During the operation of the hydraulic oil pump motor, the motor sometimes stops, sometimes starts, and starts for a few minutes. It will stop and stop for a while, and then start again. The speed is still very slow. What is the reason? Dalan Motor will shove the cause and effect of the problem.
After a while, the work stopped. If this kind of fault is not discovered and processed in time, it will be easy to burn out the motor and the components of the control system for a long time.
Failure principle analysis: If we understand the characteristics of thermal relays, we can understand the causes of such failures. Thermal relay is a relay that uses the thermal effect of current to protect the motor from long-term overload.
When we set the thermal relay to an automatic reset mode, when the load carried by the contactor works under overload conditions for a long time, the thermal relay can disconnect the power supply of the contactor package within the effective time to protect the motor. However, after the self-locking mechanism in the thermal relay cools, the control switch in the thermal relay sends power to the contactor to drive the motor to work. At this time, the system returns to normal, but within a few minutes, the thermal relay re-heats and disconnects. The motor of the contactor is stopped again.
Cause analysis and treatment method of the fault: Introduction to motor repair. From the above analysis, we know that the cause of the fault is the thermal relay, so what is the cause of the protective action of the thermal relay? We know that the lack of phase or partial phase of the load (the voltage of a certain phase is very low) is the main reason for the action of the thermal relay.
Judgment method adopts direct detection method, turn off the machine, measure and judge each device according to the principle from back to front, from the motor all the way to the user's power knife fuse, it will cause the lack of phase or poor contact control device replacement or Tighten.
The following points are several situations that often occur in actual maintenance:
(1) The connection between the thermal relay and the contactor is poor;
(2) The contact of the AC contactor is oxidized, the contact is bad or the contact is burnt out;
(3) The connection wires of each device are poorly connected, especially the wiring of the power switch and the motor itself;
(4) Poor contact of user's gate knife fuse or loose connection of incoming terminal;
(5) The current of the thermal relay protection is adjusted too low. In particular, pay attention to the setting current of the thermal relay should be appropriately increased in summer, generally 4.5-5 amperes
(6) The thermal relay has been used for too long, and the internal control locking mechanism itself has deteriorated.
----- Responsible Editor: Dalan Oil Pump Motor 02-Procurement Consultant
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