On the other hand, when the electric motor inertia is bigger than the servo gearhead strain inertia, the engine will require more power than is otherwise essential for this application. This increases costs because 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 electric motor to the inertia of the strain.
Recall that inertia is a measure of an object’s resistance to change in its motion and is a function of the object’s mass and shape. The higher an object’s inertia, the more torque is needed to accelerate or decelerate the object. This implies that when the load inertia is much larger than the motor inertia, sometimes it could cause excessive overshoot or enhance settling times. Both circumstances can decrease production range 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 creates greater inertial mismatches between servo motors and the loads they are trying to move. Using a gearhead to raised match the inertia of the electric motor to the inertia of the strain allows for using a smaller engine and outcomes in a far more responsive system that is easier to tune. Again, that is accomplished through the gearhead’s ratio, where in fact the reflected inertia of the strain to the motor is decreased by 1/ratio^2.
As servo technology has evolved, with manufacturers making smaller, yet more powerful motors, gearheads have become increasingly essential companions in motion control. Locating the optimal pairing must take into account many engineering considerations.
So how really does a gearhead go about providing the energy required by today’s more demanding applications? Well, that goes back to the fundamentals of gears and their capability to change the magnitude or path of an applied drive.
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 mounted on its output, the resulting torque can be near 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 motor with a gearhead to attain the desired torque result is invaluable.
A motor may be rated at 2,000 rpm, however 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 running at an extremely low rate, 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 example, with a motor opinions resolution of 1 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 will look for that measurable count at every 0.0375 degree of shaft rotation at 50 rpm (300 deg/sec). When it does not observe that count it’ll speed up the electric motor rotation to find it. At the swiftness that it finds another measurable count the rpm will end up being too fast for the application and then the drive will sluggish the motor rpm back off to 50 rpm and the complete process starts yet again. This constant increase and decrease in rpm is exactly what will cause velocity ripple in an application.
A servo motor operating at low rpm operates inefficiently. Eddy currents are loops of electrical current that are induced within the motor during operation. The eddy currents in fact produce a drag drive within the engine and will have a larger negative effect on motor overall performance at lower rpms.
An off-the-shelf motor’s parameters might not be ideally suited to run at a minimal rpm. When an application runs the aforementioned engine at 50 rpm, essentially it is not using all of its available rpm. As the voltage constant (V/Krpm) of the electric motor is set for a higher rpm, the torque continuous (Nm/amp), which can be directly linked to it-is certainly lower than it needs to be. Consequently the application requirements more current to operate a vehicle it than if the application form had a motor specifically designed for 50 rpm.
A gearheads ratio reduces the electric motor rpm, which explains why gearheads are sometimes 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 become 50 rpm. Operating the engine at the higher rpm will allow you to avoid the issues mentioned in bullets 1 and 2. For bullet 3, it enables the design to use less torque and current from the engine based on the mechanical advantage of the gearhead.