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Anonymous Poster

Stepper Motors and Specifications for Step Angles

02/11/2008 7:07 AM

hi,

I have to use a stepper motor to rotate a component of 100kg at 5 rpm.

what are the specifications step angles shall i need

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Guru

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#1

Re: stepper motor

02/11/2008 7:58 AM

What is the moment of inertia of your load?

What is the required smoothness?

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Anonymous Poster
#8
In reply to #1

Re: stepper motor

02/12/2008 1:17 AM

hi,

may i know wat exactly momemt of inertia.

it's for component or for motor

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Anonymous Poster
#9
In reply to #1

Re: stepper motor

02/12/2008 2:21 AM

hi, I have to use a stepper motor for lathe head stock to rotate 100 kg crank shaft with 5 rpm.wat type of motor i have to choose and what are the req

moment of inertia is 0.25 kg-m.

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#2

Re: Stepper Motors and Specifications for Step Angles

02/11/2008 2:08 PM

Are my eyes deceiving me?

I am sure I've seen this topic posted on several other groups?

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Guru

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#3
In reply to #2

Re: Stepper Motors and Specifications for Step Angles

02/11/2008 2:20 PM

Either this one or very similar. Anyway, everytime I see this I ask about inertia and I never get an answer.

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Guru
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#4
In reply to #3

Re: Stepper Motors and Specifications for Step Angles

02/11/2008 2:25 PM

Hmmm methinks this may be homework related, perhaps?

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Anonymous Poster
#7
In reply to #3

Re: Stepper Motors and Specifications for Step Angles

02/12/2008 1:14 AM

hey what is the meaning of inertia

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Anonymous Poster
#10
In reply to #3

Re: Stepper Motors and Specifications for Step Angles

02/12/2008 2:32 AM

hi, I have to use a stepper motor for lathe head stock to rotate 100 kg crank shaft with 5 rpm.wat type of motor i have to choose and what are the req

moment of inertia is 0.25 kg-m.

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#5

Re: Stepper Motors and Specifications for Step Angles

02/11/2008 2:55 PM

I am a component of about 100kg and I rotate without a stepper.

Serious now.

Are you allowed to use a drive? (gears / pulleys).

What are you going to use for a driver?

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Anonymous Poster
#11
In reply to #5

Re: Stepper Motors and Specifications for Step Angles

02/12/2008 2:38 AM

hi,

is it necessary to use a pulley/gear mechanism. if required tell me how to approach

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#13
In reply to #11

Re: Stepper Motors and Specifications for Step Angles

02/12/2008 2:17 PM

I am guessing that6 the reason for using a stepper is that you want to cut a spiral groove or a oval shaped shaft.

The mechanical driver may still be your best option.

A stepper at 5rpm is a bad idea.

The best torque on a stepper will be at full steps. at 1.8 deg/step (200 steps / rev) 16 steps / sec. is too slow.

A pulley or gear drive will increase the rate of the stepper and torque on the 100 kg shaft.

If you really have too you must also consider a servo with an encoder.

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Anonymous Poster
#18
In reply to #13

Re: Stepper Motors and Specifications for Step Angles

02/14/2008 7:42 AM

Hai,

Will u suggest the Variable frequency drive is suitable for the applications as said earlier. Also what would be the output torque when we are connecting motor at rpm1400 approx to an output rpm we require is 7?hp of motor=1hp

Can we run 100kg crankshaft between centres by means of frictional transmission of power given to the live centre. and to be run 7 rpm.

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Guru

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#6

Re: Stepper Motors and Specifications for Step Angles

02/11/2008 8:56 PM

Why the stepper?!? What about a DC motor with feedback? A 100kg load is a killer for stepping, when you seem to need rotation. If precision of angle is needed, DC + Shaft encoder gives all the accuracy you might require.

If you think, A stepper will get you the precise angle under load, you are dreaming. A dynamically overloaded stepper will slip and slip again, leaving you in the dark.

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#12

Re: Stepper Motors and Specifications for Step Angles

02/12/2008 7:04 AM

5 rpm? Why that speed on a lathe? Why a stepper motor on a lathe? Give us some details, please.

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Anonymous Poster
#14
In reply to #12

Re: Stepper Motors and Specifications for Step Angles

02/13/2008 12:28 AM

hi,

why 5 rpm means we are using this set up for crankshaft testing to check runouts etc.

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Anonymous Poster
#15
In reply to #12

Re: Stepper Motors and Specifications for Step Angles

02/13/2008 4:04 AM

hi,

why 5 rpm means we are using this set up for crankshaft testing to check runouts etc. If it is not possible give a solution which will suitable for my set up.

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Anonymous Poster
#19
In reply to #12

Re: Stepper Motors and Specifications for Step Angles

02/15/2008 4:44 AM

hi,

why 5 rpm means because i am asking is at the top of the machine a rod having dial gauges which takes reading while the crank shaft is running and it checks the runouts.

If i cant load 100 kg crank shaft directly on the motor will u suggest any gear mechanism to achieve that speed and to share the torque

will u suggest variable frequency drive is the better one.

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#16

Re: Stepper Motors and Specifications for Step Angles

02/13/2008 4:41 AM

As I keep reading this thread, a chill goes down my spine. A power rotation of an unbalanced large object, and a technician getting close with any instrument is asking for trouble and accidents. Machine shops do measurement with a tabletop testfixture with no power equipment nearby for a reason. I, for one, would not get my micrometer near to a power rotated object for anything!!!

What this guy is asking for, is trouble. Unless he can AMPLY clarify, thats it.

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Anonymous Poster
#17
In reply to #16

Re: Stepper Motors and Specifications for Step Angles

02/13/2008 10:18 AM

hi,

why because i am asking is at the top of the machine a rod having dial gauges which takes reading while the crank shaft is running and it checks the runouts.

why power means i want to make it as automatic rather hand rotation

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