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e-CFR data is current as of November 24, 2020

Title 40Chapter ISubchapter CPart 90Subpart D → §90.305


Title 40: Protection of Environment
PART 90—CONTROL OF EMISSIONS FROM NONROAD SPARK-IGNITION ENGINES AT OR BELOW 19 KILOWATTS
Subpart D—Emission Test Equipment Provisions


§90.305   Dynamometer specifications and calibration accuracy.

(a) Dynamometer specifications. The dynamometer test stand and other instruments for measurement of speed and power output must meet the engine speed and torque accuracy requirements shown in Table 2 in Appendix A of this subpart. The dynamometer must be capable of performing the test cycle described in §90.410.

(b) Dynamometer calibration accuracy. (1) The dynamometer test stand and other instruments for measurement of power output must meet the calibration frequency shown in Table 2 in Appendix A of this subpart.

(2) A minimum of three calibration weights for each range used is required. The weights must be equally spaced and traceable to within 0.5 percent of National Institute for Standards and Testing (NIST) weights. Laboratories located in foreign countries may certify calibration weights to local government bureau standards.

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