(a) Overview. This section describes the overall process for verifying and calibrating the performance of chassis dynamometers.
(b) Scope and frequency. The following table summarizes the required and recommended calibrations and verifications described in this subpart and indicates when they must occur:
Table 1 of § 1066.215 - Summary of Required Dynamometer Verifications
| Type of verification | Minimum frequencya |
|---|---|
| § 1066.220: Linearity verification | Speed: Upon initial installation, within 370 days before testing, and after major maintenance. Torque (load): Upon initial installation and after major maintenance. |
| § 1066.225: Roll runout and diameter verification | Upon initial installation and after major maintenance. |
| § 1066.230: Time verification | Upon initial installation and after major maintenance. |
| § 1066.235: Speed measurement verification | Upon initial installation, within 370 days before testing, and after major maintenance. |
| § 1066.240: Torque (load) transducer verification | Upon initial installation, within 7 days of testing, and after major maintenance. |
| § 1066.245: Response time verification | Upon initial installation, within 370 days before testing, and after major maintenance. |
| § 1066.250: Base inertia verification | Upon initial installation and after major maintenance. |
| § 1066.255: Parasitic loss verification | Upon initial installation, after major maintenance, and upon failure of a verification in § 1066.270 or § 1066.275. |
| § 1066.260: Parasitic friction compensation verification | Upon initial installation, after major maintenance, and upon failure of a verification in § 1066.270 or § 1066.275. |
| § 1066.265: Acceleration and deceleration verification | Upon initial installation and after major maintenance. |
| § 1066.270: Unloaded coastdown verification | Upon initial installation, within 7 days of testing, and after major maintenance. |
| § 1066.275 Dynamometer readiness verification | Upon initial installation, within 1 day before testing, and after major maintenance. |
(c) Automated dynamometer verifications and calibrations. In some cases, dynamometers are designed with internal diagnostic and control features to accomplish the verifications and calibrations specified in this subpart. You may use these automated functions instead of following the procedures we specify in this subpart to demonstrate compliance with applicable requirements, consistent with good engineering judgment.
(d) Sequence of verifications and calibrations. Upon initial installation and after major maintenance, perform the verifications and calibrations in the same sequence as noted in Table 1 of this section, except that you may perform speed linearity verification after the verifications in §§ 1066.225 and 1066.230. At other times, you may need to perform specific verifications or calibrations in a certain sequence, as noted in this subpart. If you perform major maintenance on a specific component, you are required to perform verifications and calibrations only on components or parameters that are affected by the maintenance.
(e) Corrections. Unless the regulation directs otherwise, if the dynamometer fails to meet any specified calibration or verification, make any necessary adjustments or repairs such that the dynamometer meets the specification before running a test. Repairs required to meet specifications are generally considered major maintenance under this part.