EC8-S Copper Connector Temperature Rise Testing
In electric scooters, the conventional method for connecting motor phase wires to the controller involves securing them with screws to copper lugs.
This method is convenient as it only requires fastening two sets of phase wires onto a base with screws. However, it has consistently exhibited certain issues:
1. **Inconsistent Torque on Screws**
The inconsistent torque applied to the screws leads to operational faults in the vehicle. The phase wires may begin to heat up, causing the outer insulation of the wire harness to melt.
2. **Deformation of Base During Heating**
As the base heats up due to the high temperature of the copper lugs, it results in the loosening of screws, leading to poor phase wire contact. This further exacerbates the heating at the connection points, contributing to the melting of the phase wire insulation.
To ensure a reliable connection between themotor phase wires and the controller, riders need to frequently check if thescrews are properly tightened.
In pursuit of reducing the failure rate of phase wire connections and minimizing maintenance costs, we have been searching for a suitable alternative. Recently, we found a specialized manufacturer ofhigh-current connectors and have customized a connector, EC8-S.
(Left in the image above is EC8 connector, and on the right is the customized EC8-S connector which is the object we would use in this test).
The connector manufacturer claims that it can withstand a rated current of 150A and a maximum current of 200A. However, precise data is not currently available (e.g., what is the temperature rise when carrying a continuous current of 150A for 1 minute? Will the connectionfail at 200A?)
To determine if this connector can meet our requirements, we conducted an experiment: We connected the conventional screw-fastened copper lugs in series with the EC8-S connector.
In the figure above, the controller is CC1(60V45A), the meter is DS20, and the motor is (JL60V3000W22092393).
We use Fluke iSee TC01A Thermal Imagerto observe temperature rise in the circuit.
To account for differences in the infrared characteristics of different metal materials, we applied a layer ofinsulating tape to the connector.
During motor operation, we applied belt braking to provide resistance to the motor, testing it under high currentconditions.
**Test Video**
We measured temperatures at various points along the phase wire circuits:
Temperature near EC8-S connector
Temperature near screw-fastened copper lugs
Battery connector (XT60) and internalcontroller temperature measurements
**Conclusion**
Preliminary assessment indicates a lowertemperature rise for EC8-S. Further testing of EC8-S is planned.
**Plan**
As the EC8-S relies on metal elasticity forits contact, we intend to leave samples in place for an extended period andrepeat the tests to verify any changes in its characteristics. Additionally, we plan to install EC8-S on the scooter for further testing.