After entering the manual state, manually dial the liquid nitrogen bottle motor gear

The upper limit and the lower limit are two limit switches to ensure that the power supply trigger signal is turned off in time after the liquid nitrogen bottle is in place. The up (down) signal comes from the logic input and is controlled by the microcomputer. The organic combination of these four signals controls the switching and lifting of the liquid nitrogen bottle, thereby ensuring the normal operation of the liquid nitrogen bottle. After entering the manual state, the liquid nitrogen bottle motor gear is manually moved to keep it in the middle position, the lifting action is normal, and the lowering command is invalid. At this time, the upper (lower) level of the side is measured, and the lower limit signal is abnormal, which is a high level (SV), thereby blocking the downward movement of the liquid nitrogen bottle. Check the limit switch: intact; further check and find that the cable from the limit switch to the circuit board is disconnected. After replacing the cable, the fault is eliminated. The liquid nitrogen bottle motor is faulty.
Fault phenomenon The motor is out of control, sometimes not running, and sometimes running in reverse. Troubleshooting Check the motor and related gears and find that the motor is hot and hot so that the hand cannot stay on it. The rated voltage of the motor is 110vAC, and the actual power supply is 220VAC, and the gear part is running for many years, the putty is very thick, causing the motor load to increase and become hot. The treatment scheme is as follows: on one hand, the ash is accumulated, the lubricating oil is added, and the safety chuck is on the other hand, a ZK high-power voltage dividing resistor is arranged on the phase line of the motor. After this treatment, the motor operates normally and the surface is relieved.
Precautions During the handling of this fault, be sure to pay attention to the movement of the motor. After the motor is turned over due to excessive load, its motion is opposite to the logic on the circuit board. It may continue to run after the limit switch is encountered, causing damage to the limit switch or even greater damage. In this maintenance, the motor was reversed and the limit switch carrier was broken. Fortunately, it was found to be timely and did not cause more damage. Fault phenomenon The liquid nitrogen pump motor is operating normally, but liquid nitrogen cannot be extracted. The countermeasures are mostly caused by ice particles blocking on the liquid nitrogen channel, and the ice particles can be removed. Control the humidity of the laboratory to prevent the ice particles in the liquid nitrogen handling container from entering the instrument, which can reduce the occurrence of this failure. The instrument has exceeded its service life and the relevant repair station has been unable to provide the required spare parts, which has brought certain difficulties to the maintenance. This instrument of this hospital is difficult to use with the joint efforts of the operation and maintenance personnel.