Linear motor with iron core

Linear motors are often simply described as flattened rotary motors, with the same working principle. The mover (forcer, rotor) is made by compressing coils with epoxy material; the magnetic track fixes magnets (usually high-energy rare-earth magnets) on steel. The motor's mover includes coil windings, Hall element circuit board, thermal regulator (temperature sensor monitors temperature), and electronic interface. In rotary motors, the rotor and stator require rotary bearings to support the rotor to ensure the air gap between the relatively moving parts. Similarly, linear motors require linear guides to maintain the mover's position in the magnetic field generated by the magnetic track. Similar to how encoders in rotary servo motors are mounted on the shaft to provide position feedback, linear motors require a feedback device for linear position feedback - a linear encoder, which can directly measure the load's position to improve the load's position accuracy.

The control of linear motors is the same as that of rotary motors. Like brushless rotary motors, the mover and stator have no mechanical connection (brushless). Unlike rotary motors where the rotor rotates and the stator position remains fixed, the linear motor system can be magnetic track-moving or thrust coil-moving (most positioning system applications have a fixed magnetic track and moving thrust coil). For motors using thrust coil movement, the weight-to-load ratio of the thrust coil is small. However, high-flexibility cables and their management system are required. For motors using magnetic track movement, they must bear not only the load but also the weight of the magnetic track, but no cable management system is needed.
 

TECHNICAL DATA

Peak thrust: 102 - 5875 N
Continuous thrust: 57 - 2800 N
Maximum speed: 4.4 - 36 m/s
Cogging effect reduction technology adopted
High thrust
Good heat dissipation performance
 

NOTE

1. Select the appropriate operating speed. The operating speed of a linear induction motor is related to the synchronous speed, which is proportional to the pole pitch. Therefore, the selection range of the pole pitch determines the selection range of the operating speed. Too small a pole pitch will reduce the slot utilization rate, increase the slot leakage reactance, and reduce the quality factor, thus reducing the motor's efficiency and power factor. The lower limit of the pole pitch is usually 3cm. The pole pitch can be unlimited, but when the motor's output power is constant, the longitudinal length of the primary iron core is limited; at the same time, in order to reduce the longitudinal edge effect, the number of poles of the motor cannot be too small, so the pole pitch cannot be too large.
2. Have appropriate thrust. Rotary motors can adapt to a large thrust range. By matching different gearboxes with rotary motors, different speeds and torques can be obtained. In low-speed situations, the torque can be increased by tens or hundreds of times, so that a very small rotary motor can drive a very large load; of course, power is conserved. Linear induction motors are different; they cannot use gearboxes to change speed and thrust, so their thrust cannot be increased. To obtain a relatively large thrust, one can only rely on increasing the size of the motor. This is sometimes uneconomical. Generally speaking, in industrial applications, linear induction motors are suitable for driving light loads.
3. Have appropriate reciprocating frequency. In industrial applications, linear induction motors are reciprocating. To achieve higher labor productivity, a higher reciprocating frequency is required. This means that the motor must complete its stroke in a shorter time; within one stroke, it must go through the acceleration and deceleration process, that is, it must start and brake once. The higher the reciprocating frequency, the greater the acceleration of the motor, and the greater the thrust corresponding to the acceleration. Sometimes, the thrust corresponding to the acceleration is even greater than the thrust required by the load. The increase in thrust leads to an increase in the size of the motor, and the increase in its mass causes the thrust corresponding to the acceleration to increase further, sometimes resulting in a vicious cycle.
4. Have appropriate positioning accuracy. In many application scenarios, the motor stops moving when it reaches its position due to mechanical limit switches. To reduce impact when reaching the position, mechanical buffer devices can be added. In the absence of mechanical limit switches, a relatively simple positioning method is to control the motor to perform reverse braking or regenerative braking before reaching the position, so that it stops when it reaches the position.