Elevator speedometer test elevator speed with what method of detection?

Elevator speed is the rate of change of the elevator z-axis (up and down direction) displacement, caused by the elevator operation control [6], supervision and inspection generally use non-contact (photoelectric) tachometer measurement. The basic principle is the use of reflective photoelectric tachometer sensor, the use of no contact with the object to be measured, in the speed to be measured on the carousel to fix a reflective surface, the black carousel as a non-reflective surface, the two have different reflectivity, when the rotary axis rotation, reflective and non-reflective alternately, photoelectric devices indirectly receive the light reflection signal, converted into an electrical impulse signal. After processing, the speed value can be obtained. Elevator starting and braking acceleration refers to the rate of change of the z-axis speed, caused by the elevator operation control; vibration refers to the change of acceleration value with time when the acceleration value is greater than or less than a reference level appears alternately. The acceleration and its change rate in the process of elevator operation is the main factor affecting the comfort of elevator operation, which is mainly manifested in, firstly, the sense of overweight and weightlessness caused by the change of acceleration in the process of elevator starting and braking, and secondly, the vibration of elevator in the stable speed operation. There are many reasons for elevator vibration, such as low quality of guide rail installation during elevator installation, poor gear meshing of elevator traction machine, improper adjustment of control parameters of frequency converter, inherent vibration frequency of elevator car and vibration frequency of mainframe coincide with the vibration frequency of the elevator to produce *** vibration and so on.