How Can A High-Torque Motor Have Low a low RPM

[012anonymousx]

Torque is the rotational force.
If there is more force, how can the motor be slow?

I'm building a DC motor and read that given a constant amount of coil, creating a very dense coil will increase torque but lower RPMs.
Conversely, making it looser (bigger radius) increases RPM but lowers torque.

 

[Simon Bridge]

The torque gives you acceleration - but it is possible to accelerate to any speed... however slow.

For your motor - it will accelerate to a constant speed due to losses that are proportional to speed. This will be proportional to the amount of mass that has to be spun - and so is the torque.

 

[rcgldr]

The increase in torque at lower rpm is offset by increase in back emf at higher rpm, which decreases the torque at higher rpm.

 

[russ_watters]

Motors are connected to loads. The load determines the ratio between RPM and torque. If a "high torque" motor is not connected to a load and is just allowed to freewheel, it does not produce any torque.

 

[PJC01]

I can explain this phenomenon using the equation for torque: T = rFsinθ, where T is torque, r is the radius of the coil, F is the force applied, and θ is the angle between the force and the lever arm (in this case, the radius of the coil).

In a high-torque motor, the radius of the coil is smaller, meaning that the force is applied closer to the center of rotation. This results in a higher torque, as the lever arm (radius) is smaller. However, because the force is applied closer to the center, the rotational speed (RPM) is lower.

On the other hand, in a low-torque motor with a larger radius coil, the force is applied further from the center of rotation, resulting in a smaller torque. However, because the force is applied further from the center, the rotational speed is higher.

Therefore, the density or tightness of the coil does not directly affect the torque or RPM of the motor. It is the radius of the coil that plays a crucial role in determining the torque and RPM of the motor.