Motor junction box setting

Motor junction box setting

The setting of the motor junction box should be based on the motor type, wiring method, and safety regulations. The specific requirements are as follows:

1、 Selection of junction box type

Matching of wiring methods

Star connection method: suitable for light load start-up or regular operation, connect the ends U2, V2, and W2 of the three-phase winding to the neutral point, and connect the ends L1, L2, and L3 respectively.

Triangle connection method: suitable for high load scenarios, directly connect the ends of the three-phase windings.

Switched Reluctance Motor: A dedicated junction box is required, including an insulation box and shielded wire terminal blocks, to ensure correct connection of phases A, B, C and shielding layer.

Specification parameter matching

Select the junction box corresponding to the rated current and voltage level based on the motor power, voltage, and current, ensuring that the number and layout of internal wiring terminals in the junction box meet the requirements.

2、 Wiring specifications

Wire connection

Three phase power cord: red (L1), yellow (L2), and black (L3) are respectively inserted into the corresponding wiring terminals; Connect the blue wire (N), brown wire (L), and yellow green dual color wire (PE) to the power cord.

The wiring should be firm, and insulated tape should be used to wrap the wiring points to prevent short circuits.

Division and Protection

Install a distribution board inside the junction box to separate incoming and outgoing lines for easy maintenance.

An overload protector or circuit breaker needs to be installed to prevent overload.

Shielding layer treatment

Switched reluctance motors require the addition of shielded wire terminals at the A, B, and C phase terminals, with the shielding layer grounded to reduce interference.

3、 Installation requirements

Physical installation

Choose a location with good ventilation and easy maintenance to avoid interference with other equipment.

The inlet hole of the motor junction box should be reserved with sufficient length, and the length of the cable should not be too long or too short.

Grounding and Protection

The grounding wire (yellow green dual color wire) should be reliably connected to the grounding hole to ensure that the grounding resistance meets the specifications.

The metal casing of the junction box needs to be grounded, and it is recommended to use a dedicated grounding device for small-sized motors.

4、 Precautions

safe operation

When wiring, power should be cut off and insulated tools should be used to avoid the risk of electric shock.

Regular maintenance

Check if the wiring terminals are loose, if the insulation layer is damaged, and replace aging components in a timely manner.

Standardized identification

The junction box should be clearly labeled, including information such as voltage, number of phases, grounding symbol, etc.

By setting the above specifications, the safety, reliability, and ease of maintenance of the motor junction box can be ensured, and the service life of the equipment can be extended.