What is Hoist: Definition and 17 Discussions

In underground mining a hoist or winder is used to raise and lower conveyances within the mine shaft. Modern hoists are normally powered using electric motors, historically with direct current drives utilizing Ward Leonard control machines and later solid-state converters (thyristors), however modern large hoists use alternating current drives that are variable frequency controlled. There are three principal types of hoists used in mining applications:

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  1. G

    Electric chain hoist: need help with control circuitry

    I have been given an electrical chain hoist to repair. The symptom is that it suddenly stopped working. I have checked the motor's windings and they each show similar DC resistance of 0.0018 ohms. I have attached the schematic (dunno why it was rotated 90 degrees during the upload). The hoist...
  2. G

    Building Overhead Hoist: Is 5"x5"x1/4" Wall Sufficient?

    Hello, I am in the process of building an over head hoist in my shop.I've already taken delivery of the metal, so I hope I erred on the side of safety. I am spanning 20' and will be using a 1/2 ton electric hoist and trolly. I found a chart online from Harrington Crane Co. That specified that a...
  3. T

    Hills Hoist Mechanism: Understanding the Function and Assembly | Explained

    Firstly, am struggling to wrap my head around exactly how the mechanism for a traditional 'hills hoist' (as seen below) clothesline functions. The handle can be turned in order to raise the clotheslines but from my googling, the mechanism is different to what I was expecting. Would be...
  4. Crimpchimp

    Calculating the force acting on a pulley in a hoist system

    In the diagram below there is a hoisting system set up to lift a 1000 lb. unit up a radio tower. This unit is used for painting towers and is lifted using a capstan hoist. As the unit is lifted, it will be tagged with a 6ft. (adjustable) tag line with a pulley that travels up the end of the...
  5. T

    Torque required to maintain velocity

    Hi guys, I am designing (homework) a winch drum and am having a brain fart. i am trying to find the power required to maintain a constant velocity. i have figured out that the torque required to lift the mass is in 3 parts: 1. torque to accelerate the drum = 241 N.m 2. torque required to...
  6. V

    Servo vs ? for lift/winch/hoist

    Hello. As many others here, I am starting a project that involves some engineering and will at some point, if I go ahead with it, require an engineer to design and certify. But for now I'd like to understand the principals involved and dust off some of my 1st year physics and see how much of it...
  7. T

    HNC Dynamics help please -- Hoist cable looped over a winding drum

    Hi guys I am looking for help with some formulas, its for hnc mech eng, the question is as follows a winding drum with moment of inertia 24 kg m2 and a winding radius of 0.6m is used to accelerate a loaded hoist with mass of 850kg at a rate of 0.8ms by means of a cable, frictional resistance can...
  8. S

    Torque Help -- Tension in a Hoist Cable

    Hi, I'm having a problem with 3. (b) (ii) here. I know that the frictional torque is 1500Nm and that from (b)(i) being 5055N I assume this is multiplied by 1.5M (drum shaft radius) which gives me 7582.5N. Do I have to calculate the angular acceleration of the drum from here, which could then...
  9. M

    As Simple Hoist System Problem - Given Answer Wrong?

    Homework Statement A colliery lift cage can be considered as a simple hoist system. An investigation found that when raised from the bottom of the mineshaft, the cage accelerates uniformly for 10 seconds, travels for 70 seconds at constant speed of 3 m/s and just before reaching the pit head...
  10. S

    Pulley Hoist Free Body Diagram

    Hi All, I am an old dog, and rusty propeller head. I am having the most difficult time figuring out the forces on a pulley system I am working on. Can someone please review my sketch and tell me if I am even close. I would accept any suggestions and direction. Much Obliged -Steve
  11. G

    How Does a Chain Hoist Work Mathematically?

    Can anyone explain the mechanics of a chain hoist and its mechanical advantage, in mathematical terms,? thank you Bashyam
  12. M

    Designing a Patient Hoist Winch: Factors of Safety and Power Calculations

    Homework Statement I am trying to design and manufacture a patient moving hoist winch to move patients from wheelchairs to beds etc. The design have to has a safe working load of 180 kg and lifting speed 25mm/sec. I have to use factor of safety so here is my question. How can i find a...
  13. V

    Can a Pulley System Effectively Lift Patients Out of Bed?

    Hi there, I'm operating a hospital visitation program at the national hospital in Nairobi, Kenya. I'd like to make a pulley hoist for lifting patients out of bed. Any suggestions on a pulley system which would effectively suit that job? I'll be using metal pipes for the structure to attach...
  14. L

    F.B.D. for beam on disabled hoist (confirmation on work needed)

    Homework Statement Hi guys, I'm doing an assignment for college and designing a disabled hoist. I want to complete FBDs on the top beam especially. Can anyone help answer whether the work I've done is correct? Homework Equations the equations I used were the sum of all force = 0...
  15. C

    Have an any idea about hoist used in crane?

    i am working on a project of 450t eot crane project for final year. want detail on hoists and motor used for hoist. how i choose it?
  16. A

    Why Does My Single Phase Motor Hoist Fail to Lift Loads Consistently?

    I have used a single phase motor (220 V 50 hz) in a hoist application. It is used to lift a given load up & down, but being a single phase motor, it sometimes never lifts the load & starts to rotate in single direction only i.e never lifts the load. When you press UP button, it rotates...
  17. G

    Determine the acceleration of rope hoist

    Problem: To hoist himself into a tree a 72 Kg man ties one end of a nylon rope of negligible weight around his waist and throws the other end over a branch of the tree. He then pulls downward on the free end of the rope with a force of 358N. Neglect any friction between the rope and the...