300 1152x882 [font=Arial,sans-serif]Hi there,[/font]
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[font=Arial,sans-serif]I am building 2 pendulums for a theater production. Ideally they would be some 26 ft long. We made a test with an electric tube linear actuator incl. slide rail mounted to the ceiling and a hinged 10 ft aluminum tube attached to the rod/plunger of the actuator. The actuator was controlled by a simple DPDT relay.[/font]
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[font=Arial,sans-serif]The actuator used was Firingelli’s high-speed actuator with the following specs:[/font]
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[font=Arial,sans-serif]Dynamic Force: 22 lb[/font]
[font=Arial,sans-serif]Static Force: 44 lb[/font]
[font=Arial,sans-serif]Speed ("/S): 4.5" (9" at no load)[/font]
[font=Arial,sans-serif]Current: 5A max[/font]
[font=Arial,sans-serif]Duty Cycle: 20% at 100% load, 50% at 25% of load[/font]
[font=Arial,sans-serif]Input: 12v DC[/font]
[font=Arial,sans-serif]Stroke: 10 in[/font]
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[font=Arial,sans-serif]See firgelliauto.com/products/h … d-actuator[/font]
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[font=Arial,sans-serif]It works quite well as long as you make sure you don’t go over the 20% duty cycle.[/font]
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[font=Arial,sans-serif]Once we tried out a 26 ft pendulum the stroke speed was unfortunately too slow to produce a significant pendulum swing.[/font]
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[font=Arial,sans-serif]We also tested a different model with similar specs from Progressive Automations with a 16 inch stroke which actually made the pendulum swing less (see - progressiveautomations.com/t … uator)[/font]
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[font=Arial,sans-serif]My guess is that a higher speed and duty cycle would significantly improve the results. We’ve actually tried higher duty cycles up to 60% and achieved a much longer pendulum swing, at least for a while before the actuator burned out. Ouch![/font]
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[font=Arial,sans-serif]Question to the forum: Do you know of an electric high speed actuators 4 in/sec or more, 22 lbs or more and a duty cycle 20% or (much) more?[/font]
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[font=Arial,sans-serif]I am aware that a pneumatic control would be much better but considering my deadline and the potential noise from a pneumatic actuator I try to stick to electric at this point.[/font]
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[font=Arial,sans-serif]Do you maybe know another forum outside of Robotshop that might be able to help out?[/font]
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[font=Arial,sans-serif]Thank you for your help in advance![/font]
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[font=Arial,sans-serif]Erwin[/font]
You gave yourself the same advice we would give; most DC motor based linear actuators have a very low duty cycle, so a pneumatic system would completely change that. Industrial linear actuators use coreless or brusheless DC motors which can withstand a lot more, but cost an order of magnitude more as well.
This seems rather easy to fix with a geared variable speed motor and a set of adjustable progressive arms to achieve the amount of stroke needed. Could have used pulleys and wire or rope to pull in both directions similar to a winch motor except you’d wind and unwind at the same time.
John