Fluke 438-II

The Fluke 438-II Three-Phase Power Quality and Motor Analyzer with iFlex Probes allows you to quickly and easily measure and analyze key electrical and mechanical performance parameters such as power, harmonics, unbalance, motor speed, torque and mechanical power without the need of mechanical sensors.

The ideal portable motor analysis test tool, the 438-II can help locate, predict, prevent, and troubleshoot power quality problems in three-phase and single-phase power distribution systems, while giving technicians the mechanical and electrical information they need to effectively evaluate motor performance.

Motor Torque

With the 438-II you can calculate the amount of rotational force (displayed in lb.ft or Nm) developed by a motor and being transmitted to a driven mechanical load. The motor torque is the single most critical variable that characterizes the instantaneous mechanical performance of rotating equipment driven by electric motors.

Motor Speed

This tool can also provide the instantaneous motor shaft rotational speed. Combined with the motor torque, motor speed is a snapshot of the mechanical performance of rotating equipment driven by electric motors.

Motor Mechanical Load

The 438-II measures the actual mechanical power (displayed in hp or kW) produced by motors and provides a direct link to overloading conditions without simply basing it on the motor current.

Motor Efficiency

Show the effectiveness of each motor within a machine, assembly line, plant, and facility in converting electric power to useful mechanical work with the 438-II analyzer. By properly aggregating the efficiencies of a population of motors the total (aggregate) efficiency can be estimated. Comparisons to expected motor efficiencies at observed operating conditions can help quantify the cost associated with motor energy inefficiency.

How it Works

Using proprietary algorithms, the 438-II uses three-phase current and voltage waveforms to calculate motor torque, speed, load and efficiency at a 1 second update rate. The motor air gap field, as observed via the voltage/current waveforms, provides the basis for the measurements. Mechanical sensors and intrusive no-load motor testing is not required, making it faster than ever to analyze overall electric motor performance.

Electrical Motor Analysis

This tool provides a complete breakdown of electrical parameters. Prior to beginning motor analysis, it is recommended to make baseline power quality measurements to assess the state of harmonics and unbalance on the electrical service output, as these two properties can have a serious, negative impact on motor performance. When in Motor Analysis mode, the results are summarized for electrical performance, mechanical performance and derating (according to NEMA recommendations). The easy-to-understand four-level color severity scale indicates motor performance in relation to the recommended electrical parameter levels, including rated power, power factor, unbalance and harmonics.

With this feature, you can instantly view the mechanical output power, along with motor torque and speed. The mechanical output power is instantly compared with electrical power to provide you with live efficiency measurements, making it easy to measure machine performance during each operation cycle.

The NEMA derating screen is updated as the load and electrical conditions change, and each new measurement is plotted on the tolerance graph as a "+". By frequently performing these tests over time, known benchmarks and performance trends can be created, enabling informed maintenance and investment decisions.