Deenergized Motor Circuit Analysis™ (MCA) Testing Instrument

The ALL-TEST PRO 31™ (AT31™) goes far beyond the capabilities of traditional Meg-Ohm-Meter testing. It detects faults that the Meg-Ohm-Meter and Digital Multimeter are not able to, ensuring that you have a more complete view into the condition of your motor’s health. A rotor test helps you detect rotor issues such as broken rotor bars and eccentricity.

The ALL-TEST PRO 31™ is the perfect tool for troubleshooting, start-up & quality control of low voltage AC Induction Motors. With unmatched portability, ease of use, and safety features, it enables technicians to efficiently evaluate equipment in the field, on the shop floor, or at a service facility. Arm your technicians with a light, inexpensive hand-held instrument that provides safer and more complete deenergized motor testing and help them save hours that might be spent on outdated troubleshooting methods using a megohmmeter.

Finding just one fault using the AT31™ can save your organization countless hours of downtime and provide thousands of dollars in savings. Maximize your investment by:

  • Testing newly installed motors to ensure proper installation and prevent startup failure.
  • Testing motor spares to ensure they are in good condition and ready for service.
  • Troubleshooting motors that have quit running by testing from the MCC or directly at the motor.

Tests AC motors <1000V. The electrical health of motor components is evaluated, including induction windings, associated connections 1, and cables. Rotor faults: broken bars, air-gaps, casting voids, etc.2

1 Detects open connections.
2 A fast, easy and effective way to find broken rotor bars, eccentric rotors and casting voids. AT31™ testing range is dependent upon the motor, transformer, or generator design, but the AT31™ has successfully tested AC motors of hundreds of horsepower in size.

  • Tests take less than 3 minutes
  • Measures Impedance (Z), Phase Angle (Fi), Current/Frequency Response (I/F) and insulation to ground resistance (500V or 1000V test voltage)
  • Detects faults before motor failure
  • Detects rotor faults
  • Condition Calculator™ Software – Test and Analysis Reporting


Product Brochures and Specs

Product Case Studies


Typically there are two sets of windings on a single phase motor Start/Run. Any capacitor must be disconnected. First, measure the start winding. With the run winding engaged, take your next set of readings. These can be trended over time or compared to a known good motor of the exact same kind.
No. The AT31™ uses a 9 pin db connector and only leads provided by ATP should be used.



Included Accessories

ALL-TEST PRO 31™ Test Lead
Test Lead Assembly
ALL-TEST PRO 31™ Battery Charger
Battery Charger

Optional Accessories

ALL-TEST PRO 31™ Test Lead Assembly
Test Lead Assembly (6ft/2m)
ALL-TEST PRO 31™ Armature Test Fixture
Armature Test Fixture
ALL-TEST PRO 31™ Battery Charger
Battery Charger
ALL-TEST PRO 31™ Training Motor
Training Motor
ALL-TEST PRO 31™ Universal Soft Case Clear Face
Universal Soft Case Clear Face