Figure 1: Motor condition monitoring with motor circuit analysis and TVS technology. Source: ALL-TEST ProFigure 1: Motor condition monitoring with motor circuit analysis and TVS technology. Source: ALL-TEST Pro

Why test motors?

Because motors fail. Not all winding faults start as ground faults. Instead, they can start as a weakness in the winding insulation system that may eventually fault to ground when the motor stops running. Motor testing is integral to the success and efficiency of a business. Get the motor health data necessary to make a quick and informed decision.

When to test motors?

  • Test newly installed motors to ensure proper installation and prevent startup failure.Figure 2: Not all winding faults start as ground faults. Source: ALL-TEST ProFigure 2: Not all winding faults start as ground faults. Source: ALL-TEST Pro
  • Test motor spares to ensure they are in good condition and ready for service.
  • Troubleshoot motors that have quit running by testing from the MCC or at the motor.

Test methods

Megohmmeter: Megohmmeter insulation testing only detects faults to ground. Since only a portion of motor electrical winding failures begin as ground faults, they will go undetected using this method alone. Moreover, surge testing requires the application of high voltages. This can be destructive when testing a motor, making it an unsuitable method for troubleshooting and true predictive maintenance testing.

Multimeter: While multimeters are valuable tools for motor testing, there are some downsides to consider with these issues:

Figure 3: MCA is a deenergized test method to assess the health of a motor. Source: ALL-TEST ProFigure 3: MCA is a deenergized test method to assess the health of a motor. Source: ALL-TEST Pro

Deenergized testing and Motor Circuit Analysis (MCA)

Motor Circuit Analysis (MCA) is a deenergized test method to assess the health of a motor. Initiated from the motor control center (MCC) or directly at the motor itself, this process evaluates the entire electrical portion of the motor system, including the connections and cables between the test point and motor.

Motor testing using MCA tools is very easy to implement, and the test takes less than three minutes. Save money and time by proactively detecting developing faults before they cause irreversible motor failures.

Figure 4: Motor testing using MCA tools is very easy to implement. Source: ALL-TEST ProFigure 4: Motor testing using MCA tools is very easy to implement. Source: ALL-TEST Pro

Deenergized testing applications

Too often, equipment operators won’t seek help until a motor starts to make a grinding noise. MCA tools are ideal in the following areas:

  • AC/DC motors
  • AC/DC traction motors
  • Generators/alternators
  • Machine tool motorsFigure 5: ALL-TEST Pro MCA tools apply a series of low voltage, non-destructive, sinusoidal AC signals through the motor to measure the response of these signals. Source: ALL-TEST ProFigure 5: ALL-TEST Pro MCA tools apply a series of low voltage, non-destructive, sinusoidal AC signals through the motor to measure the response of these signals. Source: ALL-TEST Pro
  • Servo motors
  • Control transformers
  • Transmission and distribution transformers (virtually any size)
  • For commissioning testing
  • For troubleshooting
  • For reliability testing

How does it work?

The electrical portion of the three-phase motor system is made up of resistive, capacitive and inductive circuits. When low-voltage is applied, healthy circuits should respond in a specific way.

ALL-TEST Pro MCA tools apply a series of low voltage, non-destructive, sinusoidal AC signals through the motor to measure the response of these signals. This deenergized test takes only a few minutes and can even be performed by an entry-level technician.

MCA measures:

  • Resistance
  • Impedance
  • Inductance
  • Fi (phase angle)
  • Dissipation factor
  • Insulation to ground
  • I/F (current frequency response
  • Test value static (TVS)
  • Dynamic stator and rotor signatures

Look for instruments that test if a motor is safe, easy and dependable. Here are some motor test instruments by All-Test Pro:

Summary

Complete motor health assessment: The electrical health of all motor components is evaluated, including, but not limited to induction windings, rotors and all associated connections and cables.

Patented test value static (TVS): TVS technology uses a proprietary algorithm to create an overall ‘machine health’ value from a quick, three-phase test that analyzes impedance, inductance, phase angle and current frequency, to trend over time.

Patented dynamic stator and rotor signatures: Used to evaluate the condition of the stator and squirrel-cage rotor in a single test. Perfect for testing new and repaired motors prior to acceptance.

See the All-Test MCA Product Comparison Chart

ALL-TEST Pro is a leading manufacturer of electric motor predictive maintenance (PdM) equipment and condition monitoring tools. ALL-TEST Pro electric motor testing devices surpass other instruments by accurately and quickly diagnosing motor health issues to ensure electric motor reliability and reducing unnecessary facility operational and repair costs. All diagnostic instruments are handheld and lightweight, making them exceptionally suitable for field testing applications. The current line of motor testing devices use MCA, a proprietary technology developed by ALL-TEST Pro, and electrical signature analysis, to evaluate electrical issues of components within motors. ALL-TEST Pro products are widely used in nearly every industry that uses electric motors, generators or transformers, and are available worldwide.