Challenge: Reduce gearbox inefficiency for conveyor systems
Solution: Electric Torque Machines’ direct drive motor
Company: Dorner Manufacturing
Headquarters: Hartland, Wisconsin
Operation: Conveyor manufacturing
Conveyors move both large and small objects at relatively slow speeds, sometimes with frequent starts and stops. Conveyor drives, the motorized systems that move conveyor belts, require high torque to meet the acceleration and load-carrying capacity requirements of each conveyor. However, conventional motors produce insufficient low-speed torque to enable direct drive for conveyors, so a gearbox is needed to match high motor speeds to slow conveyor speeds.
Dorner Conveyor found that gearboxes add cost and complexity to conveyor systems, including several additional moving parts and lubricant seals, all of which are prone to failure. For instance, the worm gears used in conveyors are relatively inexpensive and notoriously inefficient. In fact, as much as 80 percent of the energy in these motors can be lost as heat. As a leader in the industry, Dorner set out to find a better method.
Dorner found that Electric Torque Machines’ (ETM’s) advanced direct drive motor improved on these challenges posed by conventional motors. The direct drive technology originally was developed for electric vehicles and now has been adapted for use in conveyor systems. “We started work in 2007, looking at a broad variety of applications, and determined that our competitive advantages — direct drive with low cost, high efficiency, small size, low weight and high reliability — were a great fit for applications with less than 1,000 rotations per minute,” explains ETM Chief Technical Officer Thomas Janecek. “Then we realized that this same characteristic— eight or more times higher torque at low speeds — was a perfect match for conveyors and other material-handling equipment.”
ETM’s technology incorporates as many as 10 times more electromagnetic poles, which are used to drive the rotary motion, than conventional motors of the same size. This enables the direct drive motor to produce a high level of torque at low speeds. As a result, the motor quickly and smoothly transitions conveyors from a stationary position to full operating speed.
In addition, ETM’s direct drive motor moves Dorner’s conveyor belts at speeds of 10 to 500 rotations per minute without any gearing, which gives Dorner the opportunity to reduce the number of motor and gear combinations, decrease the driev system size and weight, and improve the energy efficiency of the drive system.
This collaboration between Dorner and ETM resulted in the launch of Dorner’s Universal Drive in 2016. The new system enables conveyor drives that are less expensive with double the speed range and 60 percent higher energy efficiency compared with conventional AC gear motors. Dorner also reduced its drive system types from 42 different motor and gear combinations to a single ETM direct drive motor because the wide speed range and superior load-carrying capacity of the motor covers all speeds, loads and mounting positions.
“ETM technology has simplified our conveyor drive package offering, cut our stock-keeping-unit (SKU) count almost in half and cut our costs considerably,” says James Lubow, Dorner’s packaging conveyance product manager. “The simplified design and SKU reduction is beneficial for our customers as they are stocking fewer service parts and can use this universally across our largest conveyor line. With many customers running their plants 24/7, we expect them to benefit greatly from this reliable system.”
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