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  1. S

    Calculating bearing life

    I am a little confused on how to calculate the bearing rating and life for a gearbox in a mixer application. The only information that they are providing is the following, using a 1/4HP motor, 0.08 HP expected loading, a max torque of 87.2 in-lbs, 175.8 in-lbs bending max, and 632 psi expected...
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    Torque for Rack and Pinion

    I need some help calculating a rough approximation for the amount of torque needed to lift a 3600lb platen. We are planning on using a motor and worm gearbox to drive 4 pinions to lift the platen. I'm looking to move this platen 48 inches in 6 seconds. The pinion is 4" diameter. Am I...
  3. S

    How to calculate power using amps drawn?

    Is there a formula that I can use to calculate the HP a motor is actually making if all I have is amp draw? I am trying to size a gearbox, but the customer has no idea what torque is needed. All they know is the motor is drawing 5 amps when it spikes and 3.5 amps when it is running. I am...
  4. S

    Servo motor for a gearbox

    I am running into a minor snag and would like to know if I am going in the right direction or not. Most gearbox catalogs rate everything for input HP rather than input torque. Would I be able to calculate the motor HP by rearranging the Torque(in-lb) = HP*63025 / rpm, or in this case...
  5. S

    Gearing Backlash Arcsine to Arc minutes

    Thank you Tom G and Baluncore.
  6. S

    Gearing Backlash Arcsine to Arc minutes

    Working on a project at work for backlash in a gearbox. I need to know the amount of backlash in arc minutes that this particular ratio has. Wondering if my approach is on the right path. So can calculate the loose tolerance by the amount of end play in the input shaft and output shaft, add...
  7. S

    Gearbox sizing

    Baluncore, as always thanks for your help.
  8. S

    Gearbox sizing

    If I have a 7.5HP motor running at 1750rpm with a pulley and v-belt and connect it to a gearbox, where the right angle worm gearbox sees an input speed of 580rpm, how would I go about sizing the gearbox? Am I correct to say that I would size the gearbox for the lower input speed and more...
  9. S

    Converting to Arc minutes

    Thanks everyone for the replies. Greatly appreciated.
  10. S

    Converting to Arc minutes

    How can l convert an inch dimension to arc minutes? We have a customer who requires a 3 foot diameter roll not move more than an 1/8 inch. I need to convert the 1/8 inch to arc minutes to compare to the backlash in our gearing. Any help is greatly appreciated.
  11. S

    Calculating the Torque to mix a liquid

    There is a tank that is 12' 2" long and 65" in diameter that is capable of holding 2000 gallons of liquid asphalt, which is calculated to be 8lbs per gallon, viscosity is 8000CP. There are 8 paddles in this tank that they want to rotate around 25rpm. The diameter of the paddle arms is 60"...
  12. S

    Static and Dynamic torque of a gearbox

    A customer of ours called and is asking for the static and dynamic torque of a right angle worm gearbox, how would I calculate this? Secondly why would this need to be known? Thank you to all of those who reply. SevenToFive
  13. S

    Torque to move a loaded cart

    JR, I would like to do the simple way of just measuring rather than doing all of the calculations but this unit isn't even built yet and where it is being built is 2500 miles away from me. Looking through my past work, I think my calculated torque value is way way to high. I am going have to...
  14. S

    Torque to move a loaded cart

    I would like to see if I am on the correct path here and didn't miss anything for a project at work. If I am trying to move a cart that weighs 10 tons, this includes the weight of the cart and its load, the wheels of the cart are 10 inches in diameter, and with a 40:1 ratio gearbox I need to...
  15. S

    Motors and VFD's

    How does one calculate the amount of HP a motor makes when it is not running at a full 60Hz? The reason for my asking is a customer wants to use a 1/4HP motor and a gearbox to vary the speed of a conveyor. At a full 60Hz we are figuring 1750rpm for the motor, and through the 7:1 gearbox the...
  16. S

    Ability to backdrive a gear reducer

    That is correct Nidum. I agree 256Bits, you would think they would have some better control on motor, like a potentiometer or something. And you're correct it will have to go forward and reverse, since the track it rides on is a straight line a couple hundred feet long.
  17. S

    Ability to backdrive a gear reducer

    Well hopefully this will help. We are rebuilding this trolley as they call it that rides on a level structure that has a number of doors or gates as they call them. Currently they manually push the trolley over to the desired door, connect a cable to the gearbox in the center and raise the...
  18. S

    Ability to backdrive a gear reducer

    Dr.D and CWatters, thanks for the input. The gearing company that makes the gearbox has told me that the lower ratio units such as this one is capable of being backdriven, the only way to stop backdriving is by installing a brake. However in this case our customer would want to be able to...
  19. S

    Ability to backdrive a gear reducer

    How can I determine if a single worm gear reducer will backdrive? The gearbox has a 15:1 ratio which has around 90 percent efficiency. The gearboxes output shaft also turns a pair of sprockets that creates a 3:1 ratio. This in turns 8" inch diameter steel wheel on a 28000lb trolley, that rides...
  20. S

    Moment of inertia of a gearbox

    Thanks Dr.D. It was a rather lengthy exercise in math, another engineer at work suggested making 3D models of the parts and letting Solidworks determine the moment of Inertia. Thanks everyone for the input.
  21. S

    Moment of inertia of a gearbox

    I just want to check to see if I am on the right path, I have to calculate the moment of inertia of a gearbox for an application. I was thinking of breaking down the input shaft/worm into different size cylinders since the shaft has different diameters for the the input and bearings. And then...
  22. S

    Torque for rotating table

    Is there a way to figure out the torque needed to rotate a work table without knowing the center of gravity? I have a customer who wants to use a 40:1 ratio gearbox to rotate a work station, the gearbox would have an 11" wheel on the input shaft for the operator to turn. However the...
  23. S

    Conveyor speed

    I was using 1750 rpm for a motor speed. Thanks again for the help.
  24. S

    Conveyor speed

    I am not really buying my calculations of a gearboxes rpm for some conveyor applications. First conveyor has to travel 30 feet in 4.5 minutes with 2" rollers. If I divide 30' by 4.5minutes I get 6.667feet/minute and with a 2" diameter the gearbox should be about a 12:1 ratio. The other is a...
  25. S

    How to calculate maximum gearbox input torque

    I am a bit confused by a customer and their request to know what the maximum torque he can apply to a gearbox when the motor input speed is 258rpm. The motor is a 2HP brakemotor, 1750rpm at 60Hz, 460VAC 3phase, 1.65 amps motor tested. The gearbox has a 200:1 ratio rated for 0.093HP with an...
  26. S

    Torque for an auger

    Haruspex, thanks for reconfirming that I am missing something to complete the calculations. Asymptotic, Thanks for the links.
  27. S

    Torque for an auger

    I am trying to figure out the torque needed for an auger, but I seem to run into a wall. The auger is 6.00 inches in diameter and 44 feet long and on a 17% incline. The weight of the product going through the auger is 29lbs per cubic foot. So I calculated the cubic feet of the auger, 3.14 *...
  28. S

    Meaning of Static Shock Load?

    A customer of my employer emailed me with some requirements for a new machine that they plan to build. Everything was fine until I got to the part of the static shock load requirement of 2700in-lbs. A static load is a force/load put on for a long period of time, but shock load is a sudden or...
  29. S

    Calculating torque

    Hopefully this drawing will help clear things up. Thanks to everyone who replies.
  30. S

    Calculating torque

    The red section rotates around the circle which runs through the fixture where the intersection of the red section running left and right and the red portion running up and down.
  31. S

    Calculating torque

    The red section of this fixture rotates 90 degrees it weighs 3600lbs, and is 130 inches wide. It is made out of 10 inch steel channel. On the left of the drawing is the dimension of 40" and the pivot point is actually in the center. We can rotate it by hand if you grab onto the end that is...
  32. S

    Torque to roll up mats

    There has to be some sort of torque to turn the reel that will pull the mats up. Even if we roll up the 150ft in 5 minutes there has to be a torque generated...right? But how do I calculate that?
  33. S

    Torque to roll up mats

    I volunteer with an athletics group that has some large mats that they roll out for practice and I started thinking of a way for us old timers to roll them up at the end of practice. The mats are rolled up on a reel, that when empty is 14" in diameter, when full with the mats the diameter is...
  34. S

    Sizing 3 gearboxes

    I have a system that will require 3 different gearboxes. Starting on the right we have a roll of felt that is 36 inches in diameter and weighs 4000lbs. The felt is going to be fed into the table in the middle off of roll number 1 on the right by gearbox number 2. Once the felt is cut, gearbox...
  35. S

    Torque to rotate a drum

    I would have 1500lbs, 0.50 for bearing efficiency, and 48" from the center of the drum to the outside, which would give me 36000lb-in, which seems a bit on the high side.
  36. S

    Ball Screws and torque

    Thank you for the link.
  37. S

    Torque to rotate a drum

    We have a 1500lb steel drum that has a 8 foot diameter that we need to rotate to wrap up air filter material. The drum is supported by bearings on both sides and needs to turn at 0.02rpm. I calculated the torque, using T=Moment of Inertia * Angular Acceleration. For the moment of inertia I...
  38. S

    Ball Screws and torque

    I have a set of 4 ball screws, 2 inch diameter by 0.50", one in each corner to lift up a 12,000lb transformer. Each side will have one motor driving a right angle worm gearbox in the center that will power the two other right angle gearboxes that turn the ball screws. I was given that the...
  39. S

    Conveyor Torque

    Well the customer called, it seems that many of the original things have changed. Now the castings will be sliding onto this conveyor that will be 4 feet wide and 10 feet long and level with a 14 inch roller. Can my same calculation as above used to determine the torque requirement? Thanks to...
  40. S

    Conveyor Torque

    MU was a coefficient of friction. Thanks for the help.
  41. S

    Conveyor Torque

    A company called the other day with a question about their conveyor. My company did not build the conveyor but did supply the gearbox. The conveyor is 8 feet long, and 4 feet wide, it is level and transports castings to the grinding department of a foundry. The motor they are using is a 4 pole...
  42. S

    RPM to MPH

    I need to figure out a gearbox ratio to get a 12 inch wheel to travel at 2mph. If I remember right the equation should be 1foot * 3.14*gearbox output rpm*60 then all divided by 5280 to get the final mph. Am I on the right path? Then I need a gearbox output around 58rpm. Thanks to all of...
  43. S

    Calculating Starting Torque

    Baluncore: Thanks for all of your help with this so far. JBA thanks you as well. The output shaft of the motor goes to a 7" center distance gearbox with a 50:1 ratio, so when the motor sees all 60Hz the gearbox input is around 1750rpm and the output is 35rpm and 13011 in-lbs of torque. The...
  44. S

    Calculating Starting Torque

    What time per revolution, or RPM, of the weldment is wanted ? For the desired rpm, we would be going from 0-3rpm in about a 2 seconds. Is the motor an induction motor designed for three phase 400VAC at 60 Hz ? Yes a 3 phase 60Hz motor with an output speed of 1800rpm. How many poles, or what...
  45. S

    Calculating Starting Torque

    So for the valve I can just break it up into 3 components and add them together for the Moment of Inertia? Then add the moment of inertia for the length of pipe to that and then if I remember right us the equation Torque = (Moment of Inertia*Difference in Speed) / (308 * Time to accelerate)...
  46. S

    Calculating Starting Torque

    Is there a quick and easy way to calculate the moment of inertia and come with with a conservative value for the starting torque needed to spin the piece of pipe and valve? The customer tells us that the valve weighs 12000lbs total and 6000lbs at top of the valve with is 78 inches from the...
  47. S

    Calculating Starting Torque

    I have been trying to figure out the starting torque needed to start rotating a pipe and valve in a weld fixture. The pipe is 304 stainless 24 inches outside diameter and has an inside diameter of 23.625 inches. The length of pipe varies but so far all of the lengths of pipe get a valve welded...
  48. S

    Overhung load, extending output shaft

    I have a hollow output shaft gearbox that will accept a 1-1/8" solid shaft, I want to extend the output shaft of a gearbox by 6 inches from the face of output seal to the end of the shaft. The manufacturer states that gear reducer is rated 899 lbs with the hollow shaft or a solid shaft that...
  49. S

    Pulleys, Torque, and inclines

    Thank you very much Jack Action for all of your time explaining this to me.
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