However, when the electric motor inertia is larger than the load inertia, the electric motor will require more power than is otherwise essential for the particular application. This increases costs since it requires having to pay more for a motor that’s bigger than necessary, and because the increased power intake requires higher working costs. The solution is to use a gearhead to match the inertia of the engine to the inertia of the load.
Recall that inertia is a measure of an object’s resistance to change in its movement and is a function of the object’s mass and form. The greater an object’s inertia, the more torque is needed to accelerate or decelerate the object. This implies that when the strain inertia is much larger than the motor inertia, sometimes it could cause excessive overshoot or boost settling times. Both circumstances can decrease production collection throughput.
Inertia Matching: Today’s servo motors are generating more torque relative to frame size. That’s due to dense copper windings, lightweight materials, and high-energy magnets. This servo gearhead creates better inertial mismatches between servo motors and the loads they want to move. Utilizing a gearhead to raised match the inertia of the motor to the inertia of the load allows for utilizing a smaller electric motor and outcomes in a more responsive system that is simpler to tune. Again, that is achieved through the gearhead’s ratio, where in fact the reflected inertia of the load to the electric motor is decreased by 1/ratio^2.
As servo technology has evolved, with manufacturers generating smaller, yet better motors, gearheads have become increasingly essential companions in motion control. Finding the optimal pairing must consider many engineering considerations.
So how really does a gearhead go about providing the energy required by today’s more demanding applications? Well, that all goes back again to the fundamentals 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 engine can generate 20 in-lbs. of torque, and a 10:1 ratio gearhead is attached to its output, the resulting torque can be close to 200 in-lbs. With the ongoing emphasis on developing smaller footprints for motors and the gear that they drive, the ability to pair a smaller electric motor with a gearhead to achieve the desired torque result is invaluable.
A motor could be rated at 2,000 rpm, but your application may only require 50 rpm. Attempting to run the motor at 50 rpm may not be optimal predicated on the following;
If you are working at a very low acceleration, such as 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. 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 digital drive you are using to regulate the motor includes a velocity loop of 0.125 milliseconds, it will search for that measurable count at every 0.0375 degree of shaft rotation at 50 rpm (300 deg/sec). When it generally does not find that count it will speed up the engine rotation to think it is. At the speed that it finds another measurable count the rpm will end up being too fast for the application and then the drive will gradual the electric motor rpm back off to 50 rpm and the whole process starts all over again. This constant increase and reduction in rpm is exactly what will trigger velocity ripple within an application.
A servo motor working at low rpm operates inefficiently. Eddy currents are loops of electrical current that are induced within the engine during procedure. The eddy currents actually produce a drag push within the engine and will have a larger negative effect on motor functionality at lower rpms.
An off-the-shelf motor’s parameters might not be ideally suited to run at a low rpm. When an application runs the aforementioned motor at 50 rpm, essentially it isn’t using most of its available rpm. As the voltage continuous (V/Krpm) of the motor is set for an increased rpm, the torque continuous (Nm/amp), which is certainly directly related to it-is usually lower than it requires to be. As a result the application needs more current to operate a vehicle it than if the application had a motor particularly designed for 50 rpm.
A gearheads ratio reduces the engine rpm, which is why gearheads are occasionally called gear reducers. Utilizing 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. Operating the motor at the higher rpm will enable you to prevent the problems mentioned in bullets 1 and 2. For bullet 3, it allows the design to use less torque and current from the electric motor predicated on the mechanical advantage of the gearhead.