Guest Commentary: The Unconventional View May Lead To A Better Solution
24 VDC Motorized Roller System vs. the Traditional Motor-Reducer Conveyor System
by Larry Boroff – Director, Automation Systems Engineering
When confronted with distribution center capacity and efficiency problems, the traditional solution focuses on a typical conveyor system where 480 volts is delivered to widely distributed AC motors and transferred to a gearbox (drip pan included) that drives several long belts needing continual tracking. In many cases, and for many reasons, these mechanical Rube Goldberg monsters are the practical choice. But they are not necessarily the best choice. There are applications where motorized drive roller (MDR) conveyor systems utilizing low-voltage, 24-volt DC brushless motors may be the best, albeit unconventional, solution.
MDR systems are modular, offering nearly limitless “plug and play” flexibility. They can be engineered as complete systems (within their design parameters) or as sections within a traditional AC voltage system. This conveyor is built to accumulate. Not just on the straight runs like traditional conveyor but also on inclines, declines, curves, spirals, sorters and merges. Hate hearing or fixing air leaks? No air required. Reducer dripping oil on the floor? No oil or reducer required. Noise issues? This conveyor is not only quiet, but it only runs when there is product on it to convey. Proactive safety team? Take a look at the low torque of these motors and the reduced pinch points this technology offers. Limited maintenance time or budget?
Unlike a traditional conveyor that has several points of failure (belts, bearings, motors, reducers, pulleys, drive/snubber/take-up rollers, etc.), an MDR system typically has only four interchangeable parts that you need to troubleshoot. Space limitations? MDR systems are a good choice for smaller distribution centers or those transitioning from manual to automated operation. And their space-saving design and configuration are especially well-suited to replace old line-shaft conveyor in zone-routed pick modules for true zero-pressure accumulation service.
MDR systems do have their shortcomings. Sorter throughput is limited to about 32 cartons per minute using a 30° diverter and about 20 cartons-per-minute using a 90° diverter. And the initial equipment cost premium of 15 to 20 percent can be a barrier until a total life cycle cost analysis reveals the savings in power consumption (≥ 40 percent vs. AC powered systems), maintenance-friendly operation, minimum spare parts inventory, reliability and its wide flexibility for low-cost expansion or reconfiguration.
The point is this: when confronted with distribution center operating problems, it may be beneficial to seek out and evaluate unconventional solutions. The answer may not always be found in “the tried and true.” Stretch your thinking. Challenge your consultant to think beyond belts to track and bearings to grease. The rewards of satisfied customers and competitive advantage depend upon it … to say nothing of a more efficient and profitable operation for you and your organization.
Larry Boroff is Director, Automation Systems Engineering with MHI Member FORTE
