### 38. **Understanding Power Calibration**

- APP038 answers all of the common questions we receive from customers regarding calibration. It also addresses many misunderstood aspects of the calibration process.

APP038 – Understanding Power Calibration (PDF, 438KB)

### 37. Do I need a power analyzer or can I use a DAQ card?

- APP037 provides a thorough overview of why dedicated Power Analyzers offer far greater accuracy performance for power measurement than a Data Acquisition Card(DAQ) based system. The signal chain of each approach is reviewed in detail and reasons for selecting a dedicated power analyzer for your power measurements become clear.

APP037 – Do I need a power analyzer or can I use a DAQ card (PDF, 425KB)

### 36. 6 & 7 Phase Motor Drive Analysis

- APP036 describes a new algorithm developed for the PPA3500 precision power analyzer which enables 7 phase power measurement utilizing only 6 wattmeters. With the new “7 Phase” mode the engineer is able to obtain true 3 phase measurements when connected in a 3 Phase 2 wattmeter wiring configuration. Previously, only SUM parameters were able to be determined when connected in a 3 phase 2 wattmeter configuration – these restrictions no longer apply.

APP036 – 6 & 7 Phase Motor Drive Analysis (PDF, 203KB)

### 35. Low Power Factor Watts Measurement & Calibration

- APP035 in this application note, we will discuss the subject of low power factor power measurements and explain the significance of some specification formats from calibration that can be misleading.

APP035 – Low Power Factor Power Measurement (PDF, 228KB)

### 34. Flicker Simulation with the N4A AC Power Sources

- APP034 describes how to generate flicker simulation wave forms in order to test flicker meters for their operation as well as simulate environments exhibiting flicker for the testing of DUT’s(devices under test)

APP034 – Flicker Simulation with the N4Axx AC Power Sources (PDF, 156KB)

### 33. Battery Cell Electrochemical Impedance Spectroscopy (PSM3750+BATT470m)

- APP033 introduces electrochemical impedance spectroscopy (EIS) and its application to impedance measurement of batteries/cells. The BATT470m current shunt provides a simple interface connection and reliable, accurate measurements up to 100V.

APP033 – Battery Cell Electrochemical Impedance Spectroscopy (PDF, 394KB)

### 32. Efficiency Measurement of Traction Motors

- This article will discuss the important aspects of efficiency measurement that a Power Analyzer will need to address when undertaking measurements of a DC-AC converter, as part of the EV traction system development process.

APP032 – Efficiency Measurement of Traction Motors (PDF, 274KB)

### 31. Expanded Nyquist Sampling Theory

- In this guide, we will explain a technique developed by N4L that overcomes a problem faced by most digital sampling measurement instruments and in making this process clear, we hope to dispel some commonly held misconceptions regarding digital sampling theory.

APP031 – Expanded Nyquist Sampling Theory – N4L (PDF, 44KB)

### 30. DFT or FFT? A Comparison of Fourier Transform Techniques

- The Discrete Fourier Transform(DFT) is a demanding algorithm, APP030 investigates the benefits of the DFT and why N4L do not utilise the FFT for harmonic analysis.

APP030 – DFT or FFT – A Comparison of Fourier Transform Techniques (PDF, 372KB)

### 29. Capacitor Analysis with High DC Bias Voltage

- In this application note , a PSM1700 Frequency Response analyzer, LPA400 Power amplifier and a HF01A Current shunt are used to analyze the capacitance of a 1uF capacitor whilst subjected to varying DC bias voltages.

APP029 – Capacitor Impedance Measurements with High DC Voltage Biasing (PDF, 179KB)

### 28. N4L Harmonics and Flicker Compliance Verification of PPA55xx to IEC61000-3-2, IEC61000-3-3, IEC61000-3-11, IEC61000-3-12

- This application note discusses measurements made with PPA5500 family of precision power analysers from Newtons4th Ltd in order to verify the performance of the analyser in a test system fully compliant to the relevant standards.

APP028 – N4L Harmonics and Flicker Compliance Verification of PPA55xx to IEC61000-3-2, 3-3, 3-11 & 3-12 (PDF, 179KB)

### 26. IEC61000-3-3 2013 Electromagnetic Compatability – A guide to Flicker Measurement

- N4L provide ISO17025 UKAS Accredited Flickermeters, this application note discusses what flicker is and the field of flicker measurement.

APP026 – IEC61000-3-3 2013 Electromagnetic Compatability – A Technical Guide to Flicker Measurement (PDF, 800KB)

### 25. PWM Motor Drive Ramp Testing with the PPA45/5500 Power Analyzers

- This application note discusses the setup and analysis of PWM Inverter Motor Drives, specifically when rapid fundamental frequency and load change is likely.

APP025 – PWM Motor Drive Ramp Testing with the PPA45_5500 Power Analyzers (PDF, 153KB)

### 24. Sweep Frequency Response Analysis of Power Transformers – Typical Test Sequences (IEC60076-18)

- In this application note we discuss the mathematics behind harmonics analysis.

APP024 – Sweep Frequency Response Analysis of Power Transformers – Typical Test Sequences IEC60076-18 (PDF, 164KB)

### 23. Harmonic Analysis in Power Applications

- In this application note we discuss the mathematics behind harmonics analysis.

APP023 – Harmonic Analysis in Power Applications (PDF, 67.2KB)

### 22. PSRR(Power Supply Rejection Ratio) Testing

- Power Supply Rejection Ratio (PSRR) analysis present the engineer with numerous measurement challenges, specifically the task of perturbation signal injection. This application note describes the approach to such a measurement utilising the PSM3750 Frequency Response Analyser and an injection inductor.

APP022 – PSRR – Power Supply Rejection Ratio Testing (PDF, 390KB)

### 21. Master Slave Efficiency Testing

- In this application note we delve into the world of efficiency testing and take a look at the downfalls intruments using gapped measurement techniques suffer from. We describe the N4L approach to such testing and reasons why we offer more reliable and more accurate measurements than those possible with traditional techniques.

APP021 -Master Slave Effieicency testing (PDF, 160KB)

### 20. Amplifier Frequency Response

- This application note discusses frequency response analysis of a power amplifier including a detailed guide describing the set up of the PSM1735 frequency response analyzer.

APP020 – Amplifier Frequency Response (PDF, 160KB)

### 19. RMS and Peak range consideration in Precision Power Analyzers

- This application note discusses RMS and Peak range considerations when analyzing modern power electronic waveforms. We look at both approaches and discuss why N4L’s measurement techniques offer superior data capture.

APP019 – RMS and Peak range considerations with Precision Power Analyzers (PDF, 175KB)

### 18. Transformer Efficiency testing and Transformer Vector Theory

- In this application note we discuss the losses in a transformer, how these losses effect the power factor on the primary and how the nature of the load on the secondary effects the power factor on the primary.

APP018 – Transformer Efficiency Testing and Transformer Vector Theory (PDF, 405KB)

### 17. PWM Motor Drives – Pulse Width Modulation Theory

- Pulse Width Modulation has become a common approach to motor control, this application note provides an introduction to the concept and discusses measurement considerations test and development engineers should consider when selecting test equipment.

APP017 – PWM Motor Drives – Pulse Width Modulation Theory (PDF, 810KB)

### 16. RFI Line Filter Testing – Frequency Response Analysis

- RFI or Radio Frequency Interference present at the input of equipment connected to the power line is filtered out with a line filter in order to prevent the unwanted interference in the radio frequency band disrupting the correct operation of electronic equipment. This application note will take the engineer through testing RFI Line filters with the PSM1735 Frequency Response Analyser.

APP016 -Testing RFI Line Filters – Frequency Response Analysis (PDF, 759KB)

### 15. Standby Power Testing – IEC62301

- This application note describes the challenges associated with standby power testing to IEC62301, it describes how Newtons4th’s power analyzers make stable, accurate measurements in this field. We also describe how to use our testing software and illustrate how simple it is to use.
- APP015 – Standby Power Measurement – IEC62301 (PDF, 2,183KB)

### 14. 3 Phase 2 Wattmeter Explained – Power Analysis

- 3 Phase 2 Wattmeter is a common configuration in use in the power measurement field, in this application note we explain the maths behind the measurements in order to understand how 2 wattmeters can measure power on 3 phases. Real Votlages and currents are used in order to make sense of the theory and we explore both balanced and unbalanced loads.

APP014 – 3 Phase 2 Wattmeter Explained (PDF, 663KB)

### 13. Efficiency Measurements of AC – DC Power supplies using the PPA1500 series Power Analyzers

- The PPA1500 series power analyzers (PPA1520 + PPA1530) have benefited from a firmware upgrade which has enabled the instrument to perform AC-DC power supply efficiency measurements. The PPA1500 series provides the engineer with an accurate, affordable and simple to setup the Power Analyzer, see our products section for more details. The PPA1500 series possess a high accuracy specification as a result of innovative analogue and digital design techniques, these also offer the engineer high performance at a lower price.

APP013 – AC – DC Efficiency Measurements with the PPA1520 (PDF, 255KB)

### 12. Unique N4L Current Shunt Design – Field Cancellation

- Newtons4th Ltd have developed a unique current shunt which incorporates excellent field cancellation characteristics whilst maintaining low manufacturing costs. This application note details the theory behind the design of the shunt and the importance of low inductance characteristics of current shunts in power analysis.

APP012 – Current Shunt Field Cancellation (PDF, 590KB)

### Control loop frequency response testing

- A 1 minute video sample which illustrates various display options available to a user of the PSM1700 when in Frequency Response Analysis mode.

In this example, the PSM1700 is testing the closed loop stability of a switched mode power supply when connected to the control loop of the supply via an injection resistor and an N4L injection transformer. Control loop frequency response testing

### 11. LCR Measurement of Components at High Frequency

- As frequencies increase over a few MHz, accurately measuring component impedance becomes progressively more difficult, this application note discusses best practices for such measurements.

APP011 Imp-at-high-freq Jan09 (PDF, 45KB)

### 10. Switched Mode Power Supply Loop gain measurement with multiple loops

- Where multiple loops exist in a power supply feedback path and cannot be isolated, it is not possible to directly measure the loop gain. In this case it is necessary to make measurements on each loop and combine the results mathematically.

APP010 Testing Switched Mode Power Supply Multiple Loop Gain (PDF, 23KB)

### 9. Power accuracy at specified frequency and phase angle

- The practical measurement of power is influenced by a number of factors which can introduce inaccuracies. Power analyzer manufacturers, including N4L, usually quote a simplified expression for power accuracy to allow computation of the realistic measurement uncertainty to be expected.

APP009 Power Accuracy (PDF, 64KB)

### 8. LCR measurements

- The PSM range can be used to measure the characteristics of inductors, capacitors and resistors under precise operating conditions. The two inputs are both voltage inputs so some external shunt arrangement is needed. By using an external shunt, the shunt can be optimised for the conditions of the test. The Active LCR head and Impedance Analysis Interface available as an accessory from N4L include a number of different high frequency shunts that can be selected from the instrument front panel. Alternatively, the circuit arrangements shown here can be used.

APP008 LCR measurements (PDF, 90KB)

### 7. Measuring low THD

- Amongst the many measurement modes of the PSM range there is a harmonic analyzer that can measure a single harmonic or can compute total harmonic distortion (THD) from a series of harmonics. The PSM range measures THD by simultaneous computing a DFT for each of the harmonics in the series up to the maximum number specified.

APP007 Measuring low THD (PDF, 23KB)

### 6. High voltage capacitance measurement

- Some high voltage devices have different characteristics at the lower voltages usually used to measure capacitance. The LPA400 can be used with the PSM2200 or PSM2201 to analyse devices at up to 800V pk-pk from dc to 100kHz and up to 80V pk-pk up to 1MHz. Measurements of capacitance, ac resistance, tan(θ), and even power can be made under controlled conditions that are representative of the real operating conditions for the device.

APP006 High voltage capacitance measurement (PDF, 23KB)

### 5. Measuring fluctuating signals

- The PSM range are real-time analysis instruments that simultaneously acquire and process data, once the input conditions are valid. The default set up conditions for the PSM range is most suitable for measuring steady state, or slowly fluctuating signals – for rapidly fluctuating signals there are three areas where the response of the instrument can be improved using the menus or the communication commands: 1. Input ranging; 2. Filtering; 3. Frequency determination.

APP005 Measuring fluctuating signals (PDF, 16KB)

### 4. Testing FSK communications

- FSK (frequency shift keying) is a well established technique for encoding binary data by transmitting one frequency for ‘zero’ and a different frequency for ‘one’. It is commonly used in industrial monitoring and control systems where transmitters and receivers may be separated by long distances. In order to have confidence in the communications, it is important to verify the signal levels at the receivers to detect any degradation in performance, such as would be caused by increased cable resistance or poor connectors.
- APP004 Testing FSKs (PDF, 11KB)

### 3. Using the PSM Series with LVDTs

- LVDTs (Linear Variable Differential Transformer) consist of a transformer with one primary winding, two secondary windings and a moveable armature. With the primary energised at a suitable frequency, the magnitude and relative phase of the secondaries change as the armature is moved. This document describes how the PSM2200 QuanteQ may be used to analyse such a system.

APP03 Testing LVDTs (PDF, 27KB)

### 2. Testing loop stability

- PSM units are ideally suited to measuring the gain/phase response of a control loop by injecting a small disturbance and analysing the results. The PSM range use DFT analysis (Discrete Fourier Transform) to measure the relative gain and phase of the signal round the loop at the specific test frequency, rejecting any other frequency components present (such as noise or ripple). The test frequency can be swept automatically over the desired frequency range and the results viewed on the screen or printed out…

View App note 002 | |

Online version | Link |

Pdf. Download | APP002 Testing loop stability (PDF, 66KB) |

### 1. Testing communications transformers

- PSM units are well suited to testing transformers either manually or automatically (using a PC). Using DFT and true rms measurements over a wide frequency range, PSM units used in conjunction with our transformer testing accessories perform most commonly required transformer tests.

View App note 001 | |

Online version | Link |

Pdf. Download | APP001 Testing communications transformers (PDF, 66KB) |