Fluke 438-II Power Quality Analyzer & Motor Analyzer

Product By Flir Logo

Quickly and easily discover electrical and mechanical performance of electric motors, and evaluate power quality with a single test tool

The Fluke 438-II Power Quality and Motor Analyzer adds key mechanical measurement capabilities for electric motors to the advanced power quality analysis functions of the Fluke 435 Series II Power Quality Analyzers. 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. Fluke 434-II, 435-II and 437-II Power Quality Analyzer users can add motor analysis capabilities to their existing units with the Fluke-438-II/MA Motor Analyzer upgrade kit. The 438-II uses data from the motor rating plate for either NEMA or IEC rated motors to aid the calculation of the mechanical parameters.

Other useful features:

  • Calculates mechanical power and efficiency without mechanical sensors. Just connect to the input conductors
  • Measures 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
  • Uses PowerWave data capture to capture fast RMS data, and show half-cycle averages and waveforms to characterize electrical system dynamics (generator start-ups, UPS switching etc.)
  • Offers waveform capture function to capture 100/120 cycles (50/60 Hz) of each detected event, in all modes, without set-up
  • Uses automatic transient mode to capture waveform data at 200 kS/s on all phases simultaneously up to 6 kV
  • Automatically calculate motor derating according to NEMA/IEC guidelines
  • Fluke Connect® compatible so you can view data locally on the instrument, via Fluke Connect mobile app and PowerLog 430-II desktop software
Drive Measurement Details
Motor Type3 phase asynchronous (induction)
Power SourceVariable Frequency Drive
Motor Frequency Range40Hz to 70Hz
Over/Under Voltage from Nominal V/f Curve (%)-15% to +15%
Carrier Frequency Range2.5kHz–20kHz
Variable speed drive technology that is covered by the 438-II
Inverter TypeVSI only (voltage controlled) *
Control MethodV/f control, open-loop vector, closed loop vector, drives with encoders.
Frequency40 to 70 Hz
* VSI drives are the most common drives. The alternative CSI drives are used in higher power applications.
Variable speed drive technology NOT covered by the 438-II
Inverter TypeCSI (current source inverter)
Motors typeSynchronous (DC, stepper, permanent magnet etc.)
Motor Frequency<40 and >70 Hz
Mechanical specifications
Mechanical measurements can be performed on direct online motors with a 3 wire connection.
Motor measurement
 RangeResolutionAccuracyDefault limit
Mechanical motor

0.7 kW to 746 kW

1 hp to 1000 hp
0.1 kW

0.1 hp
±3% 1

±3% 1
100% = rated power

100% = rated power
Torque0 Nm to 10 000 Nm

0 lb ft to 10 000 lb ft
0.1 Nm

0.1 lb ft
±5% 1

±5% 1
100% = rated torque

100% = rated torque
rpm0 rpm to 3600 rpm1 rpm±3% 1100% = rated rpm
Efficiency0% to 100%0.10%±3% 1NA
Unbalance (NEMA)0% to 100%0.10%±0.15%5%
Harmonics Voltage
Factor (NEMA)
0 to 0.200.1±1.5%0.15
Unbalance Derating
0.7 to 1.00.1indicativeNA
Harmonics Derating
0.7 to 1.00.1indicativeNA
Total NEMA Derating
0.5 to 1.00.1indicativeNA
Notes:Supports motor design types NEMA A, B, C, D & E and IEC type H and N.
Rated torque is calculated from rated power and rated speed.
Update rate of Motor Measurements is 1x per second.
Default Trend duration is 1 week.
1Add 5% error when selecting Motor design type Other
Specification valid for Motor Power > 30% of rated power
Specification valid at stable operating temperature. Run the motor for at least 1 hour at full load
(2-3 hours if the motor is 50 HP or higher) to obtain stable temperature
Product Specifications
VoltModelMeasurement RangeResolutionAccuracy
Vrms (AC + DC) 1 V to 1000 V phase to neutral0.01 V±0.1% of nominal voltage 1
Vpk 1 Vpk to 1400 Vpk1 V5% of nominal voltage
Voltage Crest Factor (CF) 1.0 > 2.80.01±5%
Vrms½  0.1 V±0.2% of nominal voltage
Vfund  0.1 V±0.1% of nominal voltage
Amps (AC + DC)i430-Flex 1x 5 A to 6000 A1 A±0.5% ±5 counts
i430-Flex 10x0.5 A to 600 A0.1 A±0.5% ±5 counts
1mV/A 1x5 A to 2000 A1A±0.5% ±5 counts
1mV/A 10x0.5 A A to 200 A (AC only)0.1 A±0.5% ±5 counts
Apki430-Flex8400 Apk1 Arms±5%
1mV/A5500 Apk1 Arms±5%
A Crest Factor (CF) 1 to 100.01±5%
Amps½i430-Flex 1x5 A to 6000 A1 A±1% ±10 counts
i430-Flex 10x0.5 A to 600 A0.1 A±1% ±10 counts
1mV/A 1x5 A to 2000 A1 A±1% ±10 counts
1mV/A 10x0.5 A A to 200 A (AC only)0.1 A±1% ±10 counts
Afundi430-Flex 1x5 A to 6000 A1 A±0.5% ±5 counts
i430-Flex 10x0.5 A to 600 A0.1 A±0.5% ±5 counts
1mV/A 1x5 A to 2000 A1 A±0.5% ±5 counts
1mV/A 10x0.5 A A to 200 A (AC only)0.1 A±0.5% ±5 counts
Fluke 434 @ 50 Hz Nominal42.50 Hz to 57.50 Hz0.01 Hz±0.01 Hz
Fluke 434 @ 60 Hz Nominal51.00 Hz to 69.00 Hz0.01 Hz±0.01 Hz
Watts (VA, var)i430-Flexmax 6000 MW0.1 W to 1 MW±1% ±10 counts
1 mV/Amax 2000 MW0.1 W to 1 MW±1% ±10 counts
Power Factor (Cos j/DPF)0 to 10.001±0.1% @ nominal load conditions
kWh (kVAh, kvarh)i430-Flex 10xDepends on clamp scaling and V nominal±1% ±10 counts
Energy Lossi430-Flex 10xDepends on clamp scaling and V nominal±1% ±10 counts Excluding line resistance accuracy
Harmonic Order (n)DC, 1 to 50 Grouping: Harmonic groups according to IEC 61000-4-7
Inter-Harmonic Order (n)OFF, 1 to 50 Grouping: Harmonic and Interharmonic subgroups according to IEC 61000-4-7
Volts %f0.0% to 100%0.1%±0.1% ±n x 0.1%
r0.0% to 100%0.1%±0.1% ±n x 0.4%
Absolute0.0 to 1000 V0.1 V±5% 1
THD0.0% to 100%0.1%±2.5%
Amps %f0.0% to 100%0.1%±0.1% ±n x 0.1%
r0.0% to 100%0.1%±0.1% ±n x 0.4%
Absolute0.0 to 600 A0.1 A±5% ±5 counts
THD0.0% to 100%0.1%±2.5%
Watts %f or r0.0% to 100%0.1%±n x 2%
AbsoluteDepends on clamp scaling and V nominal±5% ±n x 2% ±10 counts
THD0.0% to 100%0.1%±5%
Phase Angle-360° to +0°±n x 1°
Plt, Pst, Pst (1 min) Pinst0.00 to 20.000.01±5%
Volts %0.0% to 20.0%0.1%±0.1%
Amps %0.0% to 20.0%0.1%±1%
Mains Signaling
Threshold LevelsThreshold, limits and signaling duration is programable for two signaling frequencies
Signaling Frequency60 Hz to 3000 Hz0.1 Hz 
Relative V %0% to 100%0.10%±0.4%
Absolute V3s (3 second avg.)0.0 V to 1000 V0.1 V±5% of nominal voltage
General Specifications
CaseDesign Rugged, shock proof with integrated protective holster Drip and dust proof IP51 according to IEC60529 when used in tilt stand position Shock and vibration Shock 30 g, vibration: 3 g sinusoid, random 0.03 g 2 /Hz according to MIL-PRF-28800F Class 2
DisplayBrightness: 200 cd/m 2 typ. using power adapter, 90 cd/m 2 typical using battery power Size: 127 x 88 mm (153 mm/6.0 in diagonal) LCD Resolution: 320 x 240 pixels Contrast and brightness: user-adjustable, temperature compensated
Memory16GB Wi-Fi SD card for standard models or 8GB SD card for /INTL models (SDHC compliant, FAT32 formatted), up to 32GB optionally. Screen save and multiple data memories for storing data including recordings (dependent on memory size).
Real-Time ClockTime and date stamp for Trend mode, Transient display, System Monitor and event capture
Operating Temperature0°C ~ +40°C; +40°C ~ +50°C excl. battery
Storage Temperature-20°C ~ +60°C
Humidity+10°C ~ +30°C: 95% RH non-condensing
+30°C ~ +40°C: 75% RH non-condensing
+40°C ~ +50°C: 45% RH non-condensing
Maximum Operating AltitudeUp to 2,000 m (6666 ft) for CAT IV 600 V, CAT III 1000 V
Up to 3,000 m (10,000 ft) for CAT III 600 V, CAT II 1000 V
Maximum storage altitude 12 km (40,000 ft)
Electro-Magnetic-Compatibility (EMC)EN 61326 (2005-12) for emission and immunity
InterfacesMini-USB-B, Isolated USB port for PC connectivity SD card slot accessible behind instrument battery
WarrantyThree years (parts and labor) on main instrument, one year on accessories
View full family specifications »
1. ±5% if ? 1% of nominal voltage ±0.05% of nominal voltage if < 1% of nominal voltage
2. 50Hz/60Hz nominal frequency according to IEC 61000-4-30
3. 400Hz measurements are not supported for Flicker, Mains Signaling and Monitor Mode
4. For nominal voltage 50 V to 500 V