However, when the electric motor inertia is bigger than the load inertia, the motor will need more power than is otherwise essential for the particular 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 complement the inertia of the motor to the inertia of the strain.
Recall that inertia is a way of measuring an object’s resistance to improve in its movement 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 thing. This means that when the load inertia is much larger than the motor inertia, sometimes it could cause excessive overshoot or increase settling times. Both circumstances can decrease production collection throughput.
Inertia Matching: Today’s servo motors are generating more torque relative to frame size. That’s because of dense copper windings, light-weight materials, and high-energy magnets. This creates higher inertial mismatches between servo motors and the loads they are trying to move. Using a gearhead to raised match the inertia of the motor to the inertia of the strain allows for using a smaller motor and outcomes in a far more responsive system that’s easier to tune. Again, this is achieved through the gearhead’s ratio, where in fact the reflected inertia of the load to the precision gearbox engine is decreased by 1/ratio^2.
As servo technology has evolved, with manufacturers creating smaller, yet more powerful motors, gearheads are becoming increasingly essential partners in motion control. Finding the optimal 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 all goes back again to the basics of gears and their ability to change 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-pounds. of torque, and a 10:1 ratio gearhead is attached to its output, the resulting torque will be close to 200 in-lbs. With the ongoing emphasis on developing smaller footprints for motors and the gear that they drive, the ability 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 just require 50 rpm. Trying to perform the motor at 50 rpm may not be optimal predicated on the following;
If you are working at a very low velocity, such as 50 rpm, and your motor feedback resolution 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 just one 1,000 counts/rev you have a measurable count at every 0.357 degree of shaft rotation. If the digital 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 does not discover that count it’ll speed up the electric motor rotation to think it is. At the velocity that it finds the next measurable count the rpm will become too fast for the application and the drive will slow the motor rpm back down to 50 rpm and the whole process starts all over again. This constant increase and decrease in rpm is exactly what will cause velocity ripple within an application.
A servo motor running at low rpm operates inefficiently. Eddy currents are loops of electric current that are induced within the engine during operation. The eddy currents actually produce a drag power within the motor and will have a greater negative effect on motor functionality at lower rpms.
An off-the-shelf motor’s parameters may not be ideally suitable for run at a low rpm. When an application runs the aforementioned engine at 50 rpm, essentially it isn’t using most of its obtainable rpm. Because the voltage constant (V/Krpm) of the motor is set for a higher rpm, the torque continuous (Nm/amp), which is usually directly related to it-is usually lower than it requires to be. Because of this the application needs more current to operate a vehicle it than if the application form had a motor particularly made for 50 rpm.
A gearheads ratio reduces the electric motor rpm, which is why gearheads are occasionally called gear reducers. Using a gearhead with a 40:1 ratio, the electric motor rpm at the insight of the gearhead will become 2,000 rpm and the rpm at the output of the gearhead will end up being 50 rpm. Working the engine at the bigger rpm will allow you to avoid the problems mentioned in bullets 1 and 2. For bullet 3, it enables the look to use much less torque and current from the electric motor predicated on the mechanical advantage of the gearhead.