Torque meter idea needed
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Posts: 46,084
Does anyone have a simple way to measure the amount of torque needed to
turn an object. In this case the takeup reel on a camera.
I'm working on a project that will use a BS2 to spin two steppers, but I
need to know how much torque is needed.
David
turn an object. In this case the takeup reel on a camera.
I'm working on a project that will use a BS2 to spin two steppers, but I
need to know how much torque is needed.
David
Comments
David@C... writes:
> Does anyone have a simple way to measure the amount of torque needed to
> turn an object. In this case the takeup reel on a camera.
>
> I'm working on a project that will use a BS2 to spin two steppers, but I
> need to know how much torque is needed.
>
I mechanical tool called a torque wrench is available. I don't know what
ranges the come in. Another do-it yourself way is to attach an 1-inch arm to
the
shaft of the reel. At the end of the 1-inch shaft suspend a weight beginning
with about 1 ounce, and see how much weight it take to start turning the
reel. The point at which it starts to trun is the "holding torque".
If you can determine the oz/inch torque, you can convert it to gms/cm, which
is the way most steppers are labeled.
Sid Weaver
W4EKQ
Port Richey, FL
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David@C... writes:
Does anyone have a simple way to measure the amount of torque needed to
turn an object. In this case the takeup reel on a camera.
I'm working on a project that will use a BS2 to spin two steppers, but I
need to know how much torque is needed.
David
David,
You use a "beam" type torque wrench. the link shown is overkill but you will
get the idea.
http://www.epinions.com/hmgd-Shop_Tools-All-Craftsman_Beam_Torque_Wrench_44642
#
Or, you can device your own.....
If an arm that is 1 foot long is connected to the center of the rotating
device, and at the end of the arm is a 1 pound weight, and the device will just
start to turn, then you have 1 foot pound. This would be with the arm's starting
position parallel to the ground. Any other position would require a cosine
factor to be involved....you can probably get a rough idea using a 6 inch arm
and some fishing weights...as in....
....there are derivatives to this, as in inch/ounces. That is an arm so many
inches long with so many ounces on the end of it.....
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writes:
I mechanical tool called a torque wrench is available. I don't know what
ranges the come in. Another do-it yourself way is to attach an 1-inch arm to
the
shaft of the reel. At the end of the 1-inch shaft suspend a weight beginning
with about 1 ounce, and see how much weight it take to start turning the
reel. The point at which it starts to trun is the "holding torque".
If you can determine the oz/inch torque, you can convert it to gms/cm, which
is the way most steppers are labeled.
Sid Weaver
W4EKQ
Port Richey, FL
YEP!!!
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> Does anyone have a simple way to measure the amount of torque
needed to
> turn an object. In this case the takeup reel on a camera.
>
> I'm working on a project that will use a BS2 to spin two steppers,
but I
> need to know how much torque is needed.
>
> David
Hi David,
Stepper motors are rated in ounce/inches.
the idea of a lever with weight is a simple method, just use one inch
and not one foot.
and the arm must be level to the earth, not on an angle.
hang a cup and drop water in the cup until you get movement.
weight the cup. postal scale ?
re-test with weights.
also, if you expect to use some type of gearing or screws or
something, allow for friction losses. I would considder 4 times you
weight as good as gearing could have 70% losses due to friction, and
at 4 times, you should be way under powered for causing damage.
Dave
pots resistance. Use a spring or rubber band to counteract the torque needed
to pull the arm down.
0 ohms would be contracted spring. When the torque moves the arm lower, a
higher resistance would be a higher ohm reading. The spring of course than
pulls the arm back to zero with a lower torque.
-kerry
At 06:32 PM 8/21/03 -0000, you wrote:
>--- In basicstamps@yahoogroups.com, David Clarke <David@C...> wrote:
>> Does anyone have a simple way to measure the amount of torque
>needed to
>> turn an object. In this case the takeup reel on a camera.
>>
>> I'm working on a project that will use a BS2 to spin two steppers,
>but I
>> need to know how much torque is needed.
>>
>> David
>
>Hi David,
>
>Stepper motors are rated in ounce/inches.
>
>the idea of a lever with weight is a simple method, just use one inch
>and not one foot.
>
>and the arm must be level to the earth, not on an angle.
>
>hang a cup and drop water in the cup until you get movement.
>weight the cup. postal scale ?
>
>re-test with weights.
>
>also, if you expect to use some type of gearing or screws or
>something, allow for friction losses. I would considder 4 times you
>weight as good as gearing could have 70% losses due to friction, and
>at 4 times, you should be way under powered for causing damage.
>
>Dave
>
>
>
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