Compared to other complex machinery, electric motors are relatively easier to counterfeit. Therefore, some popular electric motors are dissected and copied by unscrupulous manufacturers. However, every electric motor manufacturer has its own unique characteristics in machining, winding, wiring, surface treatment, packaging, and labeling.
Regarding the wiring system of a motor, a good design will meet the needs of the motor manufacturing process, user wiring, and subsequent maintenance, while a low-level design or manufacturing will bring many inconveniences to the customer's later use and maintenance.
Motor wiring systems must meet safety requirements stipulated by relevant standards, including electrical clearances, creepage distances, current-carrying areas, and grounding. They must also reflect user-friendliness. After all, motor users may not be familiar with all aspects of motor technology. Ensuring that customers at every level can install and use motors in a simple and clear manner truly reflects a motor manufacturer's product knowledge and communication skills. Therefore, connectors, terminal blocks, lead wire markings, and terminal markings are all essential elements in the wiring system.
Requirements for flexible cables for motor products
If the motor has a power cord, or provides a lead cable extending out of the motor frame or housing for easy connection to other equipment, and a plug for connecting to the power supply line when necessary, such cord and plug shall comply with the relevant standards for the product or the requirements for cords in the relevant standards for this type of equipment.
●Voltage Requirements: The rated voltage of the lead-in flexible cable should not be lower than the maximum operating voltage of the motor, and its current carrying capacity should be at least equal to the load current of the service factor or 125% of the full-load rated current, whichever is greater. The insulation of the flexible cable should be able to withstand the power frequency withstand voltage test of the circuit.
● Grounding Requirements: Unless grounding is not required, one grounding conductor should be included in these flexible cord bundles. Lead-in cords should include ends and should be clearly distinguishable by different colors or markings.
●Protection requirements: Unless otherwise implemented, measures should be taken to eliminate potential tension, or the flexible cable should not be exposed outside the motor. An insulating protective layer and clamping device should be installed at the point where the flexible cable exits to prevent external tension from being transmitted to the internal wiring and to prevent accidents caused by the rotation or displacement of the flexible cable.
Unless otherwise protected, the lead cable should be prevented from retracting into the motor. Clamping devices used to clamp and secure the lead cable should be made of insulating material; if made of metal, they should have an insulating lining.
The clamping device for the lead-in flexible cable should be inspected to ensure it meets requirements and should be determined through tensile and torsional tests as specified in the standard. The lead-in flexible cable should not be forcibly inserted through the inlet hole to prevent insulation damage.
●Free length requirement: The free length of the loose lead cable used for field wiring inside the junction box should be at least 150mm.
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