On the other hand, when the electric motor inertia is bigger than the strain inertia, the electric motor will require more power than is otherwise essential for this application. This increases costs since it requires having to pay more for a engine that’s larger than precision gearbox necessary, and since the increased power consumption requires higher operating costs. The solution is by using a gearhead to match the inertia of the electric motor to the inertia of the load.
Recall that inertia is a measure of an object’s resistance to improve in its motion and is a function of the object’s mass and form. The greater an object’s inertia, the more torque is required to accelerate or decelerate the object. This implies that when the strain inertia is much bigger than the motor inertia, sometimes it could cause excessive overshoot or enhance settling times. Both conditions can decrease production line throughput.
Inertia Matching: Today’s servo motors are producing more torque in accordance with frame size. That’s due to dense copper windings, lightweight materials, and high-energy magnets. This creates better inertial mismatches between servo motors and the loads they want to move. Using a gearhead to better match the inertia of the motor to the inertia of the strain allows for utilizing a smaller motor and results in a more responsive system that’s simpler to tune. Again, this is achieved through the gearhead’s ratio, where in fact the reflected inertia of the strain to the motor is decreased by 1/ratio^2.
As servo technology has evolved, with manufacturers generating smaller, yet more powerful motors, gearheads are becoming increasingly essential companions in motion control. Locating the optimal pairing must take into account many engineering considerations.
So how really does a gearhead go about providing the power required by today’s more demanding applications? Well, that all goes back to the fundamentals of gears and their ability to alter the magnitude or direction of an applied drive.
The gears and number of teeth on each gear create a ratio. If a electric motor can generate 20 in-lbs. of torque, and a 10:1 ratio gearhead is attached to its result, the resulting torque will be close to 200 in-pounds. With the ongoing focus on developing smaller footprints for motors and the gear that they drive, the ability to pair a smaller motor with a gearhead to attain the desired torque result is invaluable.
A motor could be rated at 2,000 rpm, but your application may just require 50 rpm. Trying to perform the motor at 50 rpm may not be optimal predicated on the following;
If you are running at a very low rate, such as for example 50 rpm, and your motor feedback quality isn’t high enough, the update price of the electronic drive could cause a velocity ripple in the application form. For example, with a motor feedback resolution of just one 1,000 counts/rev you possess a measurable count at every 0.357 amount of shaft rotation. If the digital drive you are using to control the motor includes a velocity loop of 0.125 milliseconds, it’ll search for that measurable count at every 0.0375 amount of shaft rotation at 50 rpm (300 deg/sec). When it does not see that count it’ll speed up the engine rotation to think it is. At the acceleration that it finds the next measurable count the rpm will become too fast for the application and then the drive will slower the electric motor rpm back down to 50 rpm and then the complete process starts yet again. This continuous increase and decrease in rpm is exactly what will cause velocity ripple in an application.
A servo motor working at low rpm operates inefficiently. Eddy currents are loops of electric current that are induced within the engine during procedure. The eddy currents in fact produce a drag push within the electric motor and will have a larger negative effect on motor efficiency at lower rpms.
An off-the-shelf motor’s parameters may not be ideally suited to run at a minimal rpm. When an application runs the aforementioned motor at 50 rpm, essentially it isn’t using all of its offered rpm. Because the voltage continuous (V/Krpm) of the electric motor is set for an increased rpm, the torque continuous (Nm/amp), which is definitely directly linked to it-can be lower than it needs to be. Because of this the application needs more current to drive it than if the application had a motor specifically created for 50 rpm.
A gearheads ratio reduces the engine rpm, which is why gearheads are sometimes called gear reducers. Using a gearhead with a 40:1 ratio, the electric motor rpm at the input of the gearhead will end up being 2,000 rpm and the rpm at the output of the gearhead will end up being 50 rpm. Working the engine at the bigger rpm will allow you to prevent the problems mentioned in bullets 1 and 2. For bullet 3, it enables the look to use much less torque and current from the engine based on the mechanical benefit of the gearhead.