For nearly 20 years, packagers have relied on Econocorp’s Spartan cartoner. Last year the machine experienced its third major upgrade, adding a 1-hp Kebco alternating current (AC) frequency inverter that drives one 3?4-hp AC gear motor from SEW-Eurodrive.
The frequency inverter varies the megahertz frequency available to the AC gear motor, thus regulating the speed at which the motor operates. It’s the motor that moves chains, cartons, and product from one station to another within the machine.
“Previously we had used a gearbox,” explains Brian Elfast, Econocorp’s vice president of operations. “Attached to the gearbox was a speed reducer, a clutch brake, clutch brake power supply, drive motor, and all the associated chains and linkages required. The acceleration and deceleration of the chains were fixed, the gearbox was noisy, and it had a tendency to require maintenance.”
Elfast says Econocorp wanted to provide its customers with more flexibility in running the machine. “We looked at all servo drives, but they were pricey,” he notes. “AC inverters were relatively expensive three or four years ago, but the pricing has come down, and the accuracy, which is a key, has gone up.”
He says that accuracy is important in the indexing cycle of the machine. For example, “If the carton isn’t in the right position, the product won’t load, or when you go to seal the carton, it ends up not square,” Elfast says.
“We tested out a few manufacturers’ inverters and gearboxes and selected the Kebco frequency inverter to drive the AC gear motor from SEW because they make a nice pair,” he says. Indexing functions are controlled through an Allen-Bradley PLC that uses high-speed proximity sensors for stopping. It’s supplied by Rockwell Automation.
“The gear motor has a low inertia so it’s fairly easy to start and stop accurately,” says the Econocorp vice president. “Between both of them we were able to get the indexing accuracy we weren’t able to get from other manufacturers. Kebco says it’s because they use proprietary software that is able to analyze indexing and stop the machine at the same spot every time.”
The previous gear motor, he points out, just turned on and off. “With an inverter, we’re able to ramp up and back down. Not only is this process smoother, but we’re able to obtain higher speed from the gearbox to the AC inverter,” says Elfast. “So we’ve gone from 40 up to 52 cartons per minute.”
There are also economic advantages with the inverter technology. “It’s faster, it’s just as accurate, requires less maintenance for the customer, and it actually avoided a cost increase [for customers],” Elfast says.
The enhanced Spartan cartoner accommodates paperboard folding cartons in length, width, and depth dimensions ranging from 2”x1”x4” up to 10”x4”x12”.
“This new version was first out in the field about a year ago,” Elfast recalls. “We’ve had lots of comments back from the field. They [customers] love that it’s quiet, and they’ve commented about the lack of maintenance that’s required.”
