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Fluke 1736 and 1738 Three-Phase Power Quality Loggers

Key features

The Fluke 1736 and 1738 Three-phase Power Quality Loggers are versatile, three-phase Fluke Connect-compatible power loggers for conducting energy, load and power quality studies.

  • Key measurements: Automatically capture and log voltage, current, power, harmonics and associated power quality values, and capture dips, swells, and inrush currents with event waveform snapshots and high-resolution RMS profiles
  • Convenient instrument powering: Power instrument directly from the measured circuit
  • Energy Analyze Plus application software: Download and analyze every detail of energy consumption and power quality state of health with our automated reporting and use the integrated power quality health summary to get an at-a-glance understanding of system health

Fluke 1736 and 1738 Three-Phase Power Quality Loggers

The Fluke 1736 and 1738 Three-Phase Power Loggers built with Fluke Connect® mobile app and desktop software compatibility give you the data you need to make critical power quality and energy decisions in real-time. The ideal test tools for conducting energy studies and basic power quality logging, the 1736 and 1738 automatically capture and log over 500 power quality parameters so you have more visibility into the data you need to optimize system reliability and savings. With the Fluke 1738 Advanced Power Logger you can perform advanced analysis with an enhanced Power Quality Health Summary (EN50160) function that provides you with fast insight into overall electrical system health. The Power Quality Health Summary is an evaluation of the logged data based on detailed power quality measurements and includes viewable event waveform captures so you have even more visibility into the data you need to optimize system reliability and savings.

An optimized user interface, flexible current probes, and an intelligent measurement verification function that allows you to reduce measurement errors by digitally verifying and correcting common connection errors makes setup easier than ever and reduces measurement uncertainty. Access and share data remotely with your team via the Fluke Connect® app so you can maintain safer working distances and make critical decisions in real-time, reducing the need for protective equipment, site visits and check-ins. You can also quickly and easily chart and graph measurements to help identify issues and create detailed reports with the included Fluke Energy Analyze Plus software package. Optionally, you can create IEEE519 Reports giving you more insight into harmonic levels, voltage and current distortion, and load current (license required).

Other useful features:

  • Present data locally on the logger, on the Fluke Connect mobile app and desktop software, or through your facility’s Wi-Fi infrastructure
  • Measure all three phases and neutral with four flexible current probes (included)
  • Power the instrument directly from the measured circuit
  • Review measured values during logging sessions and before downloading for real-time analysis
  • Includes event waveform snapshot and high-resolution RMS profile with the 1738, along with date, timestamp and severity to capture dips, swells, and inrush currents and help pinpoint potential root causes of power quality issues
  • 1738 also provides fast insight into overall electrical system health with a Power Quality Health Summary
  • Offers a bright, color touch-screen display for convenient field analysis and data checks
  • Helps you capture the right data every time with a quick, guided, graphical user interface
  • Reduces uncertainty about your connections with the intelligent verification function
  • Allows you to complete field setups through the front panel or the Fluke Connect App on your smartphone
  • Provides fully integrated logging with other Fluke Connect-enabled devices to simultaneously log up to two additional measurement parameters on a Fluke Connect wireless digital multimeter or module*
  • Comes with Energy Analyze Plus application software that enables you to analyze every detail of energy consumption and power quality health and create automated reports


Log the most common parameters

Designed to measure the most critical three phase power parameters, the 1736 and 1738 can simultaneously log rms voltage, rms current, voltage and current events, voltage and current THD, voltage and current harmonics up to the 50th harmonic, active power, reactive power, power factor, active energy, reactive energy, and more. With enough memory for more than a year of data logging, the 1736 and 1738 can uncover intermittent or hard-to-find issues that might otherwise have been missed.

Analysis and Reporting

Capturing logged data is just one part of the task. Once you have the data, you need to create useful information and reports that can be easily shared and understood by your organization or customers. Fluke Energy Analyze Plus software makes that task as simple as possible. With powerful analysis tools and the ability to create customized reports in minutes you’ll be able to communicate your findings and quickly solve problems so you can optimize system reliability and savings.


Parameter Range Resolution Intrinsic Accuracy at Reference Conditions (% of Reading +% of Full Scale)
Voltage 1000 V 0.1 V ±(0.2% + 0.01%)
Current: Direct input
i17xx-flex 1500 12″
150 A 0.1 A ±(1% + 0.02%)
1500 A 1 A ±(1% + 0.02%)
i17xx-flex 3000 24″
300 A 1 A ±(1% + 0.03%)
3000 A 10 A ±(1% + 0.03%)
i17xx-flex 6000 36″
600 A 1 A ±(1.5% + 0.03%)
6000 A 10 A ±(1.5% + 0.03%)
i40s-EL clamp
4 A 1 mA ±(0.7% + 0.02%)
40 A 10 mA ±(0.7% + 0.02%)
Frequency 42.5 Hz to 69 Hz 0.01 Hz ±(0.1%)
Auxillary input ±10 V dc 0.1 mV ±(0.2% + 0.02%)
Voltage min/max 1000 V 0.1 V ±(1% + 0.1%)
Current min/max Defined by accessory Defined by accessory ±(5% + 0.2%)
THD on voltage 10 0.001 ±0.5
THD on current 10 0.001 ±0.5
Voltage harmonics 2nd to 50th
1000 V
0.1 V
≥ 10 V: ±5% of reading
< 10 V: ±0.5V
Current harmonics 2nd to 50th
Defined by accessory
Defined by accessory
≥ 3% of current range: ±5% of reading
< 3% of current range: ±0.15% of range
Unbalance 1 0.001 ±0.2


Intrinsic Uncertainty ±(% of reading +% of range)¹
Influence quantity
iFlex1500-12 iFlex3000-24 iFlex6000-36 i40S-EL
150 A / 1500 A 300 A / 3000 A 600 A / 6000 A 4 A / 40 A
Active Power P PF ≥ 0.99 1.2% + 0.005% 1.2% + 0.0075% 1.7% + 0.0075% 1.2% + 0.005%
Active Energy Ea PF ≥ 0.99 1.2% + 0.005% 1.2% + 0.0075% 1.7% + 0.0075% 1.2% + 0.005%
Apparent power S 0 ≤ PF ≤ 1 1.2% + 0.005% 1.2% + 0.0075% 1.7% + 0.0075% 1.2% + 0.005%
Apparent Energy Eap 0 ≤ PF ≤ 1 1.2% + 0.005% 1.2% + 0.0075% 1.7% + 0.0075% 1.2% + 0.005%
Reactive power Q 0 ≤ PF ≤ 1 2.5% of measured apparent power
Reactive Energy Er 0 ≤ PF ≤ 1 2.5% of measured apparent power
Power Factor PF ±0.025
Displacement Power Factor ±0.025
DBF/cosϕ ±0.025
Additional uncertainty in% of range¹ VP-N>250 V 0.00015 0.000225 0.000225 0.00015
¹Range = 1000 V x Irange
Reference conditions:Environmental: 23 °C ±5 °C, instrument operating for at least 30 minutes, no external electrical/magnetic field, RH <65%
Input conditions: Cosϕ/PF=1, Sinusoidal signal f=50 Hz/60 Hz, power supply 120 V/230 V ±10%.
Current and power specifications: Input voltage 1 ph: 120 V/230 V or 3 ph wye/delta: 230 V/400 V Input current: I > 10% of Irange
Primary conductor of clamps or Rogowski coil in center position
Temperature coefficient: Add 0.1 x specified accuracy for each degree C above 28 °C or below 18 °C


Electrical Specifications
Power Supply
Voltage range
100 V to 500 V using safety plug input when powering from the measurement circuit
100 V to 240 V using standard power cord (IEC 60320 C7)
Power consumption Maximum 50 VA (max. 15 VA when powered using IEC 60320 input)
Efficiency ≥ 68.2% (in accordance with energy efficiency regulations)
Maximum no-load consumption < 0.3 W only when powered using IEC 60320 input
Mains power frequency 50/60 Hz ±15%
Battery Li-ion 3.7 V, 9.25 Wh, customer-replaceable
On-battery runtime Four hours in standard operating mode, up to 5.5 hours in power saving mode
Charging time < 6 hours
Data Acquisition
Resolution 16-bit synchronous sampling
Sampling frequency
10.24 kHz at 50/60 Hz, synchronized to mains frequency
Input signal frequency
50/60 Hz (42.5 to 69 Hz)
Circuit types
1-φ, 1-φ IT, Split phase, 3-φ delta, 3-φ wye, 3-φ wye IT, 3-φ wye balanced, 3-φ Aron/Blondel (2-element delta), 3-φ delta open leg, Currents only (load studies)
Data storage
Internal flash memory (not user replaceable)
Memory size
Typical 10 logging sessions of 8 weeks with 1-minute intervals and 500 events¹
¹The number of possible logging sessions and logging period depends on user requirements.
Basic Interval
Measured parameters Voltage, current, aux, frequency, THD V, THD A, power, power factor, fundamental power, DPF, energy
Averaging interval User selectable: 1 sec, 5 sec, 10 sec, 30 sec, 1 min, 5 min, 10 min, 15 min, 30 min
Averaging time min/max values
Voltage, Current: Full cycle RMS updated every half cycle (URMS1/2 according to IEC61000-4-30 Aux, Power: 200ms
Demand Interval (Energy Meter Mode)
Measured parameters
Energy (Wh, varh, VAh), PF, maximum demand, cost of energy
User selectable: 5 min, 10 min, 15 min, 20 min, 30 min, off
Power Quality Measurements
Measured parameter Voltage, frequency, unbalance, voltage harmonics, THD V, current, harmonics, THD A, TDD
Averaging interval 10 min
Individual harmonics 2nd to 50th harmonic
Total harmonic distortion Calculated on 50 harmonics
Voltage: dips, swells, interruptions, current: inrush current
Triggered recordings
Full cycle RMS updated every half cycle of voltage and current (Urms1/2 according to IEC61000-4-30)
Waveform of voltage and current (1738)
Standards Compliance
IEC 61000-4-7: Class 1
IEEE 519 (short time harmonics)
Power quality
IEC 61000-4-30 Class S, IEC62586-1 (PQI-S device)
Power IEEE 1459
Power quality compliance
EN50160 (for measured parameters)
File transfer via USB flash drive, firmware updates
Max. current: 120 mA
File transfer and remote control via direct connection or WiFi infrastructure
Read auxiliary measurement data from Fluke Connect® 3000 series modules (requires 1738 or 1736 upgrade option)
Data download device to PC
Voltage Inputs
Number of inputs
4 (3 phases and neutral)
Maximum input voltage
1000 Vrms, CF 1.7
Input impedance 10 MΩ
Bandwidth (-3 dB)
42.5 Hz – 3.5 kHz
Scaling 1:1 and variable
Measurement category
1000 V CAT III/600 V CAT IV
Current Inputs
Number of inputs
4, mode selected automatically for attached sensor
Input voltage
Clamp input: 500 mVrms/50 mVrms; CF 2.8
Rogowski coil input
150 mVrms/15 mVrms at 50 Hz, 180 mVrms/18 mVrms at 60 Hz; CF 4; all at nominal probe range
1 A to 150 A/10 A to 1500 A with thin flexible current probe i17XX-flex1500 12″
3 A to 300 A/30 A to 3000 A with thin flexible current probe i17XX-flex3000 24″
6 A to 600 A/60 A to 6000 A with thin flexible current probe i17XX-flex6000 36″
40 mA to 4 A/0.4 A to 40 A with 40 A clamp i40s-EL
Bandwidth (-3 dB)
42.5 Hz – 3.5 kHz
Scaling 1:1 and variable
Auxiliary Inputs
Number of inputs 2
Input range
0 to ±10 V dc, 1reading/s
Scale factor
Format: mx + b (gain and offset) user configurable
Displayed units
User configurable (7 characters, for example, °C, psi, or m/s)
Wireless Connection
Number of inputs 2
Supported modules
Fluke Connect® 3000 series
Acquisition 1 reading/s
Environmental Specifications
Operating temperature
-10 °C to +50 °C (14 °F to 122 °F)
Storage temperature
-20 °C to +60 °C (-4 °F to 140 °F), with battery: -20 °C to +50 °C (-4 °F to 122 °F)
Operating humidity
10 °C to 30 °C (50 °F to 86 °F) max. 95% RH
30 °C to 40 °C (86 °F to 104 °F) max. 75% RH
40 °C to 50 °C (104 °F to 122 °F) max. 45% RH
Operating altitude
2000 m (up to 4000 m derate to 1000 V CAT II/600 V CAT III/300 V CAT IV)
Storage altitude 12,000m
IP50 in accordance with EN60529
MIL-T-28800E, Type 3, Class III, Style B
IEC 61010-1
IEC Mains Input: Overvoltage Category II, Pollution Degree 2
Voltage Terminals: Overvoltage Category IV, Pollution Degree 2
IEC 61010-2-031: CAT IV 600 V / CAT III 1000 V
Electromagnetic compatibility
EN 61326-1: Industrial CISPR 11: Group 1, Class A
Korea (KCC): Class A Equipment (industrial broadcasting and communication equipment)
USA (FCC): 47 CFR 15 subpart B. This product is considered an exempt device per clause 15.103
Temperature coefficient
0.1 x accuracy specification/°C
General Specifications
Color LCD display
4.3-inch active matrix TFT, 480 pixels x 272 pixels, resistive touch panel
Instrument and power supply: Two-years (battery not included)
Accessories: one-year
Calibration cycle: two-years
Instrument: 19.8 cm x 16.7 cm x 5.5 cm (7.8 in x 6.6 in x 2.2 in)
Power supply: 13.0 cm x 13.0 cm x 4.5 cm (5.1 in x 5.1 in x 1.8 in)
Instrument with power supply attached: 19.8 cm x 16.7 cm x 9 cm (7.8 in x 6.6 in x 3.5 in)
Instrument: 1.1 kg (2.5 lb)
Power supply: 400 g (0.9 lb)
Tamper protection
Kensington lock slot
i17xx-flex 1500 12″ Flexible Current Probe Specifications
Measuring range
1 to 150 A ac/10 to 1500 A ac
Nondestructive current
100 kA (50/60 Hz)
Intrinsic error at reference condition*
±0.7% of reading
Accuracy 173x + iFlex
±(1% of reading + 0.02% of range)
Temperature coefficient over operating temperature range
0.05% of reading/°C 0.09% of reading/°F
Working voltage
1000 V CAT III, 600 V CAT IV
Probe cable length 305 mm (12 in)
Probe cable diameter 7.5 mm (0.3 in)
Minimum bending radius 38 mm (1.5 in)
Output cable length 2 m (6.6 ft)
Weight 115 g
Probe cable material TPR
Coupling material POM + ABS/PC
Output cable TPR/PVC
Operating temperature
-20 °C to +70 °C (-4 °F to 158 °F) temperature of conductor under test shall not exceed 80 °C (176 °F)
Temperature, non-operating
-40 °C to +80 °C (-40 °F to 176 °F)
Relative humidity, operating
15% to 85% non-condensing
IP rating IEC 60529:IP50
Warranty One-year
* Reference condition:Environmental: 23 °C ±5 °C, no external electrical/magnetic field, RH 65%
Primary conductor in center position