Protecting sensitive equipment from harmful vibrations can be done with either passive or active isolation systems, with the choice often being made on price, simplicity, and the level of protection required. Although passive systems are typically simpler and lower cost, most passive designs can’t protect against the low-frequency vibrations caused by structural resonances. And active […]
Vibration damping: What’s the difference between passive and active methods?
Unlike typical static or dynamic loads, forces due to vibrations are difficult to predict, model, and account for when designing motion control systems. Some manufacturers recommend adding a safety factor to account for vibrations when sizing and selecting components — especially those that involve rolling or sliding motion, such as linear guides and screws. Of […]
When to use gears to change the inertia ratio of a motor-driven system
In any system where a motor drives a load to achieve precise positioning, velocity, or torque, the ratio of the load inertia to the motor inertia plays a significant role in determining the motor’s ability to effectively and efficiently control the load, especially during acceleration and deceleration portions of the motion profile. In this context, the […]
What is disturbance rejection in motion control?
One of the key functions of a motion controller is to create the trajectories the motor follows in order to reach the target position (or velocity or torque). As the motor turns, the controller processes feedback from the encoder and compares the actual position of the motor with the desired position. If there are any […]
AC induction motor inertia: What’s the difference between WK2 and WR2?
In any motor-driven system, the difference between the motor inertia and the load inertia will affect the system’s performance — especially its ability to accelerate the load quickly and efficiently. While servo motors are the preferred choice for applications that specify a precise move profile, AC induction motors are often the better choice for applications […]
What is droop control in the context of AC motors and drives?
One of the fundamental characteristics of an AC induction motor is that the rotor spins at a slower rate than that of the stator’s rotating magnetic field. This difference in speed between the rotor and the stator’s magnetic field is known as slip. Slip allows the motor to produce torque — the higher the slip, […]
What’s the difference between a dashpot and a snubber?
Dashpots and snubbers are two types of pneumatic device used for controlling the movement of a load — typically for the purpose of controlled deceleration or motion damping. Although they can be used to control rotary motion, the more common uses for dashpots and snubbers in industrial applications involve the control of linear motion mechanisms, […]
What’s the difference between PL and SIL machine safety standards?
Machine safety is governed by two standards: EN/ISO 13849-1 and EN/IEC 62061. Both standards are harmonized to the EU Machinery Directive 2006/42/EC, which defines the Essential Health and Safety Requirements (EHSR) for machinery. Although their methods for performing risk assessment are different, both standards — EN ISO 13849-1 and EN 62061 — when correctly applied, […]
Encoder Products absolute encoders – now with improved electronics
EPC’s line of absolute encoders offers magnetic multi-turn technology and higher resolution. Encoder Products Company (EPC) offers a full line of absolute encoders with models in both shaft and blind hollow bore, in sizes 36 mm, 58 mm, and standard size 25 with a 2.5 inch housing. Now, EPC absolute encoders come with even more […]
What features make resolvers suitable for harsh environments?
Resolvers were initially developed for military applications and are probably best known as the preferred feedback solution in harsh environments. Where optical or magnetic encoders are sensitive to dust, liquids, and magnetic fields, resolvers can operate in dirty, humid, wet, and high-radiation environments. But what is it that makes them so robust under conditions that […]