(1) Starting from the power supply end according to the electrical schematic diagram or installation wiring diagram of the 4-Roller Plate Rolling Machine, check the wiring and wiring terminals section by section whether they are correct or not, and whether there is a missing or wrong connection.Check whether the wire contact meets the requirements and whether the pressing is firm.The contact should be good to avoid flash arc phenomenon when running with load.
The multimeter is used to check the on-off condition of the Plate Rolling Machine circuit.During the inspection, the electrical block with appropriate rate should be selected and the zero should be adjusted to prevent the occurrence of short circuit fault.Check the control circuit (can disconnect the main circuit), can be put on Ull, VLL line end, the reading should be ∞.Press the start button, the reading should be the resistance value of the contactor coil, and then disconnect the control circuit to check whether the main circuit is open or short circuit phenomenon, at this time can be manually operated mechanism to replace the contactor power to check.
③ The insulation resistance of the line should not be less than 0.5MFL when checked with the mehmmeter.
After being checked by the instructor, it is electrified and tested.
1) No-load debugging
Under the condition of not connecting the motor of the winding machine, close the power switch and press the forward rotation start button SB2 to observe whether the contactor KML is pulling, and then press the reverse start button SB3 to observe whether the contactor KM2 is pulling. If it is normal, it can be adjusted with load.
2) debug with load
When connecting the motor of the winding machine, close the power switch, press the forward turning start button SB2 to observe the operation of the motor, and then press the reverse starting button SB3 to observe the operation of the motor.
Remove the power line after the power is energized, and then remove the load line.
When choosing a thermal relay, it is necessary to understand the working environment, starting situation, load nature and other factors of the protected rolling machine object.The principle of selection is that the amps-second characteristic of the thermal relay is below and as close as possible to the overload characteristic of the motor.Generally, it should be selected from the following aspects.
2.1) Type of thermal relay
3.If the thermal relay is used as the phase-loss protection of the motor, the connection method of the coil motor should be considered.In the case of a star-connected motor, the current in the remaining unbroken phase windings increases in the same proportion as the current in the current overheating relay when one phase is disconnected.The general three-phase thermal relay, as long as the setting current is adjusted reasonably, can realize the phase-out protection for the star connection motor.For the triangular connection motor, when a phase is disconnected, the current flowing through the uninterrupted phase winding increases in a different proportion than the current flowing through the overheated relay, that is to say, the current flowing through the overheated relay cannot reflect the overload current of the winding after the phase is disconnected.Therefore, the general thermal relay, even the three-phase type can not provide sufficient protection for the three-phase asynchronous motor with triangular connection.At this point, a three-phase thermal relay with phase break protection should be selected.Models of thermal relays with phase-out protection are followed by D, T, or 3uA.
4.2) Rated current of thermal relay
5.The rated current of the thermal relay shall be selected as 1.1 ~ 1.15 times of the rated current of the motor of the protected coil machine.
6.3) Setting current of thermal relay
7.Generally, the setting current of the thermal relay of the coil machine is adjusted to be equal to the rated current of the motor;For the motor with poor overload capacity, the setting value of the thermal relay can be adjusted to 0.6-O-8 of the rated current of the motor.The setting current of the thermal relay should be adjusted to 1.1 ~ 1.15 times of the rated current of the motor for the motor that starts for a long time, drives the impact load or is not allowed to stop.The main technical parameters of low voltage electrical apparatus for plate shears