Safety component switch of elevator safety circuit

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Elevator safety circuit:

3、 Safety component switches for elevator safety circuits:

1. Speed limiter switch (including speed limiter rope breaking switch) - a safety device that can activate the safety clamp when the elevator's speed exceeds a certain value of the rated speed (at least 115% of the rated speed).

2. Maintenance switches - divided into control cabinet maintenance switches, car interior maintenance switches, and car roof maintenance switches. Three maintenance switches are interlocked to prevent misoperation and ensure the safety of maintenance personnel.

3. Bottom buffer switch - This device is located at the bottom of the shaft and is set at the bottom limit position of the car and counterweight travel. The switch device used to check the normal reset of the buffer, which is an elastic buffer safety device used to absorb the kinetic energy of the car and counterweight. The elevator can only operate normally after the buffer returns to its normal extended position.

4. Upper and lower limit interlocking switch - a non automatic reset safety device that forcibly cuts off the main power supply and control power supply before the car or counterweight touches the buffer when the car exceeds the level magnetic induction device during operation. The device is set in a position that works as close as possible to the end station without any risk of misoperation. It should take effect before the car or counterweight (if any) comes into contact with the buffer, and maintain its operating state during the compression of the buffer. For elevators with forced drive, the function of the limit switch is to directly cut off the power supply circuit of the motor and brake. After the limit switch is activated, the elevator cannot automatically resume operation.

5. Safety clamp switch - check if the speed limiter is activated. If the speed limiter is activated, it stops the car or counterweight from running and maintains a stationary state, and can clamp the mechanical safety device on the guide rail.

6. Safety window switch - refers to a manually locked safety device installed on the safety window of the elevator car. If the lock fails, the device can stop the elevator. Only after re locking can the elevator resume operation.

7. Hall door and car door interlocking switch - a mechanical and electrical interlocking safety device that locks the hall door and car door after they are closed, and at the same time connects the control circuit, allowing the car to operate. Its function is that when the elevator car stops at a certain floor, the hall doors of other floors are effectively locked. If the elevator is opened, it cannot start or maintain normal operation.

8. Handwheel switch (optional) - When the elevator malfunctions and the car stops between two levels, cutting off the handwheel switch, releasing the safety gear, and turning the handwheel can bring the car to the nearest level.

9. Overspeed protection switch (optional) - capable of detecting the loss of control of the speed of the ascending car and stopping the car, or at least reducing its speed to the design range of the counterweight buffer. 4、 Function of safety circuit

To ensure the safe operation of the elevator, many safety components are installed on the elevator. The elevator can only operate when every safety component is in normal condition, otherwise the elevator will immediately stop running. The so-called safety circuit refers to the installation of a safety switch in each safety component of the elevator, connecting all safety switches in series to control a safety relay. Only when all safety switches are turned on and the safety relay is engaged, can the elevator be powered on and run. Common safety circuit switches include: machine room: control screen emergency stop switch, phase sequence relay, thermal relay, speed limiter switch; shaft: upper limit switch, lower limit switch (some elevators place these two switches in the safety circuit, while others use these two switches to directly control the power supply); pit: rope break protection switch, pit maintenance box emergency stop switch, buffer switch; car interior: control box emergency stop switch; car roof: safety window switch, safety clamp switch, car roof maintenance box emergency stop switch; fault status: when the elevator is in a stopped state, all signals cannot be registered, and both fast and slow trains cannot run. The first suspicion is a safety circuit fault. You should go to the control screen in the computer room to observe the status of the safety relay. If the safety relay is in the released state, it should be judged as a safety circuit fault. Possible causes of malfunction: 1 The phase sequence of the input power supply is incorrect or there is a missing phase, causing the phase sequence relay to operate. two The elevator has been operating at overload or stuck for a long time, causing the thermal relay to activate. three Possible overspeed of the speed limiter may cause the speed limiter switch to operate. four The limit switch action is caused by the elevator hitting the top or sinking to the bottom. five The pit rope switch is activated. It may be due to the speed limiter rope jumping out or being too long. six Safety clamp action. The cause should be identified. It may be due to overspeed action of the speed limiter, misoperation of the speed limiter due to oil loss, oil loss of the pit pulley, foreign objects (such as mice) being caught in the pit pulley, or too small a gap between the safety blocks. seven The safety window was lifted by someone, causing the safety window switch to operate. eight Some emergency stop switches may have been pressed by someone. nine If all switches are normal, check whether their contacts are in good contact and whether the wiring is loose. In addition, although the safety circuit of many elevators is normal and the safety relay is also closed, a normally open contact is usually taken from the safety relay and sent to a microcomputer (or PC) for testing. If the safety relay itself has poor contact, it can also cause a fault in the safety circuit.