Magnetic clutch in the elevator control system application on
|
| 发布时间：2010.04.29 新闻来源：Zhejiang Huiyue Bearing technology Co., Ltd. 浏览次数： |
| |
With the development of urban construction on the high-rise building elevator motor control system have become increasingly demanding. Both the requirements of good comfort, flat layer of high accuracy, and need to speed performance, and speed range. Commonly used in variable speed motors with AC motors and DC motors. AC motors, compact structure, easy maintenance, lower prices, but poor comfort, usually with lifts, and the narrow speed range, the control of the elevator speed of 1 m / sec. DC motor with speed performance, the characteristics of speed range, control of the elevator speed of 4 m / s, but the unit structure, bulky, power and more and more maintenance work, high cost, mainly for the rated speed of the elevator 2 m / s or 2 m / s or more types of elevators. In 1984, the first swing with the frequency (VVVF) system control the elevator came, the speed control up to 6 m / s, small size, light weight, high efficiency + save energy, but very expensive by the speed range frequency change, speed can not be from 0 - rated speed + seen from a practical application, but also easy to cause trouble. To this end, we work under the magnetic characteristics of the clutch, which is used in the + elevator motor control system AC motor drives, DC motor speed control to achieve results, and the small size, light weight, economical and suitable properties.
Design and Control Principle 1
Elevator control system is designed kinematic diagram shown in Figure l. The structure of the main motor, magnetic clutch, speed change mechanism, reel, pulley blocks and other components. Elevator speed control system with other comparison, the difference is that the ordinary AC motor drives, magnetic clutch in speed.
For AC motors, speed formula for n = 60f1 * (1 a s) / P (f1 frequency of a power pole on the number of s p a slip), even if the power to change the frequency of the stator, the motor can smoothly change synchronous speed. In many cases, the need to maintain speed when the maximum torque unchanged. Week motor torque m = k2 (u1/f1 (k2 is a constant, u1 is the stator winding voltage, f1 power supply to the stator frequency). To ensure the electromagnetic torque is constant, that is, u1 value, then change the power zygomatic rate, requested the supply voltage should be adjusted accordingly.
Schematic diagram of magnetic clutch shown in Figure 2, where a metal outer cylinder, 2 powder. Excitation coil 3 and 4 for the electromagnetic rotor. 5, the conductive ring. Between 1 and 4, a small amount of space left, usually 1.5-2mm, built a very small wear spherical magnetic shake powder, when the excitation coil no current consultations, the bulk copy-like powder does not obstruct the main follower Cambodia movement between the fins on the clutch state of separation; when Walter current, magnetic powder that is attracted in the magnetic field is magnetized together and form a chain along the air gap magnetic solid, through its combination of power, the master slave cases linked to the clutch is engaged.
Speed in the magnetic powder clutch system, shown in Figure 3, magnetic clutch torque change and a linear relationship between the excitation current, so you can power through the brush, adjust excitation current to accurately control the torque size, response time, and can show good reproducibility. Moreover, seen from Figure 4, the output torque corresponds to a current value, and has nothing to do with the speed, by adjusting the excitation current value, both to maintain constant torque output, but also free to change the torque value, resulting in a wider the speed range, when using pure iron made very little remanence magnetic clutch, the speed can range from zero to rated torque.
2 magnetic clutch control system the main technical parameters and characteristics
Frequency adjustment is to 3.7kw four-speed motor, for example, magnetic clutch compared motor control system the main technical parameters are as follows
From the above results, the magnetic system from the tuner to adjust the motor speed range, the structure is simple, safe, reliable, rapid response, small size, light weight and low price. And the torque value corresponding to a current i and repeat the performance, can realize the torque control, motor output is load, can accurately control the speed.
|
| |
|
