On the other hand, when the motor inertia is larger than the load inertia, the electric motor will require more power than is otherwise essential for this application. This increases costs because it requires spending more for a motor that’s larger than necessary, and since the increased power intake requires higher operating costs. The solution is to use 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 level of 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 thing. This means that when the load inertia is much larger than the engine inertia, sometimes it could cause excessive overshoot or enhance settling times. Both conditions can decrease production series throughput.
Inertia Matching: Today’s servo motors are generating 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 are trying to move. Using a gearhead to better match the inertia of the motor to the inertia of the strain allows for using a smaller engine and outcomes in a far 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 strain to the motor is precision gearbox decreased by 1/ratio^2.
As servo technology has evolved, with manufacturers making smaller, yet more powerful motors, gearheads are becoming increasingly essential companions in motion control. Finding the optimum pairing must consider many engineering considerations.
So how really does a gearhead start providing the energy required by today’s more demanding applications? Well, that goes back again to the fundamentals of gears and their ability to alter the magnitude or path of an applied force.
The gears and number of teeth on each gear create a ratio. If a electric 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 focus on developing smaller sized footprints for motors and the equipment that they drive, the capability to pair a smaller electric motor with a gearhead to achieve the desired torque output is invaluable.
A motor could be rated at 2,000 rpm, however your application may just require 50 rpm. Attempting to run the motor at 50 rpm may not be optimal predicated on the following;
If you are running at an extremely low speed, such as for example 50 rpm, as well as your motor feedback resolution 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 have a measurable count at every 0.357 amount of shaft rotation. If the electronic drive you are employing to regulate the motor includes a velocity loop of 0.125 milliseconds, it will look for that measurable count at every 0.0375 amount of shaft rotation at 50 rpm (300 deg/sec). When it does not discover that count it will speed up the engine rotation to find it. At the velocity that it finds another measurable count the rpm will end up being too fast for the application form and then the drive will slow the motor rpm back down to 50 rpm and then the complete process starts yet again. This continuous increase and reduction in rpm is what will trigger velocity ripple in an application.
A servo motor running at low rpm operates inefficiently. Eddy currents are loops of electrical current that are induced within the motor during procedure. The eddy currents actually produce a drag power within the engine and will have a greater negative impact on motor overall performance at lower rpms.
An off-the-shelf motor’s parameters may not be ideally suited to run at a low rpm. When a credit card applicatoin runs the aforementioned motor at 50 rpm, essentially it is not using most of its offered rpm. Because the voltage continuous (V/Krpm) of the electric motor is set for a higher rpm, the torque continuous (Nm/amp), which is 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 had a motor specifically made for 50 rpm.
A gearheads ratio reduces the motor rpm, which explains 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 be 2,000 rpm and the rpm at the result of the gearhead will end up being 50 rpm. Working the motor at the higher rpm will enable you to prevent the issues mentioned in bullets 1 and 2. For bullet 3, it enables the design to use much less torque and current from the electric motor based on the mechanical advantage of the gearhead.