However, when the precision gearbox electric motor inertia is larger than the strain inertia, the electric motor will require more power than is otherwise essential for the particular application. This raises costs since it requires having to pay more for a engine that’s bigger than necessary, and since the increased power consumption requires higher working costs. The solution is by using 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 improve in its movement and is a function of the object’s mass and form. The higher an object’s inertia, the more torque is required to accelerate or decelerate the thing. This means that when the strain inertia is much larger than the electric motor inertia, sometimes it can cause extreme overshoot or enhance settling times. Both circumstances can decrease production range throughput.
Inertia Matching: Today’s servo motors are generating more torque in accordance with frame size. That’s due to dense copper windings, lightweight materials, and high-energy magnets. This creates greater inertial mismatches between servo motors and the loads they are trying to move. Using a gearhead to better match the inertia of the electric motor to the inertia of the strain allows for using a smaller electric motor and results in a more responsive system that's easier to tune. Again, this is accomplished 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 are becoming increasingly essential companions in motion control. Finding the ideal pairing must consider many engineering considerations.
So how will 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 capability to change the magnitude or direction of an applied force.
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 mounted on its output, the resulting torque will be close to 200 in-pounds. With the ongoing emphasis on developing smaller sized footprints for motors and the equipment that they drive, the capability to pair a smaller motor with a gearhead to achieve the desired torque output is invaluable.
A motor may be rated at 2,000 rpm, however your application may just require 50 rpm. Attempting to perform the motor at 50 rpm might not be optimal predicated on the following;
If you are operating at an extremely low velocity, 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. For example, with a motor feedback resolution of 1 1,000 counts/rev you possess a measurable count at every 0.357 amount of shaft rotation. If the electronic drive you are employing to regulate the motor has a velocity loop of 0.125 milliseconds, it will search for that measurable count at every 0.0375 amount of shaft rotation at 50 rpm (300 deg/sec). When it generally does not observe that count it'll speed up the engine rotation to find it. At the quickness that it finds another measurable count the rpm will end up being too fast for the application form and the drive will slow the electric motor rpm back off to 50 rpm and the whole process starts all over again. This continuous increase and reduction in rpm is what will cause velocity ripple in 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 pressure within the electric motor and will have a larger negative impact on motor overall performance at lower rpms.
An off-the-shelf motor’s parameters might not be ideally suited to run at a low rpm. When a credit card applicatoin runs the aforementioned engine at 50 rpm, essentially it is not using all of its available rpm. Because the voltage constant (V/Krpm) of the electric motor is set for an increased rpm, the torque continuous (Nm/amp), which is definitely directly linked to it-is certainly lower than it needs to be. As a result the application needs more current to drive it than if the application form had a motor particularly made 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 motor rpm at the input of the gearhead will become 2,000 rpm and the rpm at the output of the gearhead will end up being 50 rpm. Operating the electric motor at the bigger rpm will allow you to avoid the worries mentioned in bullets 1 and 2. For bullet 3, it allows the look to use less torque and current from the engine based on the mechanical benefit of the gearhead.