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
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
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
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.
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)
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.
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.
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.
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…
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.