What is the difference between the routine test and the type test for high-voltage three-phase asynchronous motors?

The core difference between the routine test (factory test) and the type test for high-voltage three-phase asynchronous motors is:

The routine test is a "factory pass certificate" performed on every motor to verify the manufacturing quality of each unit. The type test is a "design validation report" performed on a sample from the same specification to verify the design and performance compliance of the entire series.

I. Core Purpose and Scope of Application

1. Routine Test (Factory Test)

• Object: Every completed motor – 100% inspection.

• Purpose: To identify manufacturing defects (incorrect winding connections, poor insulation, assembly errors, etc.), ensure each motor meets basic safety and operational requirements, and be allowed to leave the factory only if it passes.

• Trigger condition: Mandatory after each motor is manufactured, no exceptions.

2. Type Test

• Object: One sample motor of the same specification/series (first unit, after design/process changes, or after long-term production resumption).

• Purpose: To comprehensively verify whether the design rationality, performance indicators, temperature rise, efficiency, mechanical characteristics, etc., of the motor series comply with standards and technical agreements, providing a basis for batch production.

• Trigger conditions (any one requires re-testing):

  I. First trial production / small batch production of a new product;

  II. Major changes in design, materials, or processes (affecting performance);

  III. Resumption of production after a long-term shutdown (≥2 years);

  IV. Updates to national/industry standards;

  V. Specific requirements from users or certification bodies.

II. Comparison of Test Items (primarily based on GB/T 1032-2023)

1. Routine Test (Mandatory Items)

• Cold-state DC resistance measurement of windings (three-phase balance)

• Insulation resistance measurement (≥1 MΩ/kV for high-voltage motors)

• Power-frequency withstand voltage test (2×Un+1000V, 1 min, no breakdown/flashover)

• Inter-turn insulation impulse voltage withstand test

• No-load test (no-load current, loss, speed, vibration, noise)

• Locked-rotor test (locked-rotor current, torque)

• Appearance, dimensions, and wiring check

2. Type Test (includes all routine test items + in-depth performance items)

• Includes all routine test items

• Temperature rise test (stable temperature rise under rated load, verifying insulation thermal durability)

• Efficiency and power factor determination (at different load points, verifying energy efficiency indicators)

• Load characteristic test (torque-speed curve, current-torque curve)

• Short-time over-torque test (1.6–2.5 times rated torque, verifying mechanical strength)

• Moment of inertia determination

• Overspeed test (1.2 times maximum speed, verifying rotor strength)

• Precise vibration and noise measurement (according to GB/T 10068/10069)

• Shaft voltage and bearing current measurement

• Special operating condition tests (e.g., frequent starting, braking, frequency converter adaptation)

III. Summary of Key Differences

 IV. Conclusion

• The routine test is the  "factory threshold" – it ensures each motor is usable and safe.

• The type test is the "design ceiling" – it proves that the motor series meets performance specifications and has a reliable design.

• In actual production: the type test is performed first for design validation, then each motor undergoes the routine test according to the validated standards. Both are indispensable.