When the JKM pulls in, the current flows through the motor rotor DM on one hand, and on the other hand through the door opening resistance RKM, from M2→M3, the door machine rotates to the door opening direction, because the RKM resistance value is large at this time, and the shunt through RKM is small. Therefore, the door opens faster. As the elevator door is closed to 3/4 stroke, the switch deceleration limit 1KM is turned on, and most of the resistance of RKM is short-circuited, contributing to the increase of the shunt through RKM. In doing so, the motor speed reduces, which helps the deceleration of door opening. When the opening ends, the door opening interruption limit is cut off, the opening relay is released, and the elevator stops opening the door.
When the JGM pulls in, the current flows through DM on one hand, and on the other hand, through the closing resistance RGM, from M3→M2, the elevator door machine rotates in the closing direction. Because the resistance value of RGM is larger at this time, the shunt through RGM is smaller, so the door closing speed is faster. When the elevator is closed to half of the trip, the door-closing first-stage deceleration limit JGM is turned on, and a part of the resistance of the RGM is short-circuited so that the shunt from RGM is increased, and the door machine realizes the first-stage deceleration. When the elevator continues to close to the 3/4 stroke, the connection to the secondary deceleration limit 2GM and short-circuit most of the RGM resistors help the further increase of the shunt from RGM, and the elevator door speed is further reduced, realizing the secondary deceleration of door closing. When the door is closed, the door closing terminal limit is cut off, the door closing relay is released, and the elevator stops closing the door. By adjusting the total voltage divider resistance RMD in the switch gate circuit, the total speed of the switch gate can be controlled.
Because when JY pulls in, the magnetic winding DMO in the elevator door machine always has electricity, so when JKM or JGM is released, the motor can immediately enter the energy consumption braking, and the door machine stops immediately. Moreover, when the elevator door is closed, a braking force can be provided to ensure that the elevator door cannot be easily opened in the car.
Most of the elevators produced now use the VVVF variable frequency door operator system. As for the general variable frequency door operator system, the control panel provides the door operator system with a power source, a door opening signal and a door closing signal.
The variable frequency door operator system also has a deceleration switch and a terminal switch, most of which use a bistable magnetic switch. The door machine system has a self-learning function. When the door operator terminal switch is activated, it will return to the control screen for a terminal signal to control the door switch relay.
Generally, the variable frequency door operator can set the door opening and closing speed, torque, deceleration point position, etc. For details, please refer to the door operator system manual provided by the manufacturer or elevator debugging data for adjustment.
Some variable frequency door machines lose the signal of the open position after the car door is pulled after power failure. The door machine will no longer be controlled by the door open/close signal of the control panel, and it must be self-learning once the power is off before it can work normally.
In addition to being controlled by the door opening and closing signal of the control panel, some variable frequency door operator systems have their force limit calculation function. When the force limit exceeds the set value during door closing, it will open in the opposite direction. This force limit calculation becomes invalid after reaching the closing terminal switch action. For this kind of door system, the position of the door closing terminal must be ahead of the car door lock, otherwise, the elevator can run after the door lock is turned on. If this force limit calculation is still valid, it may give rise to the elevator opening the door during operation, which should be paid attention to.
This section is an advanced version, suitable for heavy-lift cargo elevators, to ensure normal operation under heavy loads.