On the other hand, when the electric motor inertia is bigger than the load inertia, the electric motor will require more power than is otherwise necessary for this application. This increases costs because it requires paying more for a electric motor that’s larger than necessary, and since the increased power usage requires higher operating costs. The solution is to use a servo gearhead gearhead to complement the inertia of the motor to the inertia of the load.
Recall that inertia is a measure of an object’s level of resistance to change in its movement and is a function of the object’s mass and form. The higher an object’s inertia, the more torque is needed to accelerate or decelerate the thing. This implies that when the load inertia is much bigger than the electric motor inertia, sometimes it could cause extreme overshoot or increase settling times. Both conditions can decrease production range throughput.
Inertia Matching: Today’s servo motors are producing more torque in accordance with frame size. That’s because of dense copper windings, lightweight materials, and high-energy magnets. This creates greater inertial mismatches between servo motors and the loads they want to move. Using a gearhead to raised match the inertia of the engine to the inertia of the load allows for utilizing a smaller electric motor and results in a far more responsive system that is easier to tune. Again, this is attained through the gearhead’s ratio, where the reflected inertia of the strain to the engine is decreased by 1/ratio^2.
As servo technology has evolved, with manufacturers generating smaller, yet better motors, gearheads have become increasingly essential partners in motion control. Locating the optimal pairing must take into account many engineering considerations.
So how does a gearhead start providing the power required by today’s more demanding applications? Well, that goes back again to the basics of gears and their ability to modify the magnitude or direction of an applied push.
The gears and number of teeth on each gear create a ratio. If a motor can generate 20 in-pounds. of torque, and a 10:1 ratio gearhead is mounted on its output, the resulting torque can be close to 200 in-lbs. With the ongoing emphasis on developing smaller footprints for motors and the equipment that they drive, the ability to pair a smaller engine with a gearhead to achieve the desired torque output is invaluable.
A motor could be rated at 2,000 rpm, however your application may only require 50 rpm. Trying to run the motor at 50 rpm might not be optimal based on the following;
If you are working at an extremely low acceleration, such as 50 rpm, and your motor feedback quality isn’t high enough, the update price of the electronic drive may cause a velocity ripple in the application. For instance, with a motor feedback resolution of 1 1,000 counts/rev you possess a measurable count at every 0.357 degree of shaft rotation. If the electronic drive you are employing to control the motor has a velocity loop of 0.125 milliseconds, it will look for that measurable count at every 0.0375 degree of shaft rotation at 50 rpm (300 deg/sec). When it does not discover that count it will speed up the engine rotation to think it is. At the velocity that it finds the next measurable count the rpm will become too fast for the application and then the drive will sluggish the engine rpm back down to 50 rpm and then the complete process starts yet again. This constant increase and reduction in rpm is exactly what will cause velocity ripple within an application.
A servo motor operating at low rpm operates inefficiently. Eddy currents are loops of electric current that are induced within the motor during operation. The eddy currents actually produce a drag force within the motor and will have a greater negative impact on motor functionality at lower rpms.
An off-the-shelf motor’s parameters may not be ideally suitable for run at a minimal rpm. When a credit card applicatoin runs the aforementioned electric motor at 50 rpm, essentially it is not using all of its offered rpm. As the voltage continuous (V/Krpm) of the engine is set for a higher rpm, the torque continuous (Nm/amp), which is certainly directly linked to it-can be lower than it requires to be. As a result the application requirements more current to operate a vehicle 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 be 2,000 rpm and the rpm at the output of the gearhead will become 50 rpm. Working the engine at the bigger rpm will enable you to prevent the worries mentioned in bullets 1 and 2. For bullet 3, it enables the design to use much less torque and current from the engine based on the mechanical benefit of the gearhead.