Calculation of time taken for a motor to rotate an object 360 degrees

[physicsguy113]

Homework Statement

https://media.digikey.com/pdf/Data%20Sheets/Makeblock%20PDFs/80047_Web.pdf

Relevant Equations

V=IR
SUVAT
Speed= distance/time

How would I go about calculating the time taken for the motor on page 2 to move the attached beam 360 degrees?

Things such as the rpm and voltage are given in the attached data sheet for various different motors and you can reference anyone you like. I'm more interested in understanding what's going on.

I want to understand how to work out the question.
e.g. What equations do I need to use. Do I need any extra information before I can fully answer my above question.
So far I'm thinking I need to use the rpm, voltage and maybe the gear ratio( but I'm not entirely sure what that is!) Any help or hints would be appreciated.

https://media.digikey.com/pdf/Data%20Sheets/Makeblock%20PDFs/80047_Web.pdf

 

[kuruman]

Welcome to PF @physicsguy113.


According to our rules, you need to show some effort towards the answer before receiving help.

 

[physicsguy113]

Oh ok,
Sorry, I'm new to this forum!

For the 185rpm motor with a gear ratio of 1:45. I would calculate the time taken for the motor to rotate 360 degrees as: ((185/45)/60)*360 = 24.6s to turn 360 degrees. Is this correct. If so great! If not where have I gone wrong?

 

[kuruman]

The 185 rpm motor shaft makes one revolution or turns by 360^o every 60/185 seconds.
As I understand it, a gear ratio of 1:45 means that the driven gear makes 45 revolutions for every one revolution of the driver gear. So the time it takes for the driven gear to make one revolution or turn by 360^o is (1/45)th of 60/185 seconds.

 

[Lnewqban]

Welcome, physicsguy113!

Please, note that the pictures show no beam to be rotated by the motor, but what they call a “DC Motor-25 Bracket”, which a support for the body of the motor, leaving theshaft free to rotate.

I may be wrong, but it seems to me that the shown 16 rpm are the actual rotational speed of the shaft you see in the pictures.

This is an assembly of an electric motor and a planetary gear box that reduces the rotational speed coming from the motor, providing an increased torque of the output shaft.

The show table lists motors that rotate in the ball park of 700 rpm each.
You can see that the listed reduction and shaft speed are related to a number close to 700 for all the options.

 

[physicsguy113]

Welcome, physicsguy113!

Please, note that the pictures show no beam to be rotated by the motor, but what they call a “DC Motor-25 Bracket”, which a support for the body of the motor, leaving theshaft free to rotate.

I may be wrong, but it seems to me that the shown 16 rpm are the actual rotational speed of the shaft you see in the pictures.

This is an assembly of an electric motor and a planetary gear box that reduces the rotational speed coming from the motor, providing an increased torque of the output shaft.

The show table lists motors that rotate in the ball park of 700 rpm each.
You can see that the listed reduction and shaft speed are related to a number close to 700 for all the options.

Oh yeah, the reason I mentioned rotating a beam is because I am working on a project and have designed a component which would be rotated by the 185RPM model motor. Therefore, I was wondering how do I take into account the weight/size of the object the motor will be rotating in order to work out the time taken for one revolution of my component, or is this not necessary?

Also, thanks for all the responses so far. It's really helpful to have different ideas to consider and also clarify some of my thoughts too!

 

[Lnewqban]

Oh yeah, the reason I mentioned rotating a beam is because I am working on a project and have designed a component which would be rotated by the 185RPM model motor. Therefore, I was wondering how do I take into account the weight/size of the object the motor will be rotating in order to work out the time taken for one revolution of my component, or is this not necessary?

Also, thanks for all the responses so far. It's really helpful to have different ideas to consider and also clarify some of my thoughts too!

I have no experience working with this type of motors; soon you will see more posts from more experienced members.
I don't know how this type reacts to resistive forces and torques, which are the main things to consider in your mechanism and for different stages of the overall movement.

For example, if your beam must be rotated from a state of repose to certain constant speed, its angular inertia will induce a resistive torque during certain period of time.
During that transitional time, the rotational speed of the shaft may or may not be significantly reduced.