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Shanghai Ouqin Electromechanical Engineering Technology Co., Ltd
Briefly describe the common faults and corresponding solutions of Dold relays
Date: 2025-10-23Read: 22
Doll relays are mainly used to monitor safety circuits such as emergency stop buttons, safety doors, light curtains, and dual hand controls. Once a danger signal is detected, the power supply can be immediately cut off to achieve safe shutdown. Its reliability is directly related to production safety. However, in complex electromagnetic environments and long-term operation, Dold relays may experience issues such as misoperation, failure to operate, or self check failure. Mastering the solutions to common faults is the key to building a solid safety bottom line.
Problem 1: The safety circuit is normal, but the relay is not engaged
First, check if the power supply voltage is within the rated range (such as 24VDC) and if the polarity is reversed. Confirm whether the safety input signal (such as the normally closed contact of the emergency stop button) is conducting, and use a multimeter to measure the circuit continuity. If it is a dual channel input, check whether the two signals are synchronized to avoid self-test failure due to timing deviation. Some models require manual reset after power on, confirm that the reset button has been pressed.
Problem 2: Frequent misoperation or tripping
Mostly caused by poor contact or interference in safety circuits. Focus on checking whether the emergency stop button, safety door lock and other contacts are oxidized, loose or damp. Check if the circuit has been compressed or worn, causing intermittent open circuits. If there is strong electromagnetic interference in the environment, shielded cables should be used and the shielding layer should be grounded at one end. Avoid laying safety circuits parallel to power lines.
Problem 3: Test function failure or abnormal indicator light
Usually equipped with LED status indication and manual testing button. If there is no response during testing, check if the test circuit is connected correctly. If all indicator lights are off, it may be a power failure; If the red light is constantly on, it indicates that the safety circuit is disconnected or the internal self-test has failed. Refer to the product manual and determine the specific type of fault based on the flashing code.
Problem 4: The output contacts do not move or are stuck
Use a multimeter to check if the on/off status of the output terminal is normal in a safe state. If the contact is stuck (unable to disconnect), it indicates that it has been damaged and must be replaced immediately. Continued use is strictly prohibited. It is strictly prohibited to connect loads exceeding the rated current at the output end to prevent arc erosion of the contacts.
Question 5: Self checking function alarm
Modern products have dual channel redundancy and cross monitoring functions. If the self-test finds that the two channels are not synchronized, there is a logic error, or there is an internal component failure, it will automatically lock and alarm. At this point, a system check is required to confirm that all safety devices (such as light curtains and door locks) are working properly; Check if the wiring diagram meets the manufacturer's requirements; Replace the relay if necessary.