Detection method for malfunction of the electric telescopic door (i.e., inability to open or close)

The editor has summarized some detection methods for the situation where the electric telescopic door cannot be opened or closed. We hope these will be of some help to you in your daily use of the electric telescopic door. 

First, check if there is mains power and if the circuit breaker is damaged. If the fuse has blown, a thorough inspection must be conducted. 

2. Remove the plug of the underground cable from the communication room, and use the Rx1 setting on the multimeter to measure whether the three leads (red, white, and yellow) of the motor are connected (the resistance should be around 15 ohms for the yellow (red) and white, and around 30 ohms for the yellow and red). Then, use the R×10K setting to measure whether there is a certain resistance between these lines and other lines (mainly to check if there is an indirect short circuit between the wires). The three motor wires are not connected (the resistance is infinity), then check the red, white, and yellow wires in the tail connection box of the machine. If they are connected, it indicates that the red, white, and yellow wires in the underground cable are disconnected; if they are not connected: then remove the machine cover, and measure these three wires at the plug where the door row is connected to the machine head again. If they are connected, it indicates that the line from the door row to the communication room is broken (including any poor contact of the plugs); if they are still not connected, directly measure whether the motor stator coil is broken. 

3. The power lines of the telescopic door motor are only connected between red and yellow, and not connected with white. Check if the motor stator is overheating. If it is overheated severely, it indicates that the motor has stopped due to thermal protection and cannot be switched on or off. (The luxury non-railway door only has red and yellow connected, because an electronic soft-start device is connected to the white line with a thyristor. If the thyristor is open-circuited, it will take several seconds before starting.) If it is not overheated, check if the 20UF starting capacitor has failed. 

4. If the motor still fails to switch on or off, then measure whether the three limit signal lines (blue, green, and gray) are short-circuited. The automatic stop of the door when it reaches the position is controlled by the limit sensors K1 and K2. If both sensors K1 and K2 are short-circuited simultaneously, it is equivalent to the door being limited both when opening and closing, resulting in the inability to switch on or off. 

5. The motor wires and signal wires are in good condition, but the switch still doesn't work. This indicates that there is a fault in the control box. If there is any short circuit somewhere, the newly replaced part might get damaged again. Therefore, we need to thoroughly inspect each part. Only after eliminating other potential faults can we proceed with the replacement.