Motor Current Signature Analysis (MCSA)

Motor Current Signature Analysis (MCSA) is a Condition Monitoring technique that allows diagnosis of many induction motor issues relating to the rotor such as broken bars or cracked end-rings along with diagnostics of loading and operating conditions.

The technique is non-intrusive allowing tests to be performed on-line and in service under normal operating conditions. The technique is suitable for induction motors over 37.55 kW and with advances in technology is able to work down to loads of 35% Full Load Current (FLC), half of what used to be the norm.

There are 2 main categories of MCSA tests:

• Traditional: this is where you are looking at the FFT of the current wave form to identify issues such as:
o Broken Rotor Bars
o Eccentricity (Air Gap)
o High resistance joints
o Cracked end rings
• Torque: this is where you convert the monitored current of all the Phases in to Electrical Torque, by looking at the waveforms and FFT of this Torque it is possible understand any modulation that is taking place and can indicate issues such as:
o Torque pulses – both load and supply induced
o Bearing faults
o Operating Conditions