Trolleys are used with electric hoists and enable the hoists to move on a track. Trolleys can be distinguished by the following attributes:
- Load capacity: Measured in pounds force or tons.
- Beam height and width: The height and width of the beam to which the hoist will be affixed.
Items to consider when selecting a hoist:
- Weight of load
- Power supply
- Speed of lifts
- Lifting height
- Frequency of lifts
- Duty cycle
The powered hoist industry uses a service classification system to help you select the proper hoist. See the chart below for details.
Electric Hoist Service Classifications
SERVICE CLASSIFICATION | TOTAL EQUIPMENT RUNNING TIME | MAX. START/STOPS PER HOUR |
TYPICAL AREAS OF APPLICATION | |||
H4![]() |
Approaching 50% of the work period | 300 | High-volume handling in steel warehousing, machine shops, fabricating plants, mills and foundries. Manual or automatic cycling operations in heat-treating and plating operations. | |||
H3 | Not to exceed 25% of the work period | 150 | General machine shop, fabricating, assembly, storage and warehousing use, where loads and operation are randomly distributed. | |||
H2 | Not to exceed 15% of the work period | 75 | Light machine shop, fabricating industries, and service and maintenance work, where loads and use are randomly distributed with capacity loads infrequently handled. |
How to Choose What Service Classification You Need
![]() Determine the maximum weight you need to lift. (Include lifting, supporting and positioning devices.) Ex: 2400 lbs. (includes pallet, drum, sling, etc.) |
![]() What is the nominal voltage (±10% of rated voltage) in your facility? (Single-phase 115 or 230V; 3-phase 208, 230 or 460V) Ex: 230V |
![]() What speed do you want to lift the load? Industry standard for 1/8 to 1 ton is 16 ft./min. (fpm); 2 tons is 8 fpm. For flexibility, consider a variable speed lift. Ex: 8 fpm |
![]() Measure from the point of mount to the floor. Ex: 12 ft. |
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![]() What is the actual distance the load must be lifted and lowered? Ex: 7 ft. |
![]() Determine the number of lifts per hour for the job. Ex: 15 |
![]() How many times does an operator activate the push-button control? Rule of thumb: 8 start/stops per cycle (load lift and lower). Ex: 120 start/stops |
![]() Hoists have a Service Classification rating. To determine the classification for your job, see the calculations below: Ex: 12 ft. |
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Once a % On Time is determined, see the Electric Hoist Service Classifications to determine the hoist needed. Selected hoist in this example should offer 2-ton capacity, 230V, 3-phase operation, 15-ft. lift, 8 fpm and have a 44% or H4 service classification. Example is based on having nominal voltage and 80°F ambient still air. Higher temperatures and/or voltages outside of nominal range will result in reduced duty cycles. |