Name: Automatic Door Opener

The customer wanted a simplified, low-cost Variable Frequency Drive for his semi-automatic door openers.

Overview: An automatic door opener for public building access requires various stages of operation. When the user pushes the button, the door must open, stay open for a period of time, and then close. Operation must also take into consideration all human, mechanical, or nature made obstacles such as wind and snow.

The application benefit: By integrating all of the above-described actions, the operation would be improved, external hardware minimized, and costs lowered.

The customer's product: The customer's product is a pneumatic door closer for public access in and out of buildings.

The customer's present solution: The customer's product combines a manual door opener with a mechanical pneumatic door closer. The customer's request was to integrate the mechanical sequencing action into a Variable Frequency Drive (VFD).

KB installed the customer's door opener in the KB lab and extensively tested the door motion while measuring the motor parameters during operation. The KBVF software was customized to duplicate the desired sequencing.

KB's capabilities for solving the problem: It's the KBVF Adjustable Frequency Drive (AFD) series. This series incorporates a powerful, second-generation, micro-controller that is programmable for custom OEM applications using software that has proprietary motor monitoring capabilities. KB's engineering staff has a reputation of working directly with customer applications to reach satisfactory solutions.

The KB solution: The objective was to integrate all of the control logic into the Variable Frequency Drive software, thereby eliminating excessive hardware such as: a mini PLC, 2 DPDT relays, 2 limit switches, and extensive wire harnesses. The software was designed to unlatch the door lock after a programmed delay once the 'OPEN' button was pushed, and to open and hold the door open for a preprogrammed period of time. After the specified time, the VFD released the opening mechanism allowing the pneumatic closer to close the door. If the door encountered an obstacle while closing, the KBVF software would sense an increase in torque and reverse the direction of the door. Setting up right or left door opening conditions also required accurate torque measurements in both directions.

The results: Using the modified KBVF-21D with SIVFR, the customer has a low-cost semi automatic door motion product with all of the mechanical control functions integrated into the KBVF's customized software.

Customer's strategic advantage: The customer got exactly what he wanted no more, no less - plus he enjoyed improved reliability, a space-saving design, and reduced installation costs; all of which gave him a major advantage over the competition.

A Win-Win solution for both the customer and KB.