The new Fluke 438-II Power Quality and Motor Analyzer adds critical mechanical measurement capabilities for electric motors to the advanced power quality analysis features of the Fluke 430 II Series. It measures and analyzes essential electrical and mechanical performance parameters—such as power, harmonics, unbalance, motor speed, torque, and mechanical power—without the need for mechanical sensors.

As an ideal portable motor analysis tool, the 438-II helps locate, predict, prevent, and troubleshoot power quality issues in three-phase and single-phase power distribution systems, while providing technicians with the necessary mechanical and electrical information to effectively evaluate motor performance.

Key Features:

• Comprehensive Motor Measurement: Measures key parameters on direct-on-line motors and specific VFD-driven systems, including torque, RPM, mechanical power, and motor efficiency.

• Dynamic Analysis: Performs dynamic motor analysis by plotting motor derating factors against load according to NEMA guidelines.

• Sensorless Measurement: Calculates mechanical power and efficiency by simply connecting to input conductors, eliminating the need for mechanical sensors.

• Electrical Health Monitoring: Identifies characteristics affecting motor efficiency by measuring voltage, current, power, harmonics, and unbalance.

• Power Quality Diagnostics: Detects dips, swells, transients, and harmonics.

• PowerWave Technology: Captures fast RMS data and displays half-cycle averages and waveforms to characterize electrical system dynamics (e.g., generator start-ups, UPS switching).

• Waveform Capture: Automatically records 100/120 cycles (50/60 Hz) of every detected event.

• High-Speed Transient Mode: Simultaneously captures waveform data up to 6 kV at 200 kS/s across all phases.

Mechanical Measurement Functions

• Motor Torque: Calculates the amount of rotational force (displayed in lb.ft or Nm) developed by the motor and transmitted to the driven mechanical load. Motor torque is a critical variable for instantaneous mechanical performance evaluation.

• Motor Speed: Provides real-time motor shaft rotation speed. When combined with torque, it offers a comprehensive snapshot of the rotating equipment’s mechanical performance.

• Motor Mechanical Load: Measures the actual mechanical power (displayed in hp or kW) produced by the motor. It provides a direct link to overload conditions without relying solely on motor current.

• Motor Efficiency: Indicates how effectively a motor converts electrical power into useful mechanical work. By aggregating this data across a facility, total efficiency can be estimated. Comparing this against expected efficiency helps calculate costs associated with energy inefficiency.

How It Works

Using proprietary algorithms, the Fluke 438-II Power Quality and Motor Analyzer utilizes three-phase current and voltage waveforms to calculate motor torque, speed, load, and efficiency at a 1-second update rate. The motor’s air-gap field, observed through voltage/current waveforms, serves as the basis for measurement. This eliminates the need for intrusive mechanical sensors or no-load motor testing, making analysis faster than ever.

Motor Types

The Fluke 438-II is compatible with:

• Direct-on-line (DOL) motors.

• Variable Frequency Drive (VFD) driven motors.

  • VFD Requirements: Must be a voltage-controlled system with a 40 to 70 Hz frequency range and a 2.5 kHz to 20 kHz carrier range.