ELECTRICAL SIGNATURE ANALYSIS (ESA) FOR MOTOR AND GENERATOR DIAGNOSTICS

Electrical Signature Analysis (ESA) is a non-invasive, remote test that provides insight into the health of rotating equipment, such as motors or generators, and their components. It can identify a wide range of common problems with components including: bearings, windings, rotor bars, rotor laminations, stator laminations, power quality, gearbox, and wye rings.

ESA encompasses many different electrical analysis techniques including current signature analysis (CSA/MCSA), voltage signature analysis (VSA), and instantaneous power signature analysis (IPSA). Combining these different techniques provides a comprehensive characterization of motor and generator health that can be used to inform maintenance and replacement decisions.

ESA can be applied in a variety of industries, on basically any type of motor or generator. In the nuclear industry, critical motors associated with feedwater pumps, reactor coolant pumps, and even CRDM motor-generator sets are ideal candidates for the additional condition monitoring provided by ESA. In addition to nuclear power plants, wind turbines are another common application for ESA, as you can monitor the health of “up-tower” components from the tower base without having to install additional equipment.

MOTOR FAULTS IDENTIFIED BY ESA INCLUDE:

Winding Problems

Problems with Power Quality

Other Motor Internal Problems

Stator and Rotor Issues

Bearing Faults

Shaft Problems

Load Issues

Power Electronics Such As VFDS, Soft Starters, Etc.

Rotor Damage

 

To perform ESA testing, current and voltage data are collected from motor or generator leads, typically using current or voltage transducers. This raw data is then analyzed with a Fast Fourier Transform to generate a frequency spectrum from which information about the condition of key equipment components can be ascertained. ESA is primarily used to monitor the health of and diagnose issues with motors, generators, and their associated loads, but it is also applicable to other components, such as power electronics.
While most motors and generators can still operate despite some small problems, these issues will develop into more significant complications if undetected and unaddressed. With AMS’s ESA testing services, rotating equipment problems are detected early through a condition-based maintenance approach.

Changes in the ESA Spectra