CHOOSING YOUR MOTOR
Gearbox Thermal Limits are a limiting factor when using motor gearboxes in excess of the normal continuous S1 duty cycle. This continuous duty cycle is most likely the duty cycle displayed in the Torque Speed graph, but Parvalux has many years’ experience optimisation of the application and has comprehensive data on our gearboxes for intermittent use. Approximate Parvalux gearbox rating limits can be calculated for both continuous and intermittent duty cycle by using information below:
Efficiency of both the motor and the gearbox and the combined efficiency is a topic in its own right, but essentially normally more than the performance variables need to be included in the selection process. Parvalux has great experience in comparing the different motor and gearbox technologies and assessing the trade-off between them in a given application. Parvalux’s experience in supplying many industries is unprecedented and quickly allows discussions on the correct technology for the application. For OEMs requiring large volumes, ‘Technology Rigs’ can be constructed using different technologies to empirically compare data in the application, but many non-performance variables inevitably need to be added to the selection process when seeking ultimate efficiencies (costs, marketing benefits, system complexity etc).
A very simplified example of the ‘trade-offs’ when considering efficiency is displayed in a Battery Operated Winch example below.
This example is certainly subjective, written in context to a battery operated winch and not exhaustive, but demonstrates other factors when considering efficiency. There are also only two technology combinations considered although many others motor/gearbox technolog combinations could be compared. When comparing technology groups for ultimate efficiency you may wish to select a brushless motor with epicyclic gearbox, which in general, would give you the best efficiency but at additional cost and complexity. For example, being a winch it may need to self-sustain (not move when the power if off but the load is still applied) which a worm-wheel gearbox can achieve due to its inefficiencies. The epicyclic gearbox may well not self-sustain due to its increased efficiency, therefore requiring extra items such as a mechanical brake and all the control complexities that go with it. The cost of the additional brake, its control, along with the PWM controller for the brushless motor, can be considerable when compared to the simplicity of Permanent DC Motor & Worm Wheel Gearbox. Parvalux’s experience with the many technologies we can offer will save you time when selecting the most appropriate motor and gearbox technology for your application