 AA batteries just to power the turret for the cam.
Thanks.
Comments
in short bursts to turn a turret that the camera is going to be on.
it can not harm, the only problem are:
a reduction of the torque
a lowering of the available ramp ability
Regards
ECO
Original Message
From: "nestlerv" <nestlerv@a...>
To: <basicstamps@yahoogroups.com>
Sent: Tuesday, July 29, 2003 3:28 PM
Subject: [noparse][[/noparse]basicstamps] Powering 12vdc stepper motor with 7.2v battery...
> Is there a way that I can do this? The motor is only going to be used
> in short bursts to turn a turret that the camera is going to be on.
>
>
>
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motor and the precision of the movement is important, I dont want to
play with trying to use almost half the voltage.
--- In basicstamps@yahoogroups.com, "ECO" <ecourt@b...> wrote:
> Try it.
> it can not harm, the only problem are:
> a reduction of the torque
> a lowering of the available ramp ability
> Regards
> ECO
>
Original Message
> From: "nestlerv" <nestlerv@a...>
> To: <basicstamps@yahoogroups.com>
> Sent: Tuesday, July 29, 2003 3:28 PM
> Subject: [noparse][[/noparse]basicstamps] Powering 12vdc stepper motor with 7.2v
battery...
>
>
> > Is there a way that I can do this? The motor is only going to be
used
> > in short bursts to turn a turret that the camera is going to be
on.
> >
> >
> >
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
> > from the same email address that you subscribed. Text in the
Subject and Body of the message will be ignored.
> >
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> > Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/
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> >
> >
practice to run steppers at 5 times the recommended voltage. Typically a
stepper driver is sending 'pulses' to the stepper so the voltage is like
PWM. I am currently running 3 steppers in a CNC mill at 24v which are
rated at 5v. Give it a try at 7.2v and see what happens. A great stepper
explanation can be found at:
http://www.cs.uiowa.edu/~jones/step/types.html There are some cheap
steppers at Jameco.
Is there a way that I can do this? The motor is only going to be used
in short bursts to turn a turret that the camera is going to be on.
To UNSUBSCRIBE, just send mail to:
basicstamps-unsubscribe@yahoogroups.com
from the same email address that you subscribed. Text in the Subject and
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> Is there a way that I can do this? The motor is only going to be
used
> in short bursts to turn a turret that the camera is going to be on.
try it with 7.2 volts. you will not get the speed but then if you
are not concerned with high speed, who cares.
also the amps are the issue. do not exceed the amps on the motor,
but do not de-rate just becuase you are using a lower voltage.
lastly, since you may not care about speed, considder using a half
coil (center tap to one end) on a 6 wire stepper and use an H-
bridge. that requires use of half nameplate amps and will save
battery power.
As a note steppers have nameplate listing for engineering reasons,
not connection reasons. using a chopper driver with 5 to 20 times
nameplate voltage will offer the rated performance. check the
manufactures specs. that 7.2 volt motor should have graphed
characteristics with 48 volt power.
Dave
> Is there a way that i can amplify it to 12v? Since it is a stepper
> motor and the precision of the movement is important, I dont want
to
> play with trying to use almost half the voltage.
better check out how a stepper works. the nameplate is not the
applied use, but the basis of design for the use.
7.2 volts at 1.5 amps = 10.8 watts.
at 70 volts, your chopper driver would deliver 10.8 only be on 1/10
the time, but the motor speed would be much faster than at 7.2 volts.
also the power delivered would be much greater.
Regardless of voltage, one step is one step. accuracy will not
change with voltage, but power will. you may lose or miss steps if
you under-volt or under power a stepper or use too small a stepper
for the required troque.
Also, check for a lower voltage stepper. they should be readily
available out of used equipment or surplus.
Dave
> I'm by no means a stepper motor expert, but I understood that it is
common
> practice to run steppers at 5 times the recommended voltage.
This is partially correct. at 5 times the voltage the injection of
current makes the motor rotate with more force. it makes it snap.
at voltages over 25 times nameplate, the coils begin to saturate and
losses begin to appear.
the chopper drivers monitor current and contorl the pulse so that
nameplate current is not exceeded. A simple way to think about it is
watts. how long will it take to deliver 10 watts with a 1 amp
circuit at 7.2 volts ? how long at 48 volts ? The faster rise
times means a faster motor and more power.
in the hobby uniploar drivers many are set for nameplate voltages so
one cannot just up the voltages without repercussions. Unipolar
drivers that use a limiting resistor start to waste power in the high
wattage needed. At some point, the heat or waste requires going to a
chopper driver.
Typically a
> stepper driver is sending 'pulses' to the stepper so the voltage is
like
> PWM.
this is a good description. the pwm is based on watts.
> I am currently running 3 steppers
> in a CNC mill at 24v which are
> rated at 5v.
This is typical. using lower voltage motors will offer some
additonal power, and using a higher supply voltage (if the driver can
handle it) will boost power and higher rapid speeds.
Give it a try at 7.2v and see what happens. A great stepper
> explanation can be found at:
> http://www.cs.uiowa.edu/~jones/step/types.html
good introduction to steppers
> There are some cheap
> steppers at Jameco.
>
>
>
>
> Is there a way that I can do this? The motor is only going to be
used
> in short bursts to turn a turret that the camera is going to be on.
>
>
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the
Subject and
> Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/
motor require? (If you just know the winding resistances, the current can
be determined.)
You could use 4 rechargeable AA cells to give you 4.8 volts, and connect
them in series with your main battery pack. In other words, the negative
connection from your 4-AA cell pack would go to the positive side of your
main battery pack, and the positive connection of the 4-AA cell pack would
provide 12 volts (relative to ground) for your stepper motor. Anything
connected between ground and the positive side of the 4-AA pack would "see"
12 volts, since both battery packs are in series and the voltage adds. If
AA cells don't provide enough energy, larger cells could be used instead.
Depending on the amount of power needed for the stepper and how often it is
used, you might even be able to get by with smaller/lighter AAA cells.
There are circuits that could boost the 7.2 volts to 12 volts, but with the
amount of current you probably need it would probably be more costly and
complex than just using the 4 additional cells.
Randy
www.glitchbuster.com
Original Message
From: "nestlerv" <nestlerv@a...>
To: <basicstamps@yahoogroups.com>
Sent: Tuesday, July 29, 2003 7:46 AM
Subject: [noparse][[/noparse]basicstamps] Re: Powering 12vdc stepper motor with 7.2v battery...
> Is there a way that i can amplify it to 12v? Since it is a stepper
> motor and the precision of the movement is important, I dont want to
> play with trying to use almost half the voltage.
>
>
>
> --- In basicstamps@yahoogroups.com, "ECO" <ecourt@b...> wrote:
> > Try it.
> > it can not harm, the only problem are:
> > a reduction of the torque
> > a lowering of the available ramp ability
> > Regards
> > ECO
> >
Original Message
> > From: "nestlerv" <nestlerv@a...>
> > To: <basicstamps@yahoogroups.com>
> > Sent: Tuesday, July 29, 2003 3:28 PM
> > Subject: [noparse][[/noparse]basicstamps] Powering 12vdc stepper motor with 7.2v
> battery...
> >
> >
> > > Is there a way that I can do this? The motor is only going to be
> used
> > > in short bursts to turn a turret that the camera is going to be
> on.
> > >
> > >
> > >
> > >
> > > To UNSUBSCRIBE, just send mail to:
> > > basicstamps-unsubscribe@yahoogroups.com
> > > from the same email address that you subscribed. Text in the
> Subject and Body of the message will be ignored.
> > >
> > >
> > > Your use of Yahoo! Groups is subject to
> http://docs.yahoo.com/info/terms/
> > >
> > >
> > >
> > >
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
>
>
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>
>
Well, I am using the 12v stepper motor from the parallax site along
with the darlington chip to control it. For now i dont really care
about the speed. I dont even have the motor yet because it is on back
order. I am trying to get the theory down and the schematics in order
so I can get it going as soon as possible.
I currently have a 3000 ma/hour battery attached. I am planning on
putting a second one in parallel so that I will effectively have 6000
ma/hour 7.2v power source for the bot.
I thought that perhaps the same way Randy suggested using a
transistor to up the voltage to trigger the mosfet could be the same
technique to use for driving the motor.
Couldnt i use a transitor to amplify the voltage to the motor?
--- In basicstamps@yahoogroups.com, "Randy Jones" <randyjones@w...>
wrote:
> Here's something that could work. BTW, how much current does your
stepper
> motor require? (If you just know the winding resistances, the
current can
> be determined.)
>
> You could use 4 rechargeable AA cells to give you 4.8 volts, and
connect
> them in series with your main battery pack. In other words, the
negative
> connection from your 4-AA cell pack would go to the positive side
of your
> main battery pack, and the positive connection of the 4-AA cell
pack would
> provide 12 volts (relative to ground) for your stepper motor.
Anything
> connected between ground and the positive side of the 4-AA pack
would "see"
> 12 volts, since both battery packs are in series and the voltage
adds. If
> AA cells don't provide enough energy, larger cells could be used
instead.
> Depending on the amount of power needed for the stepper and how
often it is
> used, you might even be able to get by with smaller/lighter AAA
cells.
>
> There are circuits that could boost the 7.2 volts to 12 volts, but
with the
> amount of current you probably need it would probably be more
costly and
> complex than just using the 4 additional cells.
>
> Randy
>
> www.glitchbuster.com
>
>
>
Original Message
> From: "nestlerv" <nestlerv@a...>
> To: <basicstamps@yahoogroups.com>
> Sent: Tuesday, July 29, 2003 7:46 AM
> Subject: [noparse][[/noparse]basicstamps] Re: Powering 12vdc stepper motor with 7.2v
battery...
>
>
> > Is there a way that i can amplify it to 12v? Since it is a stepper
> > motor and the precision of the movement is important, I dont want
to
> > play with trying to use almost half the voltage.
> >
> >
> >
> > --- In basicstamps@yahoogroups.com, "ECO" <ecourt@b...> wrote:
> > > Try it.
> > > it can not harm, the only problem are:
> > > a reduction of the torque
> > > a lowering of the available ramp ability
> > > Regards
> > > ECO
> > >
Original Message
> > > From: "nestlerv" <nestlerv@a...>
> > > To: <basicstamps@yahoogroups.com>
> > > Sent: Tuesday, July 29, 2003 3:28 PM
> > > Subject: [noparse][[/noparse]basicstamps] Powering 12vdc stepper motor with 7.2v
> > battery...
> > >
> > >
> > > > Is there a way that I can do this? The motor is only going to
be
> > used
> > > > in short bursts to turn a turret that the camera is going to
be
> > on.
> > > >
> > > >
> > > >
> > > >
> > > > To UNSUBSCRIBE, just send mail to:
> > > > basicstamps-unsubscribe@yahoogroups.com
> > > > from the same email address that you subscribed. Text in the
> > Subject and Body of the message will be ignored.
> > > >
> > > >
> > > > Your use of Yahoo! Groups is subject to
> > http://docs.yahoo.com/info/terms/
> > > >
> > > >
> > > >
> > > >
> >
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
> > from the same email address that you subscribed. Text in the
Subject and
> Body of the message will be ignored.
> >
> >
> > Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/
> >
> >
primarily 'current' amplification devices,
not voltage. The current entering the 'Base'
lead to the Emitter results in additional
current flowing from the Collector to the
Emitter lead -- as long as the transistor
is 'forward biased' -- the Collector is more
positive in voltage than the Base, which
is more positive than the Emitter.
If all you have is a +7.2 Volt DC power
supply, getting 12 volts DC out of it takes
more than just a transistor.
There are DC to DC converter DIP modules
out there -- you may want to search on
that.
--- In basicstamps@yahoogroups.com, "nestlerv" <nestlerv@a...> wrote:
> Hmmm,
>
> Well, I am using the 12v stepper motor from the parallax site along
> with the darlington chip to control it. For now i dont really care
> about the speed. I dont even have the motor yet because it is on
back
> order. I am trying to get the theory down and the schematics in
order
> so I can get it going as soon as possible.
>
> I currently have a 3000 ma/hour battery attached. I am planning on
> putting a second one in parallel so that I will effectively have
6000
> ma/hour 7.2v power source for the bot.
>
> I thought that perhaps the same way Randy suggested using a
> transistor to up the voltage to trigger the mosfet could be the
same
> technique to use for driving the motor.
>
> Couldnt i use a transitor to amplify the voltage to the motor?
>
>
>
>
>
>
>
>
>
>
>
>
> --- In basicstamps@yahoogroups.com, "Randy Jones" <randyjones@w...>
> wrote:
> > Here's something that could work. BTW, how much current does
your
> stepper
> > motor require? (If you just know the winding resistances, the
> current can
> > be determined.)
> >
> > You could use 4 rechargeable AA cells to give you 4.8 volts, and
> connect
> > them in series with your main battery pack. In other words, the
> negative
> > connection from your 4-AA cell pack would go to the positive side
> of your
> > main battery pack, and the positive connection of the 4-AA cell
> pack would
> > provide 12 volts (relative to ground) for your stepper motor.
> Anything
> > connected between ground and the positive side of the 4-AA pack
> would "see"
> > 12 volts, since both battery packs are in series and the voltage
> adds. If
> > AA cells don't provide enough energy, larger cells could be used
> instead.
> > Depending on the amount of power needed for the stepper and how
> often it is
> > used, you might even be able to get by with smaller/lighter AAA
> cells.
> >
> > There are circuits that could boost the 7.2 volts to 12 volts,
but
> with the
> > amount of current you probably need it would probably be more
> costly and
> > complex than just using the 4 additional cells.
> >
> > Randy
> >
> > www.glitchbuster.com
> >
> >
> >
Original Message
> > From: "nestlerv" <nestlerv@a...>
> > To: <basicstamps@yahoogroups.com>
> > Sent: Tuesday, July 29, 2003 7:46 AM
> > Subject: [noparse][[/noparse]basicstamps] Re: Powering 12vdc stepper motor with 7.2v
> battery...
> >
> >
> > > Is there a way that i can amplify it to 12v? Since it is a
stepper
> > > motor and the precision of the movement is important, I dont
want
> to
> > > play with trying to use almost half the voltage.
> > >
> > >
> > >
> > > --- In basicstamps@yahoogroups.com, "ECO" <ecourt@b...> wrote:
> > > > Try it.
> > > > it can not harm, the only problem are:
> > > > a reduction of the torque
> > > > a lowering of the available ramp ability
> > > > Regards
> > > > ECO
> > > >
Original Message
> > > > From: "nestlerv" <nestlerv@a...>
> > > > To: <basicstamps@yahoogroups.com>
> > > > Sent: Tuesday, July 29, 2003 3:28 PM
> > > > Subject: [noparse][[/noparse]basicstamps] Powering 12vdc stepper motor with 7.2v
> > > battery...
> > > >
> > > >
> > > > > Is there a way that I can do this? The motor is only going
to
> be
> > > used
> > > > > in short bursts to turn a turret that the camera is going
to
> be
> > > on.
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > To UNSUBSCRIBE, just send mail to:
> > > > > basicstamps-unsubscribe@yahoogroups.com
> > > > > from the same email address that you subscribed. Text in
the
> > > Subject and Body of the message will be ignored.
> > > > >
> > > > >
> > > > > Your use of Yahoo! Groups is subject to
> > > http://docs.yahoo.com/info/terms/
> > > > >
> > > > >
> > > > >
> > > > >
> > >
> > >
> > > To UNSUBSCRIBE, just send mail to:
> > > basicstamps-unsubscribe@yahoogroups.com
> > > from the same email address that you subscribed. Text in the
> Subject and
> > Body of the message will be ignored.
> > >
> > >
> > > Your use of Yahoo! Groups is subject to
> http://docs.yahoo.com/info/terms/
> > >
> > >
> Hmmm,
>
> Well, I am using the 12v stepper motor from the parallax site along
> with the darlington chip to control it. For now i dont really care
> about the speed. I dont even have the motor yet because it is on
back
> order. I am trying to get the theory down and the schematics in
order
> so I can get it going as soon as possible.
>
> I currently have a 3000 ma/hour battery attached. I am planning on
> putting a second one in parallel so that I will effectively have
6000
> ma/hour 7.2v power source for the bot.
>
> I thought that perhaps the same way Randy suggested using a
> transistor to up the voltage to trigger the mosfet could be the
same
> technique to use for driving the motor.
>
> Couldnt i use a transitor to amplify the voltage to the motor?
>
Before you get creative on fixing a problem, see if it really is a
problem.
the 7.2 v may work fine.
the motor will not work eratic unless it is just underpowered in
torque.
Make sure the load is smooth and does not bind in it's operation.
also, if you have the ability, make sure it is balanced over the axis
to there is no undue power requirement.
If it does become a problem and you can add a second battery, then
you could have 14.4 volts and use that directly. Don't bother to
regulate that as you will be wasting power in the regulation.
Dave
You may be on to something. I will have a second battery. The second
battery is intended to be for extending the time the robot can get
around so it is in parallel for more currnt.
do you think there is a way that i can hook up the second battery so
that certain components will draw current from them in parallel and
then the stepper motor can draw from them in series. That would be
best.
Thanks
--- In basicstamps@yahoogroups.com, "Dave Mucha" <davemucha@j...>
wrote:
> --- In basicstamps@yahoogroups.com, "nestlerv" <nestlerv@a...>
wrote:
> > Hmmm,
> >
> > Well, I am using the 12v stepper motor from the parallax site
along
> > with the darlington chip to control it. For now i dont really
care
> > about the speed. I dont even have the motor yet because it is on
> back
> > order. I am trying to get the theory down and the schematics in
> order
> > so I can get it going as soon as possible.
> >
> > I currently have a 3000 ma/hour battery attached. I am planning
on
> > putting a second one in parallel so that I will effectively have
> 6000
> > ma/hour 7.2v power source for the bot.
> >
> > I thought that perhaps the same way Randy suggested using a
> > transistor to up the voltage to trigger the mosfet could be the
> same
> > technique to use for driving the motor.
> >
> > Couldnt i use a transitor to amplify the voltage to the motor?
> >
>
>
> Before you get creative on fixing a problem, see if it really is a
> problem.
>
> the 7.2 v may work fine.
>
> the motor will not work eratic unless it is just underpowered in
> torque.
>
> Make sure the load is smooth and does not bind in it's operation.
>
> also, if you have the ability, make sure it is balanced over the
axis
> to there is no undue power requirement.
>
> If it does become a problem and you can add a second battery, then
> you could have 14.4 volts and use that directly. Don't bother to
> regulate that as you will be wasting power in the regulation.
>
> Dave