The Composition Principle and Detection of Timer

The Composition Principle and Detection of Timer

Principle: 

The clockwork mechanical timer is composed of a clockwork, a main shaft, and a cam. The mainspring is the power source of the timer. It is made of stainless steel bars of 0.3～0.5mm through a special process. One end of it is fixed on the main shaft, and the other end is connected with the gear. Rotate the knob on the timer by hand to wind up the mainspring, and the wound up after releasing the hand is converted into mechanical energy to drive the gear to rotate. 

After the gear rotates, it will drive the cam to run. When the arc part of the cam is in contact with the reed of the contact, the upper reed is forced to bend downward to close the contact and turn on the power supply of the load; when the notch of the cam is aligned with the contact reed, the upper The reed bounces upwards to separate the contacts, cut off the power supply of the load, and realize timing control.

Detection:

 After rotating the knob on the timer, use the diode block of the digital multimeter to measure the resistance of the contact terminal. The value should alternate between 0 and infinity. If the value is always 0, it means that the contacts are stuck; if the value is always infinity, it means that the timer's contacts cannot be closed.