# What is Rotary: Definition and 90 Discussions

Rotary International is an international service organization whose stated purpose is to bring together business and professional leaders in order to provide humanitarian service and to advance goodwill and peace around the world. It is a non-political and non-religious organization open to all. There are over 35,000 member clubs worldwide, with a membership of 1.2 million individuals, known as Rotarians.

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1. ### Solving Rotary Friction Problem at Ye Olde Swinging Door

Homework Statement: A door opened at 75 degrees from the latch remains at rest. When moved to a position 60 degrees from the latch, it slowly closes on its own. Is there another possible cause besides a sloping floor? Relevant Equations: \tau = r x F; v = \omega x r; a_T = \alpha x r, where...
2. ### Mechanism Ideas for: Rotary Action-input Pump?

I'm trying to come up with a design for a handheld pump that will be used to suck diesel from a car's fuel tank. There's definitely going to be a pipe dipping into the fuel tank, and there's definitely going to be a human manually operating the pump. I'm trying to think of a mechanism that...
3. ### Engineering First order differential equations (movement of a rotary solenoid)

My question i am trying to solve: I have successfully done first order equations before but this one has got me a little stuck. My attempt at the general solution below: $${5} \frac{\text{d}\theta}{\text{d}t}=-6\theta$$ $${5} \frac{\text{d}\theta}{\text{d}t} =\frac{\text{-6}\theta}{5}$$...
4. ### Rotary Vane Vacuum Pump Question

So in the image below from a video I watched , the narrator states “gas pressure from the refrigerator rushes into the low-pressure chamber “ So, I do understand that gas will push its way into a low-pressure area from a high-pressure (high to low)….but what I am unclear of is to how that...
5. ### Physics History (Maxwell) Rotary Vectors?

I am reading the text 'Innovations in Maxwell's Electromagnetic Theory'. on page 44 there is a discussion on Ampere's circuital law . The passage is below. I don't understand the final statement. "In general represent a kind of relationship that obtains between certain pairs of phenomena , of...
6. ### Modeling impact forces in rotary motion

Hi, how can I calculate the impact force in case when some object is in uniform circular motion and then suddenly hits the target. For example consider lawn mower's blade hitting stone or drum woodchipper's blade hitting branch. Both blades are already moving at full speed when they hit the...
7. ### AC motor rotary capacitor soft start

I was wondering about , have there been or are there any systems that would use a large capacitance rotary capacitor/s as a mechanism for soft start of larger AC motors and also they would serve as power factor correction devices? The idea is basically simple, say one has a 3 phase motor and we...
8. ### How to determine the power of a rotary lobe pump?

Want to know how to get the actual power the pump needs. I can measure the flow rate by the flow meter and count the revolutions of the pump. But selecting the proper motor for the pump would be a problem. So I want to know how to determine the power of the rotary lobe pump and generate the...
9. ### Appliances How to modify a rotary pencil sharpener to sharpen off-center leads?

When inexpensive pencils are sharpened in rotary pencil sharpeners, the result is often a pencil point that has a long sliver of wood running along one side of it. I think this is due to the pencil lead being off center in the pencil. Turning the pencil while sharpening it usually doesn't fix...
10. ### What is making this sound? (in a Rotary lobe pump)

What is the reason making this sound?? ( Rotary lobe pump)
11. ### Rotary motion to lift a dump truck

Homework Statement In my robotics class I was task with creating a robot to lift and house objects, I have the lifting mechanism, and a housing area, but I can't figure how to get the bucket of the robot to dump using a rotary motor. Homework EquationsThe Attempt at a Solution Tried to fixate...
12. ### What is the purpose of a rotary encoder?

I apologize in advance if my post is in the wrong section. I'm writing a program to control a stepper motor. The motor came with a motion controller and an encoder. I'm not sure how the encoder should be used. I can program the controller to set the "zero/reference" point and tell the stepper...
13. ### Circuit Model for a Rotary Contact?

Hi Everybody, First post on the forum, this one's stumped me I'm afraid. I'm basically trying to model a rotary connection in an AC circuit, and I'm having a bit of trouble with it. Ideally I'd like a reasonable approximation with conventional circuit elements. Basically I've got a...
14. ### Rotary or centrifugal jet spinning (nanofiber)

Hi, I am a research student, working on rotary jet spinning. while spinning, nanofibers are formed but it's not attached properly to the collector. It became like a spider web. You guys have any idea why it became like that?
15. ### How would rotary motion be converted to linear in robot?

How would the rotary motion of a robot / exoskeleton arm be converted into linear motion so that the arm can move objects and lift weights in a conventional manner, such as when people are weight lifting in a gym?
16. ### Rotary Mechanical Brake System

Hi, I am looking into a braking system which can limit the rotational speed of a platform; the assembly consists of a fixed vertical shaft and a rotating outer tube (seated with bearings). The platform diameter is >5 times larger than the tube. I have looked into the typical band brake...
17. ### Debouncing rotary encoder circuits

Hi, In this Raspberry Pipboy Project, Niel Corbett attempted to recreate the pip boy as a real life functional device, and in this project he is using two rotary encoders. Here' the link to the code for his project...
18. ### Help finding a rotary encoder with interupt capabilities

In this project, https://bitbucket.org/selectnone/raspipboy/src/73553033cfbc7c0a88f10332b8d09aa259a6b375/arduino/pipboyControls/pipboyControls.ino?at=master&fileviewer=file-view-default 14 // Change these pin numbers to the pins connected to your encoder. 15 // Best Performance: both pins have...
19. ### Forces opposing rotary motion other than Inertia

Hello Gurus, What are the forces opposing rotary motion? And how to calculate them? For eg., if we have a shaft rotating about it's own axis, are there any other forces that oppose this motion other than bearing friction, like air resistance or some other forces. And how to calculate these...
20. ### Railroad wheels and energy generation

How much energy generation potential would one rolling wheel on a train produce if it was hooked up to a generator if the train is rolling with continual momentum at various speeds. What is the reasonable optimum velocity of the train to maximize energy generation? How would you figure this...
21. ### Rotary to linear motion using a crank

Hello guys, since linear motors are too expensive I decided to buy a rotational motor and use some gears and a crank mechanism to get enough torque and translate rotation into linear motion. I need to meet a certain force on the shaft though. The question is how do I calculate the resulting...
22. ### Pivot Failure on Rotary Actuator

I have simplified the problem down to something like a physics textbook question, although this is a practical problem where the pivot on my rotary actuator has been damaged by a faulty driver which caused the armature to ram into the endstop. Obviously this needs better protection. My problem...
23. ### Rotary evaporator contamination

Homework Statement Before, I started to evaporate my solvent (butanol) by using rotary evaporator, I greased the ground glass joint holding my flask and bump trapper. Subsequently, I secured my flask sample and the trapper with Keck clip . Is there any possibility that my sample may have been...
24. ### Need to compress air given rotary motion input

Hey all. I'm looking to convert rotary motion into compressed air. I'm seeing there are hydraulic gear pumps I can buy, although I'm not sure I can use them with air. Any advice? Thanks
25. ### Incremental rotary encoder motor help

Homework Statement Hi please see the image that I have attached. The text colored in red is the data I need to calculate. Homework EquationsThe Attempt at a Solution The encoder has 128 counts per revolution So to calculate corresponding angle change this I what I did I divided encoder count...
26. ### How to Design the Complex Shapes of a Rotary Engine

Allo, this is my first post here. I must say this forum has everything not just Physics but Mathematics and Engineering, all my favorite things. Introduction: I would like to start with an introduction of a 'rotary engine' for those who don't know. Unlike the common boxer piston engine with...
27. ### Modeling mathematically a rotary flexible beam

Hi, I am trying to mathematically model the rotation of a rotary flexible beam. There are numerous papers which study this topic but all of them are considering the beam as a fixed-free one. My case is different. This is the beam I am trying to model. The motor axis is at the square portion...
28. ### Trying to understand rotary phase converter output....

I am looking to build my own rotary phase converter for utilizing 3ph devices however I am having a difficult time wrapping my head around the aspect of producing 120* out of 180* power. PracticalMachinist forums have a plethora of threads on this topic but after reading many of them I find...
29. ### Rotary to vertical motion (Designing a vibrating platform)

Hi, I am designing a vibrating platform that will move strictly up and down (total displacement of 1 inch). The load on the platform will vary between 0 and 160kg. The mechanical assembly/mechanism (which is underneath the platform) is motor>belt>flywheel>crank attached to a 1 inch shaft long...
30. ### Does Conrod Length Affect Torque in Engines?

Hi, Sorry if this is in the wrong thread I'm new to the forums. I was recently talking my mate about how engines produce power and torque and how there's so many factors in it. I mentioned the length of conrod would be a factor but my mate disagreed that it has no effect on torque. To my...
31. ### Rotary system stiffness/travel question

http://i.imgur.com/UNrCRD0.png How can I calculate k1,travel2 & k2,travel2 in this system? I know that k_series = k1*k2/(k1+k2) but that is the extend of my knowledge.
32. ### Rotary Screw Engines for ORC Systems | Jordan

I've been reading a lot about rotary screw compressors and using them as expanders in ORC systems. There are about 3-4 companies making these for ORC systems and they seem to be very reliable and efficient. They are much more tough than turbines; they can take dry steam ,wet steam, saturated...
33. ### Rotary Transformer: Transferring Current & Power?

If I have a rotary transformer in order to transfer some current o or from a rotating part, I wonder doesn't it add some extra power induced from the rotational motion to the secondary side of the transformer , since atleast one part of it is rotating with respect to other.? Like for example I...
34. ### Help -- Linear to rotary motion, cw and ccw direction

Hello,im doing a home project. I have an idea to make a venchile which will move back and forward as well as turn. Its something that i will be able to control with control device,if i press forward it goes forward etc. The thing is that i want to make it with linear...
35. ### Struggling to find a way to measure rotary torque

Homework Statement I have been struggling, for over a month now, to find a way to measure instantaneous torque from a servo motor. Here's a servo that look similar to the one I'm using: https://www.servocity.com/html/spg805a-bm_standard_rotation.html I need to find a way to measure the torque...
36. ### RPM Effects on CFM & Pressure of a Rotary (Roots) Blower

Hi, I would like to know how the RPM of a root blower will affect the CFM and pressure created by the blower. The confusion that I have is this: Generally when RPM is decreased, both the CFM and pressure decreases. But according to Bernoulli's principle, should not one decrease and the other...
37. ### How to design a radiator to dissipate heat generated by a 39 KW rotary engine?

No separate coolant is used, instead lubricating oil to be used for both lubrication and cooling of engine. How to calculate radiator size, coolant flow rate?
38. ### Where Can I Find a 7-Position Rotating Cylinder Switch for My Prototype Device?

I'm working on a prototype device, and I'm currently figuring out the form factor. On the turn indicator of my car, there is a ring with several positions that will control the lights. I'm thinking that something similar would work well on the handle of my device, and I'm looking to purchase...
39. ### Need a solution -- converting a translatory motion into rotary

Can anyone suggest me a mechanism which can provide me a good rpm when I'm converting a translatory motion into rotary one. I've crankshaft in ma mind. The load is of about 250 kgs and its loaded on a panel and I need to convert that linear downward motion into rotary and with a good rpm. And...
40. ### Alignment of a Rotary Kiln Neck

Hi, i´d like to ask support to solve the following problem: One of my customers has an horizontal rotary kiln, equipped with riding rings and carryings rollers. Due to some overheating of the kiln shell, nowadays the whole kiln and the kiln neck is wobbling about 70 mm (+-35 mm) around the...

Hello Everyone, First time posting on this forum and looking forward to see what you guys can teach me! I am working on a program for a Raspberry Pi as a controller for a mechanical rotary and need some help from you physics enthusiast out there. Looking for some insight on the calculations...
42. ### Rotary (Gears) question - angular acc/velocity involved

Rotary (Gears) question -- angular acc/velocity involved Homework Statement Homework Equations w (angular velocity) = alpha (angular acceleration) t w1 / w2 = r2 / r1 |a| = sqrt( (a(tangential))^2 + (a(normal))^2 ) The Attempt at a Solution Since A has a constant angular...
43. ### Factor of safety for rotary blades

anybody here who knows the factor of safety for rotating blades? ASAP. thanks!
44. ### Meaning of specifications for SDS rotary hammers?

Online, I see SDS-plus chuck rotary hammers with specifications like "Makita 1 inch D-Handle SDS-PLUS". What does the "1 inch" specify? I think the shanks of all SDS-plus bits have the same dimensions. So does the "1 inch" refer to the largest diameter bit that is recommended for use...
45. ### Finding a Suitable Rotary Actuator for Wheelchair Ramp

Can someone please help in finding a suitable rotary actuator? I need it to lower the rear wheelchair ramp of a car. So the motor would attach directly to a shaft. When it causes the shaft to rotate it would lower the ramp which is welded onto the shaft. I'm finding it hard to find a rotary...
46. ### Misc. Home project - rotary table calculations

Hi guys, I'm a mechanical engineering student and my dad want's a simplified motorized rotating table. I want to take it as a chance to implement my study in it, and I'm doing it all the way modeled on solidworks and animated. The calculation part is holding me back, there's a couple of things...
47. ### How can I detect rotary motion in CNC machines using a standard method?

Hello everybody, I am basically in computer & electronics field. In one of my project, I want to get the status of the motor of cnc machines (to detect whether it is running or not). Speed is not important. Presently I am using proximity sensor near the motor shaft. I get pulses when motor is...
48. ### Rotary atkinson cycle engine

http://white-smoke.wetpaint.com/page/Rotary+Engine does anyone know of this engine being used in production?
49. ### Understanding Rotary Oil Pumps: Filling, Ballast, & Oil Pressure

Hi everybody. I'm studying this kind of pumps right now but I'm finding a few difficulties trying to understand how it works... First of all i know it needs to be filled with oil, right?but totally or partially filled? When we start the pump the rotor starts spinning so it starts to evacuate...
50. ### Converting unidirectional linear motion into rotary motion?

Does there exist a device to convert a unidirectional linear motion into a rotational motion? I have only been able to find devices which do the exact opposite. I am probably missing out on some kind of key point here but I don't have much of a background in physics so please don't slam me too...