However, when the engine inertia is larger than the load inertia, the engine will need more power than is otherwise necessary for the particular application. This boosts costs because it requires paying more for a electric motor that’s bigger than necessary, and because the increased power usage requires higher working 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 measure of an object’s resistance to improve in its movement and is a function of the object’s mass and form. The greater an object’s inertia, the more torque is required to accelerate or decelerate the thing. This implies that when the strain inertia is much bigger than the electric motor inertia, sometimes it can cause excessive overshoot or enhance settling times. Both conditions 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, lightweight materials, and high-energy magnets. This creates higher inertial mismatches between servo motors and the loads they are trying to move. Utilizing a gearhead to better match the inertia of the motor to the inertia of the load allows for using a smaller motor and results in a more responsive system that’s easier to tune. Again, this is attained through the gearhead’s ratio, where in fact the reflected inertia of the load to the engine is decreased by 1/ratio^2.
As servo technology has evolved, with manufacturers producing smaller, yet more powerful motors, servo gearhead gearheads are becoming increasingly essential partners in motion control. Finding the ideal pairing must take into account many engineering considerations.
So how does a gearhead start providing the energy required by today’s more demanding applications? Well, that all goes back again to the fundamentals of gears and their ability to alter the magnitude or direction of an applied drive.
The gears and number of teeth on each gear create a ratio. If a electric motor can generate 20 in-lbs. 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 focus on developing smaller footprints for motors and the gear that they drive, the capability to pair a smaller electric motor with a gearhead to attain the desired torque output is invaluable.
A motor may 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 working at a very low acceleration, such as for example 50 rpm, as well as your motor feedback quality is not high enough, the update rate of the electronic drive may cause a velocity ripple in the application. For example, 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 using to control the motor has a velocity loop of 0.125 milliseconds, it’ll look for that measurable count at every 0.0375 amount of shaft rotation at 50 rpm (300 deg/sec). When it does not find that count it’ll speed up the motor rotation to find it. At the swiftness that it finds the next measurable count the rpm will become too fast for the application form and the drive will sluggish the engine rpm back down to 50 rpm and then the complete process starts yet again. This continuous increase and decrease in rpm is what will cause 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 motor during operation. The eddy currents actually produce a drag power within the electric motor and will have a greater negative effect on motor performance at lower rpms.
An off-the-shelf motor’s parameters might not be ideally suitable for run at a low rpm. When an application runs the aforementioned engine at 50 rpm, essentially it is not using most of its offered rpm. Because the voltage constant (V/Krpm) of the electric motor is set for an increased rpm, the torque continuous (Nm/amp), which is certainly directly related to it-is usually lower than it requires to be. Consequently the application requirements more current to operate a vehicle it than if the application form had a motor particularly designed for 50 rpm.
A gearheads ratio reduces the engine rpm, which explains why gearheads are sometimes called gear reducers. Using a gearhead with a 40:1 ratio, the engine rpm at the insight of the gearhead will end up being 2,000 rpm and the rpm at the result of the gearhead will become 50 rpm. Operating the engine at the higher rpm will permit you to prevent the worries mentioned in bullets 1 and 2. For bullet 3, it allows the look to use much less torque and current from the electric motor predicated on the mechanical benefit of the gearhead.