The Growing Demand for Electric Motorcycle Motor Validation
Electric two-wheelers are one of the fastest-growing segments of the global EV market. From high-performance e-motorcycles competing with 125cc–600cc petrol bikes to lightweight electric mopeds replacing scooters across Southeast Asia and the Middle East, the range of drive motor specifications is enormous — and so are the testing requirements.
Unlike passenger EV motors, electric motorcycle drive motors face unique challenges: high peak-to-continuous torque ratios (the rider expects instant throttle response), severe vibration environments, and the need to pass national type-approval tests before sale. In China, this means compliance with GB/T 7258 and the motor-specific standard GB/T 36979. For export markets, CEI 60034 and regional regulations apply.
How an Electric Motorcycle Motor Differs from an Industrial Motor
Motor test engineers moving from industrial to e-moto applications quickly encounter several differences:
- High peak-to-rated ratio: E-moto motors typically deliver 3–5× rated torque for 30–60 seconds — much higher than industrial servo motors
- Controller integration: The motor is always tested with its dedicated controller; performance is a system property, not a motor-only property
- CAN bus communication: Modern e-moto controllers communicate via CAN — the test bench must interface with the CAN network to read controller diagnostic data
- Wide speed range: Hub motors for mopeds operate at 200–1,000 rpm; mid-drive motors for performance bikes reach 5,000–10,000 rpm before reduction gearing
- Thermal sensitivity: Compact motor packages have limited cooling — thermal testing is more critical than for larger industrial motors
Test Items per GB/T 36979 et GB/T 7258
1. Continuous Torque Test
The motor and controller run at rated voltage with torque increasing until the rated continuous torque is reached. The system must sustain rated continuous torque for 30 minutes with temperature rise not exceeding the specified limit for the motor’s insulation class.
Why it matters: Continuous torque determines legal classification — bikes that cannot sustain rated torque for 30 minutes may be reclassified as lower performance vehicles, affecting insurance and licensing requirements in many markets.
2. Continuous Power Test
Similar to the continuous torque test, but the load is set to deliver rated continuous power output (torque × speed = constant power). The 30-minute sustain requirement applies equally.
3. Peak Torque Test
The motor is run at rated voltage, with load applied until peak torque (specified in the product technical file) is reached. Duration requirements:
- Electric motorcycle (摩托车): Peak torque sustained for 60 secondes
- Electric moped / light motorcycle (轻便摩托车): Peak torque sustained for 30 secondes
Temperature rise must not exceed limits at test end. This test is the most thermally demanding in the validation sequence.
4. Peak Power Test
Same duration requirements as peak torque test. Peak power is typically 2–4× continuous power for performance e-motos. The test bench must be able to apply the required load within 1–2 seconds of the start of the timed interval.
5. Maximum Working Speed Test
With rated voltage applied, the controller commands maximum speed. A load of at least the minimum specified by the product technical file is applied. The motor must maintain stable operation at maximum working speed for not less than 3 minutes.
6. Rated Speed Test
The motor runs at rated voltage with load increasing until rated torque is reached. This establishes the S1 (continuous) rated speed under full-load conditions — the reference point for the T-N curve and efficiency testing.
7. External Characteristic Curve (T-N Curve)
The full torque-speed curve from zero speed to maximum speed at rated controller voltage. As with all servo/traction motor T-N curves, this maps the continuous operating envelope. For e-moto applications, the curve is especially important because the legal maximum speed is derived from this curve under load — not from free-running no-load speed.
8. Tests d'efficacité
Efficiency is measured at five torque points as a fraction of rated torque:
| Test Point | % of Rated Torque | Typical Efficiency Target |
|---|---|---|
| Light load | 50% | >75% |
| Partial load | 80% | >82% |
| Charge nominale | 100% | >85% |
| High load | 150% | >82% |
| Peak load | 200% | >75% |
The test procedure: motor at rated voltage and rated speed, brought to thermal equilibrium (S1 duty per GB/T 755-2019), then torque stepped through each measurement point. System efficiency = mechanical output power / electrical input power (measured at controller DC input).
Test software efficiency chart showing five measurement points plotted on efficiency vs torque axis with GB/T compliance markers
Test Bench Configuration for Electric Motorcycle Motors
Composants système
| Component | Spécification | Notes |
|---|---|---|
| Load dynamometer | AC servo, 15–50 kW, 0–10,000 rpm | Four-quadrant for regeneration simulation |
| Torque-speed sensor | 0–500 N·m, ±0,1 % FS | Sized for peak torque, not rated torque |
| Power analyzer | 4-channel, 600V / 500UN | DC input + 3-phase AC output of controller |
| Motor performance analyzer | WH series, 0.2% précision | Simultaneous electrical + mechanical capture |
| CAN communication card | CAN 2.0A/B | Reads controller fault codes and parameters |
| Data logger | 16-channel thermocouple | Winding, palier, housing temperatures |
| Bidirectional DC power supply | 0–120V / 0–500A typical | Simulates battery pack voltage |
| Chambre environnementale | -20°C to +60°C (facultatif) | Cold-start and high-ambient testing |
| Safety guard | Full enclosure, interlock | Required for high-speed shaft |
CAN Interface: Pourquoi c'est important
Modern e-moto controllers communicate motor speed commands, torque limits, and fault conditions via CAN bus. Without a CAN interface card in the test bench, engineers cannot:
- Read actual motor speed from the controller’s encoder (versus the test bench speed measurement)
- Monitor controller fault codes in real time during testing
- Command speed/torque via the controller’s native protocol (required for some OEM acceptance tests)
- Log controller temperature and current limit data alongside bench measurements
Dyno Sizing: Peak Torque Is the Design Driver
A critical sizing mistake is selecting the load dynamometer based on rated (continuous) torque rather than peak torque. If the motor’s peak torque is 3× rated, the dyno must be sized to absorb 3× rated torque — even if this condition lasts only 60 secondes. Undersizing the dyno means it enters thermal protection before the motor’s peak torque test completes, invalidating the test result.
Common Testing Challenges and Solutions
Challenge: High Peak Torque Requires Massive Fixture Loads
Solution: Both the motor and dynamometer must be mounted on a rigid sliding rail system so that the reaction torque during peak torque tests is absorbed by the fixture, not the shaft coupling. The coupling alignment must be set with the motor at operating temperature — thermal expansion changes shaft alignment and can cause false torque readings.
Challenge: Controller vs. Motor Efficiency Separation
Solution: Install the power analyzer’s DC voltage and current measurement at the battery/supply terminals (controller input). The 3-phase AC measurement goes at the controller output (motor input). This gives three efficiency figures: controller efficiency, motor efficiency, and overall system efficiency — all from a single test run.
Challenge: Temperature Measurement in Compact Motors
Solution: For compact hub motors with no accessible winding end turns, surface thermistors bonded to the stator outer diameter are used as a proxy for winding temperature. A calibration curve (surface temperature vs. température d'enroulement) must be established during R&D testing.
Foire aux questions
What is the difference between GB/T 36979 et GB/T 7258 for electric motorcycle testing?
GB/T 36979 is the motor-specific standard covering performance test methods for electric motorcycle and moped drive motors (couple, pouvoir, efficacité, thermal tests). GB/T 7258 is the broader vehicle standard for motorcycles and mopeds — it references GB/T 36979 for motor test methods and adds vehicle-level requirements for braking, éclairage, and safety systems.
Does an electric motorcycle motor test bench need to simulate regenerative braking?
For complete system validation, yes. Many high-performance e-moto controllers include regenerative braking capability. Testing regeneration efficiency requires a four-quadrant dynamometer that can drive the motor shaft (simulating the wheel driving the motor during deceleration). For basic type-approval testing, regeneration is typically not required.
What is the minimum accuracy needed for e-moto motor testing?
GB/T 36979 requires measurement uncertainty of ≤0.5% for torque, ≤0.2% for speed, and ≤0.5% for electrical power. These requirements drive the instrument specifications for the test bench — particularly the torque sensor (±0.1% FS minimum) and power analyzer (±0.05% to ±0.2% accuracy class).
Can the same test bench test both hub motors and mid-drive motors?
Oui, with appropriate coupling adapters. Hub motors require an adapter to connect the wheel hub flange to the torque sensor. Mid-drive motors connect directly via a standard motor shaft coupling. Switching between configurations typically takes 30–60 minutes for mechanical reconfiguration.
Conclusion
Electric motorcycle motor testing requires a test bench that can handle high peak torques, interface with controller CAN bus, and execute the full GB/T 36979 test sequence automatically. Getting it right before type-approval submission saves weeks of rework and avoids costly retests.
EconoTest’s e-moto motor test benches cover motors from 1 kw à 100 kW continuous, with peak torque capability up to 5× rated, full CAN interface, and automated GB/T 36979 compliant test reports.
→ Request a configuration matched to your motor and controller specifications.
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