438 Power Quality and Motor Analyser

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.

Part Number:
Fluke 438-II/BASIC

read more


Product Options

List Price:

7296.00 incl. VAT)
Add To Cart



The Fluke 438 Power Quality and Motor Analyser is a muti-purpose test tool designed to improve trouble shooting on electric motors and minimise down-time.

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, with the 438, you get 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 status screens the Fluke 438 gives to you the motor troubleshooting information you need to make better maintenance decisions and keep your plant up and running!

Key Features:

  • Measure key parameters on direct-on-line motors including 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 such as voltage, current, power, apparent power, power factor, harmonic distortion and unbalance to identify characteristics that impact motor efficiency
  • Identify power quality issues such as dips, swells, transients, harmonics and unbalance
  • PowerWave data technology captures fast RMS data, and shows half-cycle averages and waveforms to characterize 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

Further reading on the 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 “+”. In this example we can see that motor is within tolerance but is  close to the service factor. This indicates that there may be a need for power quality mitigation, motor maintenance or some other performance improving adjustment. By frequently performing these tests over time, known benchmarks and performance trends can be created, enabling informed maintenance investment decisions.

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.


Technical Specification for: Fluke 438 Power Quality and Motor Analyser

Product Downloads


Accessory Code Description Price (Ex VAT)
BP291 Battery Pack Fluke 190 Series (Li-ION Double Capacity) £300.00 ADD
C1740 Softcase for 174X and 43X-II PQ analyzer £207.00 ADD
C437-II Hard case 430 Series II with rollers £476.00 ADD
FLK-FC_SD Card Connect Wireless SD Card £99.00 ADD
HH290 Hanging Hook ScopeMeter Series 190 II £67.00 ADD
i430-Flexi-TF-II-4PK 6000A FLUKE 430 THIN FLEXI 61CM (24IN) 4 PACK £1,184.00 ADD
i5sPQ3 AC Current Clamp (5 A) 3-pack £1,140.00 ADD


Product Training 1/2 Day more info
Product Awareness Course

Get to know your new purchase! Maximise your return on investment with product and software training modules!

A lack of product training can result in under-utilisation of test equipment, low return on investment and, most importantly, incorrect use.

Product Training 1 Day more info
Product Awareness Course

Get to know your new purchase! Maximise your return on investment with product and software training modules!

A lack of product training can result in under-utilisation of test equipment, low return on investment and, most importantly, incorrect use.

We remain operational for Test Instrument Sales, Calibration, Servicing and Repair.

We are open and here to help support your business.

For more information click here

COVID-19: We're Open & Operational