The Function and Working Principle of Safety Relay

The function and working principle of safety relay

The so-called "safety relay" is not a "fault-free relay". It has a forced guide contact structure to ensure safety in the event of contact welding. This is completely different from ordinary relays. .

Safety relays are used in the design of safety circuits that have an input to confirm the safety of the machine. After confirming safety, the input to the contactor etc. is controlled.

The function of safety relay:

1. Before the emergency stop is lifted, the machine cannot restart suddenly.

2. When the machine safety circuit fails, the machine power supply can be stopped.

3. If the safety circuit fails, the machine cannot be started again.

working principle:

Safety relays are composed of several relays and circuits in order to complement each other's abnormal defects and achieve complete relay functions with correct and low malfunctions. The lower the error and failure values, the higher the safety factor. Therefore, a variety of safety relays need to be designed to protect different levels of machinery.

Safety relays can be divided into electromagnetic safety relays, thermal reed relays and solid-state relays; the working principles of safety relays can also be roughly divided into three types

1. Safety relays are composed of several relays and circuits in order to complement each other's abnormal defects and achieve complete relay functions with correct and low malfunctions. The lower the error and failure values, the better the safety factor. High, so a variety of safety relays need to be designed to protect different levels of machinery. The reason for use is to protect machine operators exposed to different levels of hazards.

2. A relay with safety protection function

Low-voltage control of high-voltage is also called four ounces of pulling a thousand pounds. For human safety, avoid the danger of arcing when directly contacting the high-voltage switch. Relays that use low-voltage electrical switches to control high-voltage electrical switches. To put it bluntly, the magnetic core of low-voltage electricity attracts the switch of high-voltage electricity.

3. The so-called "safety relay" is not a "fault-free relay". It has a forced guide contact structure, which can ensure safety in the event of contact welding. Where are safety relays used? (1) In emergencies When the stop is released, the machine cannot restart suddenly (2). In case the machine safety circuit fails, the machine power supply can be stopped (3). When the safety circuit fails, the machine cannot restart. Check with safety switches, light curtains, etc. Safe input cannot perform the above functions.

HZJB-I 3 Phase Relay Protection Tester