QJX5 series power control box

1、 Purpose:
The QJX5 series power control box is suitable for starting, running, and stopping three-phase squirrel cage induction electric motors with AC 50Hz (or 60Hz) voltage of 380V and power below 75KW in AC-3 using "Y - △" switching. And it has phase loss and overload protection.
The QJX5 series power control box is not suitable for use in the AC-4 category.  

2、 Type
1. Structural form
There are three AC contactors, one thermal relay, one time relay and control button, signal indicator lights, control circuits, fuses, and appropriate wire terminals inside the control box. There are ammeters and transformers for 55KW and 75KW.
2. Model meaning

3. Appearance and installation dimensions
3、 Starting method
When starting the motor with the "Y" connection, the starting current is only one-third of that when starting at full voltage. When the speed reaches around 80% after starting, it is replaced with the "△" connection for operation, and the replacement time is set by the time relay.
4、 Correct usage method:
1. The external power supply should be connected to the three terminals L1, L2, and L3. To ensure safety, it is necessary to safely connect to the neutral (ground). The six connectors of the motor should be connected to U1, V1, W1, U2, W2, and V2 inside the box, and must not be connected incorrectly. Check if all screws are tightened;
2. The current of the thermal relay is set at the factory and cannot be adjusted arbitrarily by the user. The setting current of the thermal relay is the rated current of the motor multiplied by 1/≈ 0.58;
3. When the motor fails and stops running, the user should ask an electrician to check the cause of the fault and replace the components. If the thermal relay protection is activated due to excessive current, wait for 3-5 minutes and press the blue reset button of the thermal relay. After resetting, it can resume operation.
4. The time relay is set to around 7 seconds when it leaves the factory. Users can adjust the starting time according to the load, but the time should not exceed 15-20 seconds, otherwise it may cause damage to the AC contactor and motor.
5. Difficulty in starting (prolonged time) and only hearing one suction sound indicates damage to the time relay. If you hear one suction sound and another release sound (relatively low sound), it indicates damage to the 2KM or time relay. If the AC contactor operates normally, please check for machine malfunctions that may cause excessive starting torque.
6. Cannot start, possibly due to lack of power or blown fuse. At this time, the indicator lights inside the buttons on the panel are not on. Otherwise, it may be a thermal relay tripping action. Please wait for 3-5 minutes and then press the blue reset button on the thermal device.
7. Do not open the electric control box door during work, and do not use mechanical methods to force the contactor to turn on or off; Otherwise, our factory will not be responsible for any personal or equipment accidents caused.
8. Electrical schematic diagram, attached to the control box panel.

QJX5 series power control box