Motor check wiring
Whether it is an AC motor or a DC motor, the windings are generally separated, and the windings are connected according to certain requirements and connected to the external circuit, which is called the wiring of the motor. The wiring of the motor is a very important task in the motor installation. Before wiring, you should understand the wiring diagram of the design drawing. When wiring, you can wire according to the wiring diagram in the motor junction box. The wiring methods vary.
The wiring of the DC motor is usually indicated on the cover of the junction box with a circuit diagram, which can be selected according to the excitation form and load steering requirements. Except that the dragged load has strict requirements on steering, the wiring of the AC motor will only reverse the motor without damaging the motor even if the phases are reversed. However, if the excitation winding and the armature winding of the DC motor are indirectly opposite each other, the motor armature may be charged, and the field winding may be de-energized without being charged, so that the motor may fly when it is no-load, and the rotor may be burnt when it is heavy. Therefore, the external wiring of the armature winding and the field winding of the DC motor must not be indirectly indirect with each other. External wiring of the motor. Before connecting the motor to the external wire, check whether the winding terminals of the end cap are loose. When the crimping screw of the internal lead wire is tightened, the shorting piece can be connected according to the required wiring method, and the external wire can be crimped. Before the motor is connected, check the insulation of the motor. It is best to complete the unit debugging of the motor before wiring. When the motor meets the requirements of the current specification, connect the external line. Generally, the insulation resistance of low-voltage motors is required to be greater than 0.5MΩ, and the shaking table is used at 500V. After the motor is installed and wired, the following checks should be carried out before the motor is commissioned:
(1) The civil engineering cleaning and finishing is completed;
(2) The motor is installed and the inspection is completed;
(3) The debugging of the secondary circuit such as the motor control circuit is completed and the work is normal;
(4) When moving the rotor of the motor, the rotation is flexible and there is no chucking phenomenon;
(5) All wiring of the main circuit of the motor is firmly fixed without any looseness;
(6) Other affiliated systems are fully qualified. Among the above six items, the installation electrician should pay special attention to the fifth article. The main circuit system described here refers to all the main circuit wirings from the power supply input of the power distribution cabinet to the motor terminal, and must be firmly connected. That is, each knife switch, air switch, contactor, fuse and thermal relay, the upper and lower contacts of the terminal block of the power distribution cabinet and the motor wiring must be firmly connected to ensure reliable and safe operation of the motor. Otherwise, there will be burning. The danger of a bad motor. When the motor is in trial operation, it is necessary to monitor whether the current of the motor exceeds the specified value and record it. In addition, the following items should also be checked:
(1) Whether the direction of rotation of the motor meets the requirements. When the AC motor is reversed, the two motors can be exchanged arbitrarily; when the DC motor is reversed, the two armature voltage wirings can be exchanged, and the two excitation voltage wirings can also be changed.
(2) The sound of the motor running meets the requirements, that is, there is no friction sound, screaming sound, card sound and other abnormal sounds, otherwise it should be stopped for inspection.
