An essential step to ensuring a quality installation and reliable operation of a repaired or replacement motor is recording and verifying the motor data.

Use a motor data sheet to record the nameplate data and pertinent electrical and mechanical parameters at the time of installation and startup. These baseline values will be invaluable for determining the application’s life-cycle cost and recognizing any changes in operating characteristics. 

Here are eight steps you can take to document this data.

• Confirm that the motor is appropriate for the application by verifying that its mechanical and electrical characteristics are suitable for the intended application.

• For an adjustable-speed drive (ASD) or variable-frequency drive (VFD) application, use an “inverter-duty” motor (or provide suitable filtering) and keep the supply-cable length within the motor manufacturer’s guidelines. Use supply conductors designed for ASD circuits to reduce the risk of over voltages and transient voltages at the motor terminals, and a shaft grounding system or insulated bearings to prevent damage from stray shaft currents.

• Record the nameplate data. Serial numbers are usually coded to indicate the month and year of manufacture. For extra assurance, attach a digital photo of the nameplate for reference in case of errors in the recorded data.

• Make sure the motor’s bearings are suitable for the driven load, e.g., a drive end roller bearing for high- radial load-belted application.

• Review the manufacturer’s lubrication specifications and ensure the lubrication points are accessible.

• Using a digital low-resistance ohmmeter, record the temperature-corrected insulation resistance of the motor and the line-to-line resistance of the winding.

• Verify that the motor control and overload protection are sized properly for the motor rating.

• Inspect and test motors taken from storage to ensure they haven’t degraded. EP

Content adapted from EASA’s, St. Louis (easa.com), Getting the Most from Your Electric Motors. Access the full publication at go.easa.com/electricmotors.