ETENWOLF S3 Cordless Tire Inflator Motor Load Current Test Report (21000 RPM)

Document Overview

Key Findings The ETENWOLF S3 motor was tested at 21000 RPM across a full load sweep from 10 PSI to 160 PSI, with both sample units (7# and 8#) remaining within expected current draw ranges throughout the entire operating envelope. Test Type: Motor Load Current…

Document type

Test Report

Prepared by

Daniel Wright

Published

July 22, 2026

Last reviewed

July 22, 2026

Topics

Motor Performance

Key Findings

The ETENWOLF S3 motor was tested at 21000 RPM across a full load sweep from 10 PSI to 160 PSI, with both sample units (7# and 8#) remaining within expected current draw ranges throughout the entire operating envelope.

• Test Type: Motor Load Current Measurement
• Motor Speed: 21000 RPM
• Load Range: 10.0 – 160.0 PSI
• Sample 7# Peak Current: 9.6 A (at 70–80 PSI)
• Sample 8# Peak Current: 9.9 A (at 70 PSI)
• Test Date: 2025-07-01
• Both samples exhibited consistent bell-curve current profiles, peaking in the mid-load range and tapering at high loads.

Test Overview

Test Equipment & Setup

Test Procedure

1. Pre-Test: Verify motor assembly and confirm unit is designated sample 7# or 8#. Ensure motor is at ambient temperature before starting.
2. Setup: Connect motor to test rig configured for 21000 RPM operation. Attach calibrated current measurement instrument in series with the motor power supply.
3. Load Sweep: Apply incremental pressure loads starting at 10.0 PSI. At each load step, allow current to stabilize, then record the steady-state current value in Amperes.
4. Step Increment: Increase load in 10.0 PSI steps up to and including 160.0 PSI, recording current at each step.
5. Repeat: Perform the identical procedure for the second sample unit.
6. Post-Test: Power down test rig. Record test date and consolidate all readings into the data table.
7. Acceptance Criteria: Current values must remain within the safe operating range of the motor across the full load sweep. No thermal runaway or uncontrolled current rise should occur.

Test Data & Results

Observations: Both samples demonstrate a characteristic bell-curve current profile. Current rises from approximately 6.8–7.3 A at minimum load (10 PSI) to a peak of 9.6 A (7#) and 9.9 A (8#) in the 70–80 PSI range, then decreases steadily back to 7.4–7.5 A at maximum load (160 PSI). Sample 8# consistently reads slightly higher current than 7# across most load points, with the two samples converging at 30 PSI (both 8.7 A), 80 PSI (both 9.6 A), 150 PSI (both 7.6 A), and 160 PSI (7.4 A vs 7.5 A). The current taper at high loads is consistent with expected back-EMF behavior as the motor compresses against higher resistance.

Conclusion

Document Information

Frequently Asked Questions

What is the peak current draw of the ETENWOLF S3 motor during load testing?

During the 21000 RPM load current test, the ETENWOLF S3 motor reached a peak current of 9.9 A on Sample 8# at a load of 70 PSI, and 9.6 A on Sample 7# at 70–80 PSI. Both values are within the normal operating range for this motor class.

At what pressure load does the S3 motor draw the most current?

The S3 motor peaks in current draw in the 70–80 PSI range. This mid-range peak is consistent with typical compressor motor behavior, where mechanical resistance is highest before the load taper effect from increased back-EMF takes over at higher pressures.

How does S3 motor current behave at high inflation pressures above 100 PSI?

Above 100 PSI, current draw decreases progressively for both samples. By 160 PSI, current had dropped to 7.4 A (Sample 7#) and 7.5 A (Sample 8#), compared to their respective peaks near 70–80 PSI. This tapering pattern is normal and indicates the motor is operating as designed under high back-pressure conditions.

Were there any differences in current draw between the two S3 motor samples tested?

Sample 8# showed slightly higher current readings than Sample 7# at most load points, with the largest gap of 1.0 A occurring at 50 PSI (9.5 A vs 9.0 A) and 110 PSI (9.6 A vs 8.6 A). The two samples converged at 30 PSI, 80 PSI, 150 PSI, and 160 PSI, indicating normal unit-to-unit variation within acceptable manufacturing tolerances.

Related Products

Explore the full ETENWOLF S3 cordless tire inflator and related test documentation:

• ETENWOLF S3 Cordless Tire Inflator — Product Page
• ETENWOLF Inflation Tools — Full Product Range

Sibling Test Sheets (same Excel file):

• Sheet2 — Additional S3 test data from the same test session (S3-负载电流数据2025.7.1.xls)