Factors to Consider When Selecting a Hoist

Hoisting & Lifting Equipment | How To's | By | Feb 17, 2020

Purchasing or specifying hoists to lift heavy objects in close proximity to equipment and/or personnel is a decision that deserves thoughtful consideration. In this article, we will identify some important items to factor into your decision-making process.

Download a complete guide to selecting the right hoist for your application.

Determining Required Capacity

When selecting a manual hand chain hoist, the rated capacity should be at least as high as the weight of the heaviest load to be lifted and no higher than the rated capacity of the pad eye, monorail system or other overhead structure from which the hoist will be suspended.

In addition to the factors listed above for manual hoists, when determining the capacity requirement for an electric or pneumatic hoist we must not only consider the weight of the heaviest load to be lifted, but we must also determine the Mean Effective Load ( MEL) and apply the MEL factor of .65.

For more detail refer to ASME HST-1, Performance Standard for Electric Chain HoistElectric Chain Hoists, Section 1-1.1 through Section 1-2.4.2

Selecting a Suspension Type

Chain hoists can be suspended in a fixed location or they can be trolley mounted by means of a top hook or mounting lug. Trolleys can be rigid or articulating. Trolley traverse can be plain (push type), hand geared or motor-driven. See below for examples of typical chain hoist suspension types.

Choosing Lift, Reach & Headroom

It’s appropriate to group these three parameters together because they are closely related. Simply put, the length of lift is the distance the load hook can travel between its fully lowered and fully raised positions.

Reach is equal to the difference in elevation between the hoist suspension point (pad eye or trolley beam running surface) and the hook saddle in its lowest position.

Headroom is the distance from the hoist suspension point and the fully raised hook saddle. For a hoist with top-hook suspension, the headroom dimension is the distance between the saddle of the top hook and the saddle of the fully raised lower hook.

Understanding the Operation Type Needed for Your Application

Operation type refers to the power source used to drive the hoisting motion. Operation types include manual, electric or pneumatic (air) power. Some of the criteria for determining which of these types are best for a given application include initial cost, availability of utilities, duty cycle, lifting speed requirement, operating environment and more. 

Manual hand chain hoists have the lowest purchase price, making them ideal for applications involving temporary or infrequent use, low capacities, short lift height and when power sources are not available.

Electric and pneumatic hoists offer faster lifting speeds, are more ergonomic and are better suited than manual hoists for heavy-duty cycles, high capacities and long lifts.

Air hoists require a substantial volume of compressed air for operation and are often used for applications involving long lifts or high duty cycles and in areas where electric power is impractical or unavailable. Air motors tend to be self-cooling, providing nearly unlimited run time capability. And, because there is no risk of electrical arcing, air hoists are also used in some hazardous areas where flammable gases or dust may be present. One downside is that air hoists tend to be significantly louder to operate than electric or manual hoists.     

Electric hoists can have a lower purchase price than pneumatic hoists. They do not require the purchase and installation of an air compressor and are normally quieter than air hoists to operate. If suitable electric power is available, electric hoists are selected more often than pneumatic for most general lifting applications. Electric hoists can also be equipped with special motors and controls to make them suitable for use in designated hazardous areas.

Determining Required Duty Class

The American Society of Engineers (ASME) and The Hoist Manufacturer’s Institute (HMI) have developed and published standards for hoists, including hoist duty ratings. These duty classifications are based on numerous factors, including the number of lifts performed per hour over a given work period, the average and maximum load that is lifted, the frequency at which the maximum load is lifted, the average distance the load is raised and lowered, and the maximum number of stops and starts per hour. The table shown below is provided for reference to help you understand the significance of duty class ratings provided by the hoist manufacturer for their products.

Picking Your Lifting Speed

Hoist lifting speeds vary widely and should be considered carefully before making a selection. Generally speaking, faster lifting speeds are preferred for long lifts or for shorter lift applications in which a high number of lifting/lowering cycles must be completed in a relatively short period of time.

The weight of the load to be lifted, along with the required lifting speed and hoist gear ratio, determines the torque requirement, which in turn dictates the motor horsepower required to provide that torque.  Higher horsepower motors can add to the size, weight and power consumption of a hoist, as well as its cost.       

The most common lifting speeds are between 8 and 32 FPM. CMCO offers powered hoists with speeds as low as 3 FPM and as high as 64 FPM.

Determining a Power Supply

Some electric hoists are designed to operate on either 120 or 230vac, single-phase power. These hoists are typically ¼ to 2-ton capacity and are most often used in home workshops, garages, and some light manufacturing facilities. Most industrial facilities throughout North America are wired for 208,  230, 460 or 575v, 3-phase, 60 Hz power. The most common are voltages are 240v and 480v, although 575v is also frequently used in Canada. It is important to verify your available power supply before attempting to purchase or specify an electric hoist.  

Selecting a Control Type for Your Electric Hoist

To reduce the risk of serious injury due to electric shock, most electric hoist controls do not run on the full line voltage that is supplied to the hoist motors. Instead, they utilize transformers to step down the control voltage to 120v or 24v. The majority of hoists in the U.S. feature 120v controls.

Hoists can be equipped with a variety of different control types. The most common are single-speed or two-speed contactor controls. Two-speed contactor control also requires a special motor with two-speed windings.

Another available control type is the variable speed drive (VFD), sometimes also referred to as an adjustable frequency drive (AFD). This solid-state control system adjusts AC motor speed and torque by varying motor input frequency and voltage. For example, a variable speed hoist that runs at 20 FPM on 60 Hz power would operate at roughly 10 FPM if through a VFD control the frequency is reduced to 30 Hz.      

Closed-loop variable frequency drive systems, also known as flux vector drives, take VFD control to another level, using an encoder on rotating components, such as hoist motor shaft or gearbox output shaft, to send feedback to the control module. This type of closed-loop control system can provide extremely accurate speed control and load spotting and can be used in conjunction with a programmable logic control (PLC) to automate the lifting and lowering functions based on preset parameters.  Another significant advantage of a flux vector hoist drive is dynamic braking, which provides softer stops and can significantly extend the life of the motor brake.

Choosing a Control Pendant

The majority of electric chain hoists come equipped with a hard-wired control pendant that is suspended from the hoist, trolley or crane (where applicable). In some cases, hard-wired pendant stations may also be wall-mounted. Wireless radio remote control systems are also available and can allow the operator to control hoist functions from anywhere within the general vicinity of the hoist. Radio control pendants can also be smaller, lighter weight and more ergonomic than a hard-wired pendant.

Download a complete guide to selecting the right hoist for your application.

Understanding Dimensional Constraints

Before selecting a hoist, it is important to consider any dimensional constraints that exist in the area where the hoist may be used. Issues such as headroom clearance, side clearance along the length of monorail or crane beam, and end approach are particularly critical clearances.

The term “end approach” (see dimension “A” to the right) can be defined as the distance between the centerline of the lifting hook and the end of a monorail beam, bridge beam or runway on which the hoist is operating.

This is important as it relates to the ability to center the hoist over the load to be lifted to avoid side pulling. Learn more about the dangers of side pulling.

Determining Needs for Special Environments

Standard chain hoists are designed for “normal operating conditions.” Conditions such as temperature extremes, unprotected outdoor areas, salt-laden marine environments, corrosive atmospheres, classified hazardous areas, clean rooms, and wash-down areas, among others, may require hoists with special modifications or optional features that are designed for those locations.   

We hope the information in this article provided insight into some of the considerations that should be taken before buying or specifying a hoist. Selecting the right hoist for the application can be the first step towards safe, efficient and ergonomic movement of materials. For further assistance with your overhead lifting requirements, please contact our application experts.

A BUYER'S GUIDE TO ELECTRIC CHAIN HOISTS

Why should you use an electric chain hoist?

• Electricity is almost universally available and inexpensive.
• Productivity, ergonomics, and safety are enhanced.
• They are normally smaller and more compact than wire rope hoists, as a drum is not required to store wire rope.
• Overload clutch to prevent dangerous overloads is normally standard.
• Portability is excellent as standard hook mounting allows simplified installation (Lug mount required on wire rope hoist to wrap rope on drum precisely).
• Lift can be changed at any time with minimal cost by simply changing chain length.
• Numerous configurations and speeds are available in lighter capacities.
• Chain tends to be a more durable lifting medium than wire rope.
• Headroom of chain hoists is often better.
• Chain hoists are normally less expensive than wire rope.
• Most chain hoist duty cycles are equal to wire rope.

When should you use an electric chain hoist?

• Any time your capacity is 3 tons or less apply a chain hoist unless some other circumstance specifically dictates wire rope.
• Any time your application is in a critical area, and the portability of a spare chain hoist allows easy replacement of another unit in need of repair.
• Any time you need true vertical lift and the lowest cost.
• Any time initial cost and total operating cost are important.

Which electric chain hoist should you use?

• Use one with a rated capacity no greater than the structure on which it will be placed.
• Use one in all medium to heavy duty applications with a capacity rating that is no less than the maximum load to be lifted and approximately 155% of the mean load to be lifted. Increase this percent as the duty cycle increases.
• Use one with the highest speed available that will not cause safety or spotting problems.
• Use a two speed model when precise spotting and higher speeds are required.
• Use one with a hook mount unless the inch or so gained with lug mounting is important, or you are going to use a motor driven trolley.
• Use one with a rigid hook mount to keep hoist aligned.
• Use one with a motor driven trolley above 2 ton capacity.
• Use one with a mechanical load brake when redundant safety is required to keep the load suspended.
• Use one without a mechanical load brake to prevent heat buildup in the gear case particularly on long lift applications.
• Use one with grease in the gear case when the immediate area must be completely free from possible oil contamination.
• Use one with good reparability and with which your maintenance staff is familiar
• Use a 3 phase model instead of single phase when 3 phase current is available because these hoists normally have a better duty cycle and are more dependable.

General Hoist Selection Tips

• The number of starts and stops per hour directly affects all electro-mechanical devices such as motors, contactors, brakes, and solenoids, by causing a buildup of heat due to the inrush amperage at startup being approximately 3 times the normal running amps. Operator training and proper equipment selection can minimize this frequent source of equipment damage. Two speed motors and inverters can solve many of the spotting problems that result in the improper, "staccato", use of the push button by the operator.
• When making hoist selection with regard to maximum capacity load to be lifted consider that ball bearing life for the equipment normally varies inversely according to the cube of the load. For example, a two ton hoist operated at a mean effective load of one ton will have a ball bearing life eight times that of the same hoist used steadily at its rated load. This can amount to huge savings in repairs and downtime for critical use hoists.
• Remember that manufacturer's warranties are against product and labor defects and not wear and tear. For all practical purposes almost any manufacturing defect will show up within a month or so of installation. The advantage of a warranty for "lifetime" as contrasted with 1 year is difficult to place a "price tag" on. Actually the most important factors regarding warranty claims are the reputation of the factory, and the distributor form which you buy a hoist. Ace has a 70 plus year history of standing behind products and customers to insure satisfaction.
• A limit switch on a hoist is one of the most important safety features available for electric chain hoists. These devices shut off the hoist when the hook rises to highest position and normally also when it reaches it's low point. There are generally two types of limit switches used in electric chain hoists shown in this web and there is one limit switch "substitute" that is not a limit switch at all. The two types of limit switch are the (1) screw type and the (2) paddle type. The "substitute" is a clutch in the gear case that slips when the hoist makes contact with the housing at the highest point. All limit switches are meant to be a safety cut off in case the hoist reaches the maximum travel. They are not meant to be used for a method of stopping the hoist a predetermined points. This is because the limit switch is a back-up safety mechanism. If the switch should fail in being used as a normal method of stopping, there would be no back up.
• A screw type limit switch operates normally by a screw and traveling nut mechanism that breaks a circuit in the control wiring and cuts the hoist off at the desired point. This type of limit switch is normally concealed within the hoist electrical cover and is set in accordance with the factory instruction.
• A paddle or actuator type limit switch is one that operates by the hook or some other actuator on the chain, contacting a paddle or other switch that opens a control circuit and stops the motion.
• The "substitute" is no limit switch at all but instead depends upon the use of a clutch mechanism in the hoist gearing to prevent damage when the hoist exceeds the maximum limit. Problem with this substitute is that when it operates, the clutch slips. If the operator holds his finger on the up button the clutch will continue to slip. Slipping of the clutch excessively will result in wear on the brake disc, and finally after an unknown time, with the inability of the hoist to raise the capacity load when required.
• Ace recommends hoists with either a screw type or paddle limit switch. Hoists with this feature are more costly.

CAUTION: These tips are provided as a starting point in the selection process and are not universally applicable.
Please consult our experts for the solution to your specific application problem.

Why should you buy a electric chain hoist from Ace Industries?

• Best selection of hoists from all major manufacturers insures that you will get the best hoist for your application
• Most complete inventory available insures that you get quick delivery of the hoist you need
• Most competitive price is guaranteed.
• Best technical and application advice to insure that your electric chain hoist purchase will meet your need
• Same day shipments
• No labor charges for changes to lifts and most other normal modifications
• Best after sale service. We are a warranty repair center and authorized master parts depot for all of the brands that we represent.
• Ace satisfaction guarantee*

*Ace satisfaction guarantee: If you are dissatisfied with any item purchased from Ace, that is a normal stock item for Ace, you may return it for full refund or credit at any time within 10 days following shipment. Items must be returned prepaid, and a return goods authorization number must be issued by Ace and be included with the return. Returned items must be complete, undamaged and in new condition. Stock items modified by Ace to fit a particular application such as changing chain lift, are not covered by this satisfaction guarantee and are subject to a reasonable restocking charge.