A mobile platform lift cart was designed by one of our motion partners which used a large electric linear actuator for lifting equipment precisely for a manufacturing process. Shift Controls was approached to design a control panel to control this actuator, monitor limit switches, operator commands, and provide equipment safety. The whole system was designed to be modular, mobile, and powered by rechargeable batteries. Shift Controls developed mechanical drawings and wiring diagrams for project approval to ensure all the design requirements were met before construction began.
Safety Design
Since this lift would be operated in close proximity to personnel, safety was paramount. Shift Controls designed a safety system controlled by a safety relay with a panel mounted E-Stop, remote E-Stops, and an electronic brake release. A push from any of the three E-Stop buttons would de-energize the safety relay opening all the safety enabling paths. This would de-energize the safety contactor de-energizing the linear actuator driver, motor and electric brake release. This would stop the motor and the brake would clamp the motor output shaft so the lift platform would not back drive. The safety contactor state was monitored by the safety relay for the system to be restarted.
Electrical Design
The mobile lift cart was specified by the end customer to be battery powered and to be easily rechargeable. Shift Controls’ motion partners specified the linear actuator package, battery, and charger. Shift Controls designed a separate battery panel with integrated current protection in addition to the main control panel which included the logic, the safety system, and the operator control and sensor integration terminals. This modular design allowed a larger or smaller battery system to be easily implemented for future builds.
Separate operator button stations were designed and constructed for the operator to control the platform lift when positioning the equipment. The panels could then be mounted where they would not interfere with the operation. Terminal blocks were provided to easily provide power and interface all the field devices together. This made the panel installation and integration extremely simple.
Field Sensor Integration
Shift Controls prioritizes ease of field installation for all of its designs and this panel was designed to have all the field terminations located on the top side of the enclosure. Terminal blocks were used to breakout all the multi-pin drive interfacing connectors. This allowed the customer to simply land the field wires on labeled terminal blocks instead of routing and soldering all the field connections in connectors, saving countless hours and troubleshooting during the installation. The motor power, electronic brake, limit switches, operator buttons, and the remote E-Stop cables all passed through a cable gland plate.
Outcome
The system was fully commissioned with a test motor and sensors at Shift Controls before the panel was delivered to the customer to ensure the system operated as designed before the install. Shift Controls assisted in the field wiring of the components and commissioning of the lift platform before it was delivered to the end customer. The end customer was extremely satisfied with the design and how the system operates. Based on the success of this project, the customer will be installing more of these systems in the future.
Custom Designs
Shift Controls has extensive experience in designing and fabricating custom UL508A panels to meet the most difficult design and environmental requirements. Like this project, we listen to your specific project requirements and custom design a system that meets your process and cost requirements. As always, feel free to contact us regarding your project or if you have any questions.
