Motorized Roller Conveyors: A Better Option for Small- and Medium-Sized Businesses

By Pat Knapke, Director of Engineering, Insight Automation, Inc.

 

Some businesses (particularly small- and mid-sized operations) whose logistics could use the benefits of roller conveyors—and zero pressure accumulation functionality in particular—may still be wary of purchasing such a system. Not necessarily because of the raw cost of the conveyor equipment but because of the lengthy time duration of implementation and associated cost, ongoing electric and compressed air utility usage, and skilled labor required for upkeep maintenance. Another key reason that maybe holds back such an investment is that today’s business patterns evolve at ever faster rates which make the conveyor system you need for today’s operations may not be the one you need for next year’s (or the next busy season’s) operations.

 

Motor Roller Conveyors vs. Gear Motor Conveyors

Now, there are newer technologies being utilized to help businesses combat these issues. Individual conveyor rollers that use their own internal motors have been around for years and are widely considered as viable motive power for conveying systems. Although a single motorized conveyor roller cannot physically perform the same work as one of its large multi-phase electric gear motor counterparts in a conventional design; with the right design concept, it doesn’t have to. Motorized Roller Conveyor sections are, generically-speaking, sections that utilize a single motorized conveyor roller that is only mechanically linked with enough free-turning (gravity type) rollers to constitute a controllable zone not much longer than the item to be conveyed. With the proper control system strategy, individual motorized roller conveyor zones can be easily assembled to make zero pressure accumulation conveyor subsystems, particularly for traditional carton-type handling applications.

 

The Modularity of Blocks ...

The right design concept is the key. Motorized roller conveyor sections with the proper control system strategy are inherently modular, both mechanically and electrically, thus creating a building block approach to system design. What this means is that instead of having a single 100-foot behemoth accumulation conveyor with its associated big honking 5 HP 480-volt gear motor and its own air feed drop; we now can have 10 or so manageable 10-foot modular accumulation sections that connect together. These modular sections require no air piping and their power sourcing can be as simple as plugging into a standard 120-volt household wall receptacle.

 

… With the Safety of No Pinch Points

As described above, our 100-foot behemoth’s 5 HP 480 volt motor can be a dangerous animal if a person was to get in the way of its drive train. A stray hand, limb, or piece of clothing can lead to tragic injury if one were to get placed in the wrong space or pinch point while this conveyor is running. Also, knowledgeable electricians and mechanics are required to service such a beast if there is trouble. The motorized roller unit in a typical motorized roller conveyor section is powered by 24 volts DC and is inherently safe because there are no major pinch points. Because a motorized roller only has to provide motive power and torque to a short zone; there is not enough drive power to be dangerous to people working around the conveyor. In most designs, a person can literally grab a running motorized roller with their bare hand and make it stop with only a handshake grip.

 

Shhhhh, Keep It Down

A really great thing about a motorized roller conveyor is that it is much quieter than a conventional conveyor. A conventional conveyor usually uses chains and sprockets somewhere in its drive train, which transfers vibration to conveyor frames, supports, and rollers, thus creating noise. To make matters worse, in our 100-foot behemoth conveyor example, the big honking motor and drive train run all of the time, so we have chain noise and vibration whether or not we are conveying or accumulating product. Motorized roller conveyor designs can typically achieve 60dB or fewer noise levels. Our latest motor roller designs achieve 45dB noise levels which are lower than most human conversations.

 

Green so You Keep More Green

Perhaps the greatest aspect of motorized roller conveyor operation is the fact that with the proper control system strategy, the motorized roller conveyor only runs when it needs to. In a typical accumulating system application, conventional conveyors run all the time whether they are accumulating product or not. In a typical motorized roller system, however, the rollers in a given section only run 10 percent to 50 percent of the operational time. This can equate to an energy savings of 30 percent to 70 percent compared to conventional conveyors that operate continuously. But that's not all. In recent years, designers have come out with motorized rollers with the speed (up to 969fpm) and starting torque (up to 215 in/lbs) of regular rollers that use even less electrical power. These low-energy motorized rollers can save an additional 20 percent to 30 percent of electrical power. All of this means a faster return on your investment.

 

Real Plug and Play

In recent years the term “plug and play” has become ubiquitous in our language to the point that it sometimes loses its meaning depending on the individual. Motorized roller conveyor truly brings the intended concept of plug and play to real form for conveyor system applications. With the proper control system strategy applied up front, a typical motorized roller conveyor section (say a 5-foot or 10-foot long unit) is electrically pre-wired at the manufacturer prior to shipment. A typical section will utilize plug connectors at each end to allow the unit to be set in place and simply plugged into the unit in front of it and behind it to make it operational. Why is this important? Well, the small- to medium-sized business we talked about before can easily add or remove sections as needed to alter or re-route their conveyor path (even temporarily) as needed to accommodate their business changes. Also, with the proper control system strategy applied, this endeavor need not require a gaggle of engineers, programmers, or technicians to accomplish. Often time the business' own people can make changes and modifications with minimal assistance from the original conveyor equipment or control system provider.

 

Spare Us the Maintenance Cost

We talked about the energy savings and the quiet operation of a motorized roller conveyor. The inherent advantages of motorized roller design bear fruit as time goes on in lower maintenance and spare parts cost. Simply by the virtue of running only as needed, a motorized roller conveyor has a longer base equipment life. Remember our conventional 100-foot behemoth conveyor and the noise it makes? Well where there is noise, there is typically wear. Most all maintenance and wear items associated with conventional conveyors are part of the drive train (sprockets, chains, belt lacing, etc.). Even the most modern and efficient gear motors require regular maintenance and lubrication. Today’s typical motorized roller unit uses sealed-for-life bearings and, for a given system, most all motorized roller units are interchangeable, so only one spare part is required. Conventional conveyor drive train gear motors can differ greatly in size depending on the application, conveyor type, and section length—resulting in multiple spare parts for a given system.

 

Proper Control System Strategy

A point that cannot be stressed enough is that the proper control system strategy is crucial to making a motorized roller conveyor system (or a conventional conveyor system for that matter) a complete success. The conveyor equipment industry has provided (and continues to provide) the mechanical building blocks and tools to move materials, but the control system is what makes it go, slow down, speed up, and stop when it is supposed to. The proper control system for motorized roller conveyor is distributed within each conveyor section because each section only needs to know what is going on in front of it and only needs to inform the section behind it what it is doing.

 

More Intelligence

Motorized roller conveyor solutions (and all of its inherent design benefits) are now commonly used for more intelligent functionality such as product tracking and sorting that had been the sole province of conventional conveyor systems with custom control systems. Data and information handling are maintained within the control system for a motorized roller conveyor. For example, the microcontroller in a motorized roller conveyor can digitally provide the complete roller part number containing the diameter and gearbox information, serial number, motor temperature and other information. The external control can read and analyze all this data for multiple functions such as precise speed and positioning control, full diagnostics such as over-temp, over-current, over-voltage and many other predictive maintenance parameters.

 

Better Accuracy

New technology in motorized roller conveyor controllers provides engineers the option to program positioning either by distance or time. This is valuable if you're trying to position a load or device that you are driving with the motor. While engineers are used to dealing with time-based controllers (as most manufactured models are time-based), there's often a great deal of trial and error involved in getting the load to the optimal position.

 

With a distance-based system, you can reach optimal position faster as you only have to measure where your load starts and where you wish it to end.

 

Working Smarter

Motorized roller conveyor systems offer many advantages over traditional conventional conveyor equipment schemes. These advantages in summary are:

·       Modular Design

·       Faster & Easier Installation

·       Safer

·       Quieter

·       More Energy Efficient

·       Less Maintenance Cost

·       Better Accuracy

 

These advantages alone should make the decision to implement a motorized roller conveyor solution much easier particularly for the small- to medium-sized business operation who is sure they have a material handling problem but is unsure of the next step.

 

About the Author

Pat Knapke has more than 30 years of experience in automated materials handling, most of which has been in the trenches designing and implementing conveyor control systems. He is currently the Director of Engineering for Insight Automation, a developer of innovative products for the materials handling industry, specifically, drives and controls used in low-voltage conveyors. Pat can be reached by email at pknapke@insightautomation.cc or by phone at (859) 647-8945.

Insight Automation, Inc.
2748 Circleport Dr.
Erlanger, KY 41018