Browning recently introduced an expanded range of sizes at AHR for its self-tensioning Tenso-set motor base. The expanded product range for the energy-saving Tenso-set base will include up to NEMA 447 and equivalent IEC motor frame sizes. At AHR, the Tenso-set base with its quick-release (QR) option – available for NEMA frame sizes up to 286 – will be matched against a standard base of equal size in a belt-change run-off called the Tenso-set Challenge. Product enhancements for the quick-release models will also be highlighted at the show. 

"We will have demonstrations at the show on side-by-side identical belt drives with an industry-standard base and another with the Tenso-set quick-release base," said Browning Director of Marketing Don Sullivan. "We will also be running belt-change speed contests on this setup to give technicians hands-on experience and a chance to see what a life-changer a one-minute belt change can be. We will award interim prizes as well as a grand prize for the fastest belt change performed during the show.

"We added a jam nut on the adjusting rod to hold tension on the spring system before releasing belt tension with the adjusting nut on the rod. The technician simply spins the jam nut forward against the carriage, gives it a turn or two to compress the spring further, and this relieves tension on the adjusting nut so it's easier to loosen. With the quick-release Tenso-set model, we are able to change belts on a 20-hp motor in about a minute with this improved design – around one-sixth the normal time."

The Tenso-set base is a drop-in replacement for most standard motor bases, and utilizes the same jackscrew design to adjust and hold tension on the belt. However, the Tenso-set base includes a coil spring inside the screw housing that pushes against the carriage to maintain tension as the belt naturally breaks-in and seats itself further into the sheave groove due to loss of mass.

"The Tenso-set design helps eliminate the need for frequent belt re-tensioning, including during the first 24 hours of run time, which saves the maintenance staff at least one service call," said Sullivan. "More important for the building owner, it better maintains the drive's energy efficiency by preventing the normal tension loss that occurs over time. Some of the largest commercial buildings in the U.S. are already testing this base to determine ROI."

The QR option for the base allows release of all belt tension after just a few turns of the tensioning screw. The QR base has a patent-pending sliding gate that covers a cutout in the motor frame. This allows the head of the tensioning screw to pass through the base, so the carriage easily slides forward to slacken the belts. After belt installation, the carriage can be moved back and the sliding gate closed to retain the head of the jackscrew for tensioning.