Electric Circuit

Analysis

Resistance

Inductance

Capacitance

Impedance

Electric Circuit Analysis (ECA) evaluates the condition of an electric circuit while the asset is off-line (not operating). When applied to motors or generators, it is often called Motor Circuit Analysis (MCA). ECA technologies are relatively simple low voltage tests which include resistance, capacitance and inductance. When stated as a complex value they are called impedance. ECA tests are used on motors, generators, transformers, switch gear, cables and all electrical connections.

Diagnose Non Voltage Dependent Problems

ECA tests identify failures only after they are already affecting the electrical system. ECA tests are especially beneficial in identifying issues which are not voltage dependent. Torq uses ECA tests mostly to help confirm that new equipment is installed properly prior to powering up the equipment and as a first step in troubleshooting or identifying a failed asset. Common uses of these tests are to check for high resistance connections, to check for misconnected/mislabeled leads especially on dual voltage or wye/delta type windings, and to help identify squirrel cage rotor failures (RIC test).

ECA Limitations

Sometimes maintenance techs believe that ECA tests are more predictive than they really are. A common false belief is that ECA can identify developing insulation issues well before they affect the operation of the electrical system. Sometimes a motor will pass the ECA tests and then fail very soon after testing. And it is not uncommon for a motor to pass the ECA tests even after it has already failed catastrophically. This happens because the operating voltage of the motor is much greater than the applied voltage of these tests. A motor can have a short at line voltage, but, appear to be okay when tested with a low voltage meter. Low voltage tests have fairly limited application as predictive testing tools. ECA tests must be coupled with other technologies as part of an effective predictive insulation testing program.

Torq Engineering has full knowledge of the capabilities and limitations of ECA testing. Please contact us if you would like to find out more.

More information on ECA Testing is available in our Knowledge Center.