1。 The control system of motor is composed of switch, small transformer, fuse, main and auxiliary contactor, relay, temperature and pressure induction device, etc。 It is relatively complex。 There are many kinds of faults, so it is often necessary to analyze and check them by means of control schematic diagram。 At ordinary times, we should pay attention to keeping the inside and outside of the control box clean and dry。 There should be no water or oil pollution。 We should regularly use a small sweeper to blow out the dust on the components and wiring posts of the box, or dip the brush in the electrical cleaner to clean it, so as to avoid affecting the work or insulation of contactors and relays。 There is a control box with moisture resistance, generally do not turn off the heating switch at will。 The grounding reliability of the box body should also be maintained to prevent electric shock。 When replacing the relay contactor, attention should be paid to the working voltage of the electromagnetic coil, so as to avoid burning the coil by mistake。 Generally, there are 24V, 110V and 220V。 For time relay, besides the coil voltage requirement, the time regulation unit (time, minute, second) and range of time relay should be clarified。
2。 Star-triangle (Y-Delta) method is used to start (conversion delay is about 5 seconds) motors, to see whether the conversion start-up is normal。 Usually, the manufacturer has strict regulations on the start-up cycle of the motor (i。e。 the number of start-up times per minute)。 It will have warning labels on the start-up control box to remind users to prevent the motor from being damaged by frequent start-up。 At the same time, it will also prevent some electrical components in the start-up control box (such as starting reactor) from burning out。 Therefore, for the motor control system with frequent start-stop or large current, the inspection and maintenance period should be shortened。 For example: Keling, anchor, winch, main auxiliary blower, main air compressor and boiler water pump should be paid close attention to, and the protection function of thermal overload relay should be checked regularly (small red mark color system can be moved next to it)。 Its setting action value should not exceed the rated current value of motor nameplate to ensure that it can play the role of overload protection。
3. Inspect wiring and screw tightening regularly to prevent wiring and screw loosening. Check whether the switch, contactor, relay and other components are damaged or ablated, and whether the working status of each component and the functions of start, stop and interlock are normal. It is necessary to keep the contactor's dynamic and static contacts in good contact, so as to avoid burning due to the lack of phase operation of the motor due to poor contact between contacts. If the contact surface is good, only blackened, can be rubbed with coarse cloth, do not easily polish the surface of the heat-resistant alloy layer, otherwise it will shorten the life of the contact; if the surface of the contact is seriously ablated, it can be rubbed flat with "0" sandpaper. Dynamic and static contacts should be kept in line or surface contact, not point contact. Contact condition can be checked by placing a strip of paper between the static and dynamic contacts. If it is not clamped tightly during suction, it indicates that the contacts or springs need to be adjusted or renewed.
In a word, as long as the mechanics and electricians strengthen their sense of responsibility, carry out periodic motor inspection, motor maintenance and motor maintenance according to the requirements, and when the sound, temperature rise, working current and insulation of the equipment are found to be abnormal, and can be handled in time, our electrical management level will surely go up to a new level for the operation of the fleet。 Add a security guarantee。