Some daily maintenance precautions for Sima motor maintenanceSima motor maintenance information: the motor control system consists of switches, fuses, main and auxiliary contactors, relays, temperature, induction devices, etc. This is relatively complex. There are many kinds of faults, which usually need to be analyzed and checked by the control schematic diagram.
At ordinary times, the control box should be kept clean and dry, without water stains. Use a small fan to blow the dust on the junction box and terminal block regularly (every week), or use a brush dipped with electric cleaner to avoid affecting the operation or insulation of the contactor and relay. The control box is equipped with moisture drying resistance, generally do not turn off the heating switch at will. In order to prevent electric shock, the box must also be reliably grounded.
The fastening of wires and screws in the junction box shall be checked regularly (monthly) to prevent loosening of wires and screws. Check whether the switch, contactor, relay and other components are damaged or burnt, and whether the working state of each component, start, stop and interlocking functions are normal. In order to keep the contactor moving, the fixed contact suction and good contact, avoid the motor burning due to the lack of phase operation caused by poor contact. If the contact surface is good and only black, it can be wiped with a coarse cloth. The surface heat-resistant alloy layer should not be easily polished off, otherwise the contact life will be shortened. If the contact surface is seriously ablated, it can be polished with "0" sandpaper. The movable and static contacts shall maintain line contact or surface contact instead of point contact. Contact conditions can be checked by placing a sheet of paper between movable, static contacts. If the clamp is not tight during suction, adjust or replace the contact or spring. This needs attention. In the lighter case, due to the poor contact, there will be a large contact resistance (current), which means that the load will increase, causing the overload protection relay to trip. In the heavy case, the motor will burn down due to the lack of phase operation.
When replacing relays and contactors, Sima motor must pay attention to the working voltage of the electromagnetic coil to avoid misfiring the coil. Generally, there are 24V, 220V and 380V. For time relay, in addition to the coil voltage requirements, the time regulating unit (time, minute, second) and the range of time relay shall also be specified. Whether the setting current of thermal relay is reasonable and appropriate. For motors started by the star delta (Y - △) method (conversion delay is about 5 seconds), check whether the conversion start is normal. Generally speaking, the manufacturer has strict regulations on the starting cycle of the motor (i.e. the starting time per minute), and will stick a warning label on the starting control box to remind the user to prevent the motor from being damaged due to frequent starting, and prevent some electrical components (such as starting reactor, etc.). ）Start with heating and burning. Therefore, for the motor control system with frequent start and stop or high current, the inspection and maintenance cycle should be shortened. Regularly check the protection function of thermal overload relay (the red system beside can be switched), and its set action value shall not exceed the rated current value of motor nameplate to ensure overload protection.