Hello! I have the following questions:
I want to apply a certain load with an electric actuator, modifying the voltage with a potentiometer, but due to the design of the structure, I cannot put the load cell to see what load I am applying, my question is: if I measure the load applied by the actuator at a certain voltage with the load cell in a separate experiment, let’s say that at 6V the load cell tells me that the actuator is applying 100 kg in compression, when I put the actuator in the structure that it should be, will I also be applying those 100 kg if the actuator is working at 6V?
And the other question is about proportionality, if the load cell tells me that at 6V the actuator is providing 100 kg of compressive force, can I say that at 12 V the actuator will be providing 200 kg of force?
Thank you so much.
Hello @albertoserrano and welcome to the RobotShop community,
First of all, let’s clarify a few things about DC motors. The voltage rating of a motor indicates the most efficient voltage while running and it is recommended to use the nominal/rated voltage of the motor. If you apply too few volts, the motor will not work, whereas too many volts can short windings resulting in power loss or complete destruction.
Also, in any motor, the basic principles are that the speed is proportional to the voltage applied, and the torque is proportional to current pulled. This means that increasing the voltage applied will increase the speed of the motor, not the torque. To get more torque you would need to supply your motor with more current, however, current is a value that cannot be easily controlled. DC motors use only as much current as they need. Motors specifications include this curve, for example, an L12 linear actuator has these curves:
The maximum current a motor can tolerate is called nominal/rated current, which is significantly lower than the motor stall current. A motor that is prevented from turning will consume maximum/stall current and produce the maximum torque possible. How much current a motor can tolerate when a voltage is applied depends on how much thick the coils are (thicker = higher current = higher torque).
I think that answers your second question, which in a few words is no, doubling the voltage applied will not double the torque that the actuator can apply.
And as for the first question, if the goal is to compress the same object with the same actuator in the same structure, then yes, if you use the same voltage the actuator should apply the same force.
I hope that information can help you!
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Hi! Thank you very much and sorry for the delay. Your answer helps me a lot. Thank you again for such an elaborated answer.
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