However, when the motor inertia is larger than the strain inertia, the engine will require more power than is otherwise necessary for the particular application. This boosts costs since it requires spending more for a engine that’s bigger than necessary, and because the increased power intake requires higher operating costs. The solution is to use a gearhead to match the inertia of the motor 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 shape. The greater an object’s inertia, the more torque is needed to accelerate or decelerate the thing. This implies that when the load inertia is much larger than the electric motor inertia, sometimes it can cause extreme overshoot or boost 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, light-weight materials, and high-energy magnets. This creates better inertial mismatches between servo motors and the loads they want to move. Utilizing a gearhead to better match the inertia of the engine to the inertia of the strain allows for utilizing a smaller electric motor and results in a more responsive system that’s simpler 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 creating smaller, yet better motors, gearheads have become increasingly essential partners in motion control. Finding the optimum pairing must consider many engineering considerations.
So how will a gearhead start providing the energy required by today’s more demanding applications? Well, that all 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-lbs. of torque, and a 10:1 ratio gearhead is attached to its result, the resulting torque will be close to 200 in-pounds. With the ongoing emphasis on developing smaller footprints for motors and the equipment that they drive, the capability to pair a smaller motor with a gearhead to attain the desired torque result is invaluable.
A motor may be rated at 2,000 rpm, but your application may just require 50 rpm. Trying to run the motor at 50 rpm might not be optimal predicated on the following;
If you are operating at a very low velocity, such as 50 rpm, as well as your motor feedback quality is not high enough, the update price of the electronic drive may cause a velocity ripple in the application form. For instance, with a motor feedback resolution of just one 1,000 counts/rev you have a measurable count at every 0.357 degree of shaft rotation. If the electronic drive you are employing to regulate the motor includes a velocity loop of 0.125 milliseconds, it’ll search for that measurable count at every 0.0375 degree of shaft rotation at 50 rpm (300 deg/sec). When it generally does not see that count it will speed up the engine rotation to think it is. At the quickness that it finds the next measurable count the rpm will become too fast for the application and the drive will slow the electric motor rpm back off to 50 rpm and then the whole process starts all over again. This continuous increase and reduction in rpm is exactly what will trigger velocity ripple within an application.
A servo motor operating at low rpm operates inefficiently. Eddy currents are loops of electrical current that are induced within the engine during operation. The eddy currents in fact produce a drag pressure within the engine and will have a larger negative effect on motor efficiency at lower rpms.
An off-the-shelf motor’s parameters may not be servo gearhead ideally suitable for run at a low rpm. When a credit card applicatoin runs the aforementioned electric motor at 50 rpm, essentially it isn’t using most of its offered rpm. As the voltage continuous (V/Krpm) of the motor is set for an increased rpm, the torque continuous (Nm/amp), which is definitely directly related to it-can be lower than it needs to be. Consequently the application requirements more current to drive it than if the application form had a motor specifically created for 50 rpm.
A gearheads ratio reduces the electric 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 insight of the gearhead will be 2,000 rpm and the rpm at the result of the gearhead will be 50 rpm. Operating the motor at the higher rpm will enable you to prevent the concerns mentioned in bullets 1 and 2. For bullet 3, it allows the design to use much less torque and current from the engine based on the mechanical advantage of the gearhead.