On the other hand, when the motor inertia is larger than the strain inertia, the engine will need more power than is otherwise necessary for the particular application. This boosts costs because it requires having to pay more for a engine that’s larger than necessary, and since the increased power usage requires higher operating costs. The solution is by using a servo gearhead gearhead to complement the inertia of the engine to the inertia of the strain.
Recall that inertia is a measure of an object’s level of 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 object. This means that when the load inertia is much larger than the engine inertia, sometimes it could cause extreme overshoot or boost settling times. Both circumstances 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, light-weight materials, and high-energy magnets. This creates higher 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 using a smaller motor and results in a more responsive system that’s easier to tune. Again, that is accomplished 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 making smaller, yet more powerful motors, gearheads are becoming increasingly essential partners in motion control. Finding the ideal 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 goes back again to the basics of gears and their capability to modify the magnitude or direction of an applied power.
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 will be near to 200 in-lbs. 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 result is invaluable.
A motor could be rated at 2,000 rpm, however your application may only require 50 rpm. Attempting to perform the motor at 50 rpm may not be optimal predicated on the following;
If you are running at a very low speed, such as 50 rpm, and your motor feedback quality is not high enough, the update rate of the electronic drive may cause a velocity ripple in the application. For instance, with a motor opinions 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 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 generally does not discover that count it will speed up the engine rotation to find it. At the rate that it finds the next measurable count the rpm will end up being too fast for the application form and the drive will slower the motor rpm back down to 50 rpm and then the whole process starts yet again. This continuous increase and decrease in rpm is exactly what will trigger velocity ripple in an application.
A servo motor running at low rpm operates inefficiently. Eddy currents are loops of electric current that are induced within the electric motor during procedure. The eddy currents actually produce a drag drive within the motor and will have a greater negative effect on motor overall performance at lower rpms.
An off-the-shelf motor’s parameters might not be ideally suitable for run at a minimal rpm. When an application runs the aforementioned engine at 50 rpm, essentially it isn’t using most of its available rpm. Because the voltage constant (V/Krpm) of the electric motor is set for a higher rpm, the torque constant (Nm/amp), which is directly related to it-can be lower than it requires to be. Consequently the application needs more current to drive it than if the application form had a motor particularly designed for 50 rpm.
A gearheads ratio reduces the motor rpm, which explains why gearheads are sometimes called gear reducers. Using a gearhead with a 40:1 ratio, the engine rpm at the input of the gearhead will end up being 2,000 rpm and the rpm at the output of the gearhead will be 50 rpm. Operating the motor at the bigger rpm will permit you to prevent the worries mentioned in bullets 1 and 2. For bullet 3, it enables the look to use less torque and current from the motor based on the mechanical advantage of the gearhead.