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438-II Power Quality and Motor Analyser (w/o FC WiFi SD Card)

The FLUKE 438 Power Quality & Motor Analyser designed to quickly & easily measure & analyses key electrical/mechanical performance parameters such as power, harmonics, unbalance, motor speed, torque & mechanical power without the need of mechanical sensors.

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  • Competitive quote
  • Expert technical advice/demos
  • Trusted aftercare support





If you spend £150+ you will receive a great FLUKE tool absolutely FREE! Call us on 01782 563030 Ends: 31/08/2024



FLUKE 438 Series II Power Quality Motor Analyser

This product is now obsolete. To find out more about the 1773 Three-Phase Power Quality Analyser (from the range which has superseded the 438-II) CLICK HERE.

The FLUKE 438 Power Quality and Motor Analyser is a muti-purpose test tool designed to improve troubleshooting on electric motors and minimise downtime. Whether you are in a process plant or discrete manufacturing, electric motors are critical to your operations success; the FLUKE 438 lets you quickly gage electrical performance, power quality and mechanical performance of industrial motors. Using three-phase electrical measurements on the input and motor rating plate data, the 438 calculates following without the need to install mechanical sensors:

  • Torque - most critical mechanical performance variable 
  • Speed
  • Load on the motor shaft
  • Overall efficiency
  • All this with a single tool and all while the motor running so you don‘t sacrifice uptime!

Power Quality issues such as unbalance and harmonics can cause motors to run hot, eventually stressing windings and accelerating failures. Motor failures lead to costly downtime, and the cost of waste associated with inefficient motors add up! When testing direct online motors you get to see both power quality information and mechanical performance data in the same test, with a single tool!

With an intuitive user interface, optimised current probes and ‘at a glance‘ motor statuses the FLUKE 438 gives you the motor troubleshooting information you need to make better maintenance decisions and keep your plant up and running!

▶ FLUKE 438-II Power Quality and Motor Analyser Product Overview:

Thumbnail for the FLUKE 438-II video

FLUKE 438 Key Features:

  • Measure key parameters on direct-on-line motors: Torque, RPM, mechanical power and motor efficiency
  • Perform dynamic motor analysis by plotting of motor derating factor against load (according to NEMA/IEC guidelines)
  • Calculate mechanical power and efficiency without the need of mechanical sensors, just connect to the input conductors and you‘re ready to go
  • Measure electrical power parameters:
    • Voltage
    • Current
    • Power
    • Apparent power
    • Power factor
    • Harmonic distortion / unbalance to identify characteristics that impact motor efficiency
  • Identify power quality issues:
    • Dips
    • Swells
    • Transients
    • Harmonics
    • Unbalance
  • PowerWave data technology captures fast RMS data, and shows half-cycle averages and waveforms to characterise electrical system dynamics (generator start-ups, UPS switching etc.)
  • Waveform capture function captures 100/120 cycles (50/60 Hz) of each event detected event, in all modes, without set-up
  • Automatic transient mode captures waveform data at 200 kS/s on all phases simultaneously up to 6 kV
  • FLUKE Connect compatible: View data locally on the instrument, via FLUKE Connect mobile app and PowerLog 430-II desktop software
  • Safety rated for industrial applications 600 V CAT IV/1000 V CAT III rated for use at the service entrance and downstream


FLUKE 438 Electrical motor analysis:

The FLUKE 438-II provides a complete breakdown of electrical parameters. Prior to beginning motor analysis, it’s recommended to make base line 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, results are summarised for electrical performance, mechanical performance and derating (according to NEMA recommendations). The FLUKE 438 has an easy to understand four-level colour severity scale which indicates motor performance in relation to the recommended electrical parameter levels including rated power, power factor, unbalance and harmonics.  For mechanical power the the FLUKE 438 instantly shows you 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.  With this feature you can easily measure machine performance during each operation cycle.  The NEMA derating screen is updated as the load and the 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 investment decisions.


What comes with the FLUKE 438?

  • FLUKE 438-II Power Quality and Motor Analyser
  • Test Lead Set
  • Battery
  • Power Adapter
  • 8GB SD Card
  • Soft Carry Case
  • CD with PowerLog 430-II Software and User Documentation

What extra accessories come with the FLUKE 438-II (non-BASIC version)?

  • 4 x FLUKE i430 Flexible Current Probes


Have an older Power Quality Analyser Model? - Why not upgrade?

FLUKE 434-II, 435-II and 437-II Power Quality Analyser users can add motor analysis capabilities to their existing units with the Fluke 438 II/MA Motor Analyser upgrade kit.

The FLUKE 438 is the ideal portable motor analysis test tool helping you 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.


Comparison Chart for: Fluke 438-II Power Quality and Motor Analyser (w/o FC WiFi SD Card)

Energy studies
Measure V, I, kW, Cos/DPF, kWhr
Measure min/max and avg values
10-day logging
Waste energy monetization
Basic harmonics study
THD measurement (V & I)
Harmonics 1 to 25 for V & I
Advanced harmonics study
Full harmonic spectrum
Power harmonics
Basic industrial PQ troubleshooting
Oscilloscope function
Voltage dips and swells
Advanced industrial PQ troubleshooting
Comprehensive logging capability
Advanced features
Mains signaling
Power wave
Event waveform capture
400 Hz
Shipboard power
Power inverter efficiency
Motor analysis
Speed, torque, mechanical power, efficiencyUpgrade AvailableUpgrade AvailableUpgrade Available
Wireless download
Fluke Connect app
CAT IV/600 V


Accessory Code Description Price (Ex VAT)
BP291 4800 mAh High Capacity Li-Ion Battery £404.00 ADD
C437-II Hard case 430 Series II with rollers £659.00 ADD
HH290 Hanging Hook ScopeMeter Series 190 II £91.00 ADD
I430-FLEXI-TFII-4P 6000A FLUKE 430 THIN FLEXI 61CM (24IN) 4 PACK £1,640.00 ADD
i5sPQ3 AC Current Clamp (5 A) 3-pack £1,534.00 ADD