What is the switch 2

 AC fan cooling motor fan cover 
Specifications
1. Customised
2. good quality
3. Surface treatment: Galvanize
4. Type: Motor Cover 
Until 1938, invented the crossbar (cross bar) switches to solve the above problems, relative to the step by step system switches, important improvements it has two aspects: 1. The use of the contact pressure relay control connection array instead of the big action step by step, thus reducing the wear and noise, improve the reliability and the connection speed; 2. The transition from direct control to indirect control method, so that users dial pulse is not directly control switch action, and the first received by register, electric fan motor storage, and then through the marker drive connector, indirect continue to complete the users. This way of indirect control separate control part way with words, to increase the control efficiency, flexibility and picked up speed. 


Totally Enclosed Protect Feature and Three-phase Phase low rpm ac electric motor

Specifications
power range: 0.12-18.5 kW 
Centre height of frame: 63-160 mm 
Rated Voltage: 380 V 

Rated Frequency: 50Hz or 60Hz 
Because the crossbar switch has a series of advantages, so it occupies an important position in the development of the telephone exchange, has been widely used, until now, quite a number of magnet generator countries in the world and the public telephone network is still in the minority areas of China and use the switches With the birth of the semiconductor devices and computer technology and the rapid development of violently hitting the traditional electromechanical exchange structure, make it to the electronic. Bell companies in the United States after the hard work in 1965, produced the world's first commercial stored Three phase motor program control electronic switch (No. 1 ESS), which marks the telephone switches from the mechanical age into electronic age, making exchange technology in the era of change. Because the electronic switch has small volume, quick speed, easy to provide efficient and reliable service, etc, caused great interest from all over the world. In the process of development have developed various types of electronic switches.