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Bulk ceramic resistors vs film and wire-wound

Non-inductive bulk ceramic resistors are capable of handling extremes that film and wire wound resistors cannot. Ceramic technology offers the power range and non-inductive characteristics of film resistors but with overload and pulse energy capabilities that exceed the performance of wire-wound resistors – in a fraction of the footprint.

From soft-start and snubber circuits to dynamic braking and RF dummy loads, non-inductive bulk ceramic resistors have a wide range of applications, such as: radar, motor drives, broadcast transmitters, RF amplifiers, semiconductor process equipment, high voltage power supplies, switchgear, x-ray, lasers, medical defibrillators, and energy research. Electronic systems often require rugged resistors that perform reliably under conditions of high voltage, current, or energy.

Pulse, pre-charge and softstart

The compact pulse energy capability of ceramics allows flexible design without sacrificing power. Ceramic resistors can obtain greater power dissipation in one third of the footprint of wirewound resistors, delivering excellent performance where high peak power or high-energy pulses must be handled in small and efficient spaces.

Resistor technology comparison

Parameter Wire-wound Film Ceramic
Inductance (nH) 30-56000 2-200 2-200
Peak power Poor Poor Excellent
Overload Medium Poor Excellent
Pulsed energy Medium Poor Excellent
Geometry size Complex packaging Flexible Flexible
Power range 5 W to 1 kW 1 W to 1 kW 1 W to 1 kW

High Voltage

High voltage continuous and pulse applications can be addressed with ceramic resistors, including radar, x-ray, defibrillators, lasers, broadcast transmitters and semiconductor process equipment. These applications can include crowbars, capacitor charging or discharging, and high voltage power supply protection circuits. Bulk ceramic resistors can provide low inductance, high average power per unit size, stability at high voltage, and durability at extreme peak-power levels.

Snubber circuits

When a spike in voltage occurs from electrical switching, an RC snubber circuit is typically used to suppress the discharges and protect the circuit. However, a wire wound or film resistor may not hold up to the high voltage, current or energy conditions.  The power spike can result in megawatts of instantaneous peak power which a small mass of film or wire-wound resistors would potentially degrade and even fail.

High-frequency filters

Bulk ceramic resistors are used extensively for high-frequency loads in broadcast and communication equipment because of their non-inductive characteristics. They provide excellent non-inductive power-handling capacity at frequencies into the GHz range, with no sacrifice in power dissipation. In advanced digital applications such as digital radio and HDTV transmitters involving pulses at high frequencies, the small size, flexibility and overload reliability of ceramic resistors are ideal.

Test loads

High energy may be desired in a testing situation, from addressing minor circuit spike to the diversion a lightning strike. In the case of power generators, test loads allow for a low-risk verification of a unit’s capabilities.

Useful Documents

Kanthal tubular resistors datasheet

Tubular Resistors Datasheet

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Axial-leaded Resistors Datasheet

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AS Series Slab Resistors Datasheet

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SP Series Slab Resistors Datasheet

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Series 900 Disk and Washer Resistors

 

 

 

 

 

Useful Links

Resistors

Ceramic resistors

Posted in Resistors | Comments Off on Bulk ceramic resistors vs film and wire-wound

EBG replacements for obsolete TT Electronics HV resistors

PPM Power can supply EBG alternatives for the high voltage resistors which TT electronics have decided to make obsolete.

  • Precision High Voltage Planar Resistors (PHP series)
  • High Voltage Thick film Resistors (HV31-HV35 )
  • High Voltage Low Inductance Thick film Resistors (HVL43-HVL45)

EBG replacements for TT Electronics obsolete HVL series

TT Electronic Part Power Rating (W) Voltage (kV) Resistance Min Resistance Max EBG Alternative Power Rating (W) Voltage (kV) Resistance Min Resistance Max
HVL 43 1.5 4 1k 1G OSX 26 1.95 4 100 10G
HVL 44 3.5 14 1k 2G SOX 52 3.4 16 400 10G
HVL 45 5 24 1k 4G SOX 78 5 24 600 10G

EBG replacements for TT Electronics obsolete HV series

TT Electronic Part Power Rating (W) Voltage (kV) Resistance Min Resistance Max EBG Alternative Power Rating (W) Voltage (kV) Resistance Min Resistance Max
HV31 0.5 1 1k 50M OGP 13 1 1.5 100 50M
HV32 0.75 2 1k 100M OGP 20 1.5 2 200 100M
HV33 1 4 1k 150M SOX 20 1.2 5 300 10G
HV34 1.25 7 1k 200M SOX 26 1.6 7.5 450 10G
HV35 1.5 10 1k 250M SOX 39 2.5 11 500 10G

EBG replacements for TT Electronics obsolete PHP series

TT Electronic Part Power Rating (W) Voltage (kV) Resistance Min Resistance Max EBG Alternative Power Rating (W) Voltage (kV) Resistance Min Resistance Max
PHVP5 1 5 1k 3G FBX8/5 1.6 6 200 2G
PHVP7 0.8 7 1k 1G FEX4/5 0.8 9 200 2G
PHVP7B 1 7 1k 2.5G MTX 967.3.25 1 8 10 30G
PHVP10 1 10 1k 1.5G MTX 967.3.38 1.5 10 10 30G
PHVP10B 1.3 10 1k 3.5G MTX 967.3.38 1.5 10 10 30G
PHVP10C 2 10 1k 7G MTX 967.10.25 2 10 10 30G
PHVP15 1.5 15 1k 4G MTX 967.15.38 3 15 10 30G
PHVP15B 2 15 1k 5G MTX 967.15.38 3 15 10 30G
PHVP15C 3 15 1k 10G MTX 967.15.38 3 15 10 30G
PHVP20 2 20 1k 7G MTX 967.5.51 2 20 10 30G
PHVP20B 3 20 1k 10G MTX 967.10.51 2 20 10 30G
PHVP20C 4.5 20 1k 20G MTX 967.15.51 4.5 30 10 30G
PHVP30 6.5 30 1k 30G MTX 967.25.99 10 35 10 30G
PHVP40 9 40 1k 40G MTX 967.25.99 10 35 10 30G

Useful Documents

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MTX967 series datasheet

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OGP series datasheet

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OSX/SSX/SOX series datasheet

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MTX967 series datasheet

 

 

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EBG extend two more resistor series up to 2000W

EBG have extended two more ranges of their ultra high power resistors up to 2000W. The UXP series already included the UXP2000.  Both the ULX and UTP series have now been extended to include 2kW variants. EBG’s ultra-high power resistors are used for demanding applications such as variable speed drives, power supplies, control devices, robotics and motor control.

ULX, UPT and UXP resistors series

Stability and improved heat transfer

EBG use their own METOXFILM technology for stability at high power and during pulse loading as well as alumina ceramic metalized with their special ALTOX film on the base for improved heat transfer and optimum discharge. The resistors are encapsulated in a resin-filled epoxy casing with large creeping distance, a large air distance between terminals and a high insulation resistance. The technology is designed to deliver low inductance and capacitance at high power.

One package – three resistors

EBG ultra high power resistors allow up to three resistors to be integrated into a single package, allowing power to be shared across more than one resistor as well as saving space and cost.

Features:

  • Tolerance range ±10 % to ±5 % (tighter on special request)
  • Resistance value ranges from 0.1 Ω to 1.5 MΩ (higher values on request)
  • Non-Inductive design
  • High insulation & partial discharge performance

Custom designs available

Many customers using EBG’s ultra high power resistors have custom designs to fit their application.  Parameters such as tolerance, resistance value and mechanical design can be modified to suit individual requirements. The resistors feature an easy mounting fixture to ensure an auto-calibrated pressure to the cooling plate of approximately 120 to 160 N. Materials comply with ROHS and UL94-V0 regulations.

For more information, please contact PPM Power on 01793 784389, sales@ppm.co.uk or use our website chatbox.

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Pre-applied phase change material for bonding semiconductor modules

The thermal transfer between a power semiconductor module (e.g. an IGBT or SiC module) and a heatsink is critical to achieving high power densities and avoiding failures in the field. Using phase change material rather than thermal grease as an interface achieves much higher conductivity. Furthermore, pre-application by the manufacturer ensures a uniform layer of optimal thickness and consistency which maximises performance, ease of manufacture and repeatability.

Rear side of a Vincotech module with pre-applied phase change material 

Dissipating thermal energy

The thermal energy generated by a power semiconductor die must be dissipated to avoid exceeding the maximum junction temperature (Tj max) and consequential damage. Poor mounting of a power module also risks failures in the field. Maximising the heat dissipation by minimising the thermal resistance between the module and the heatsink is typically achieved by bonding the two using a thermal interface material.

Thermal Interface Material (TIM)

The main role of a thermal interface material is to maximise the heat transfer by filling cavities on the power module and levelling out unevenness on the heatsink. This eliminates air gaps which act as thermal insulators to achieve an effective bond between the top of the heatsink and the bottom of the power module.

TIM conductivity versus grain and layer characteristics

Conductivity is highly dependent on the size, shape and distribution of the grains in the filling material. Smaller filler grains are able to fill small surface irregularities to reduce the contact resistance and lowers the thermal resistance (Rth). However, larger particles result in a high specific thermal conductivity. The optimum thickness of the TIM layer depends on the module size and technology. The layer should be as thin as possible but as thick as necessary.

What is thermal grease?

Thermal grease, often referred to as heat paste, heatsink compound or thermal compound basically consists of two components:

• a carrier material
• a filling material

Typical carrier materials include an epoxy, silicone, urethane or an acrylate. Fillers such as aluminium nitride, aluminium oxide, boron nitride or zinc oxide are thermally conductive but electrically insulating. A thermal grease compound can be as much as 80% filler.

Phase change material (PCM)

A phase change material changes state without a change in chemical composition. In the case of a semiconductor thermal interface material, the PCM changes from solid to liquid and back to solid when crossing the phase change temperature – approximately 45°C. Above the phase change temperature the material becomes thixotropic – i.e. viscous under normal conditions but less viscous when stressed. Thus, the PCM will spread across the area in contact with the heatsink, creating an even layer between the two surfaces but not flow when heated during power up of the module. Once solidified, there is no risk of smearing and a module requires no special care during transportation, handling and application.

Advantages of PCM

• PCM is fluid during the application and dries out over time and temperature.
• Compatible with press to fit pins
• Can be used with a standard solder profile such as J-STD-001, J-STD-003
• Reduced thermal resistance
• Reduced risk of substrate cracking

Comparison of thermal interface materials

Property Std thermal grease High perf. thermal paste Si-free thermal grease Phase change material
Density at 25 °C (g/cm3) 2.1 4.2 2.1 – 2.3 2
Dielectric strength (kV/mm) 10 3 20 N/A
Thermal conductivity (W/m*K) 0.81 2.5 2.5 3.4

Benefits of pre-application of PCM

Having phase change material pre-applied means streamlined production – i.e. a reduced number of manufacturing operations. This is also relevant to the design process during which a TIM layer would need to be manually applied. A screen-printing process applies a more uniform thickness and consistent quality of TIM than can be achieved manually with a squeegee, roller, brush or putty knife. Uniformity avoids increased thermal resistance due to the layer being too thin or too thick.

Conclusion

For high voltage semiconductor modules such as IGBT and SiC modules, phase change material offers significant performance benefits over traditional thermal grease as an interface material. Furthermore, pre-applied PCM ensures optimal thickness and consistency whilst reducing the number of operational steps in manufacture.

References

  1. Thermal Management Technology for IGBT Modules – Yoshitaka Nishimu, Mitsukane Oonota, Fumihiko Momose
  2. Maximizing Precision in Thermal Interface Layers – Martin Schulz, Infineon Technologies, Article Bodo’s Power Systems 01/2013
  3. The importance of correct IGBT module mounting procedures – Stuart Europower Components, July 20, 2016
  4. Reliability Testing Of Thermal Greases  – Arun Gowda
  5. Advantages of pre-applied Thermal Interface Material for power modules – Mirko Haardt, Field Application Engineer, Vincotech
  6. Vincotech’s modules with pre-applied phase-change material – Patrick Baginski, Field Application Engineer, Vincotech GmbH
  7. Application Note THERMAL PASTE APPLICATION AN10001 – Dieter Esau, 2010/03/30

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PPM Power Signs Agreement with SanRex to Supply Silicon Carbide Power Modules

PPM Power, specialist supplier of power electronics, high voltage and pulse power components has signed an agreement with Japanese manufacturer SanRex to distribute their power semiconductor modules in the UK. As well as the new silicon carbide (SiC) based MOSFETs, SanRex also manufacture schottky diodes and thyristor modules operating up to 2200 Volts and 500Amps. Typically these power modules are used in applications such as welding, induction heating, motor drives, battery chargers and grid connected inverters.

Best-in-class die technology and compact rugged packages

“Silicon Carbide MOSFETs have offered compact, high speed, very low loss power switching for a while now,” says Phil Surman – Sales Director at PPM Power. “SanRex have developed their own best-in-class die technology as well as compact, rugged transfer-moulded packages that deliver the next leap in performance at a system level. With silicon carbide MOSFETs and silicon based diode modules from SanRex, PPM Power now has semiconductor product offerings for mainstream power electronics as well as very high performance applications.”

About SanRex Corporation

Established in 1982 to support customers in The Americas and Europe, SanRex Corporation is a wholly owned subsidiary of Japanese company Sansha Electric. In addition to power semiconductors the company also manufactures plating rectifiers, lighting ballasts and plasma power supplies. SanRex is headquartered in Port Washington, New York.

About PPM Power

PPM Power has been serving the UK power electronics market since 1994. The company supplies a broad range of products from high voltage switches, resistors, capacitors and diodes to programmable power supplies, pulse transformers and simulation software. PPM Power is a division of Pulse Power and Measurement Ltd. which also manufactures RF over fibre systems used in applications such as satellite communication and electromagnetic compliance (EMC) testing of aircraft. The company is based in Swindon, UK.

PR Contact

Joe Petrie
Marketing Manager
Pulse Power & Measurement Ltd
T: +44 (0)1793 784389
F: +44 (0)1793 784391

E: sales@ppm.co.uk

W: www.ppmpower.co.uk

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Best-in-class HV DC power supply – free 14-day trial

Heinzinger have expanded the production of their “best in class” EVO series of high voltage DC power supplies and are delivering new types from stock. Desktop/rack mount units are available up to 10kV and 3000W. Voltage classes 1.5kV, 5kV and 10kV are already in production.

Compared to an equivalent 3kW regulated DC power supply, the EVO is approximately half the weight, half the size and delivers double the stability of line and load regulation – for a lower price.  A 14-day, no obligation trial period is available for customers to test the units.

Features & Options

Standard features:

  • Overvoltage and overcurrent protection
  • Limit functions for voltage and current
  • Interlock function
  • Easily configurable diverse I/O contacts
Optional functionality:

  • Ramp function
  • Arc detection
  • Fast discharge circuit
  • Electrical polarity reversal

Fully digitally regulated, best in class performance

Fully digitally regulated system based on a microcontroller and supported by an FPGA for measurement routines delivers outstanding speed and accuracy. The system is easily configured and is equipped with a huge variety of pre-configured settings. Standard units deliver an accuracy and stability class of 100 ppm. Optional high precision units provide an overall accuracy better than 10 ppm.

Customize to different loads

EVO high voltage power supplies can be customized to different load scenarios by configuring the regulation loop parameters.

Active power correction

The active power factor correctioninput stage meets multiple harmonic distortion standards, eliminating concerns with internal and external energy providers and minimizing interference in a lab environment. Units up to 3000 Watts are equipped with a single phase input@230V nominal ac voltage. The wide-range input allows voltages from 108 – 253 Vac.

Intuitive menu and extensive event memory

Backlit 3.5″ colour TFT screen ensures excellent readability of data and uses an intuitive menu for navigation. Well-designed sub-menus create a clear view in any operating condition. Access to sub-menus can also be protected using a numerical code. The units also have an extensive error and event memory file with time tags.

Communication interfaces

  • Designed for “plug and play” operation
  • Ethernet and RS232 using SCPI
  • Easy-to-use, basic web browser
  • Optional analogue interface

Practical chassis design

The enclosure can be used as a standardized 19″ chassis for industrial applications or a high-grade desktop device in a laboratory. No necessity for additional adaptors, which are never found when needed. The conversion from 19″ to desktop is achieved by modifying the position of two screws. Also, the air inlet grill can be equipped with an additional filter pad which can be changed easily from the front without tools.

Free software updates for 1 year

Software updates can be made using a special service plug on the rear side. Performance upgrades or updates for additional functionality are free for a year.

Useful links

Heinzinger EVO product page

All power supplies

High voltage programmable power supplies

Posted in Power Supplies | Comments Off on Best-in-class HV DC power supply – free 14-day trial

New 10kV optocoupler from Dean Technology

OPC10M – Optocoupler / Optical Switch

Dean Technology have announced a new 10kV high voltage optocoupler. The OPC10M is able to finely modulate a high voltage output signal up to 10kV by adjusting a reference low voltage input. The device is the first in a new series of optical devices that will be added to the HVCA product line over the coming months.

Smaller and lower cost

Dean’s optical switch products consist of a central diode and two or more LED drivers in a fully encapsulated and light-tight package. According to Dean, the device is exceptionally space efficient, and production methods allow lower costs than competitor solutions.  Custom parts for both are being produced now.

New optical switch line

“For a long time, we’ve built custom solutions for customers using this technology and we’ve put all of that learning into the OPC10M. It is a very useful and stable optical switch that we’re very excited to have brought to production”, said Lynn Roszel, Engineering Manager for Dean Technology.  “We are starting off our optical switch line with a 10 kV part that should provide a perfect solution for many of the applications where this kind of device can be used.” The company intends to release a wide range of new optical devices, starting with the OPC10M. A range of optical switches with higher voltages and power levels is planned. A full line of optical diodes with clear encapsulation is already in development.

More information?

For more information on the new line of Dean high voltage optical switches, please call 01793 7684389, email us on at sales@ppm.co.uk, complete an enquiry form or talk to us via the chat window.

 

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New Surface Mount Diode Package Up To 30kV

Dean Technology have introduced a longer high voltage surface-mount diode package covering 5,000 to 30,000 volts. The new package supports a much wider range of voltage and current performance than existing axial lead components. Custom diodes are also available for customers that have specific needs not met by the standard products.

The First Four Products: 5-15kV

The first four products released in this new size range from 5,000 to 15,000 volts with current handling up to 1,000 mA. The SLU08M and SLU15M use the same internal architecture as the axial lead UX-FOB and UX-F15B – parts that have been available from Dean Technology for many years and have continually out performed anything offered by competitors. The SLP05M and SLP10M are consistent with existing axial lead diodes supplied by Dean.

Increased Demand for Diode Package Variety

“We have been getting increased requests for variety in our surface mount diodes”, says Craig Dean, CEO of Dean Technology, Inc. “With this new package, we aim to meet those requests, and more. Throughout this year, we will release several new products in this size that will handle up to 30,000 volts. For engineers that want to take advantage of the time, quality, and cost advantages of surface mount technology, this is going to be an absolute win”.

SL Series Roadmap

Dean Technology has a long and extensive roadmap for new products in the SL series. A wide range of standard parts will be available covering from 5,000 to 30,000 volts and currents ratings that will cover most of the existing axial lead diode offerings. These products will be rolled out over the coming months, as well as an additional gull wing lead configuration.

Useful Links

High Voltage Diodes 

Posted in Dean, Diodes | Comments Off on New Surface Mount Diode Package Up To 30kV

New Genesys+ 5kW Programmable 1U Power Supply

TDK-Lambda recently launched the Genesys+™ series of programmable DC power supplies in a 1U 19” rack chassis. The 5kW model is the first in a series which uses Digital Signal Processing (DSP) technology to improve performance, functionality and offers efficiencies up to 93%. Genesys programmable power supplies are used in applications such as component, aerospace and automotive testing, semiconductor fabrication, water treatment, plating and solar array simulation.

  • Constant current, constant voltage or constant power modes
  • Internal resistance simulation
  • Accepts three-phase 170-265Vac, 342-460Vac or wide range 342-528Vac inputs with active Power Factor Correction
  • 1U high, 19” (483mm) wide rack
  • Five voltage models initially available: 0-10V/500A, 0-20V/250A, 0-30V/170A, 0-300V/17A and 0-600V/8.5A

Improvements over standard Genesys range

  • Two user-programmable output control pins can activate external devices, such as load disconnect relays
  • Arbitrary waveform profiles (e.g. car battery simulation at vehicle start) of up to 100 steps
  • Advanced parallel master/slave system allows a multi PSU system to achieve dynamic response, ripple and noise performance comparable to a single power supply.
  • Up to four units can be connected in parallel using a data link cable. The master and slave units automatically detect the parallel data connection and set their parameters accordingly
  • Faster up and down programming response times speed up operation with user adjustable voltage and current slew rate control

Compatible with existing models

The new series is compatible with Genesys™ and Z+ models, using the same communication protocols and signals. All functions can be programmed via the front panel or remotely using the LAN (LXI 1.5), USB 2.0 or RS232/485 communications interfaces. An isolated analogue control and monitoring interface (0-5 or 0-10V) is also provided. GPIB (IEEE488) is available as an option.

Interface options

The Anybus CompactCom platform enables various interface options as they are introduced e.g. Devicenet, Ethercat, Modbus and Profibus. A full package of software drivers, waveform creator and virtual front panel GUI is provided.

Safety features

  • Safe Start – the power supply will return to its last operational settings after a power interruption but with the output disabled.
  • Auto Re-Start – the power supply returns to the last used operation settings after a power interruption.
  • Last Setting Memory – retains settings such as the output voltage/current, output on/off, OVP/UVL level, Fold-Back and Start-Up mode at each AC input turn-off sequence.
  • Built-in protective functions – include over voltage protection (OVP), under voltage limit (UVL), fold-back protection (FOLD) and over-temperature (OTP) protection.

Certifications

Safety certifications include IEC/EN/UL 60950-1 with CE marking for the EMC, LV (low voltage) and RoHS Directives. The series conforms to the industrial environment IEC/EN61326-1 standard for conducted EMI, radiated EMI and EMC immunity.

Useful Links

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Comparison of Transducer Technologies for Current Measurement

Three key questions to ask when choosing a current transducer:

  • How accurate does the measurement need to be?
  • What current range needs to be covered?
  • What is the operating temperature range?

Higher accuracy, a wider current range and greater stability over temperature are three major factors that will increase the cost of a transducer.

Current transducers in order of decreasing performance and cost:

Accuracy and Sources of Error

The total error of a current transducer is given by the sum of the ratio error, the thermal drift, the DC offset and the linearity. All four sources of error are related to the technology. Ratio Error (aka Gain Error) can be considered to be fixed since this is an error resulting from the number of turns in the transducer. The other three sources of error can vary during measurement.

The error equation

Total Error = Ratio Error + Thermal Drift + DC Offset + Linearity

Approximate Sources Of Error By Technology

Technology Ratio Error (aka gain error) Thermal Drift DC Offset Linearity
High Precision ppm ppm ppm ppm
Fluxgate 0.2% ppm ppm ppm
Closed Loop 0.4% 0.05% 0.1% 0.05%
Open Loop 1% 0.1% 0.2% 0.2%

Temperature

Most current transducers offer reasonable accuracy at room temperature. However, the performance of different technologies vary over a temperature range. High Precision and Fluxgate current transducers deliver temperature stability which can be quoted in terms of ppm/degC.  Whereas an open loop transducer will typically vary by 0.1%/degC, which over a range up to 85degC amounts to a sizeable error. If measurements are to be performed at room temperature then an open or closed loop transducer will probably be adequate. However, accurate measurements over a wide temperature range mean that a more costly Fluxgate or High Precision transducer is more appropriate.

Accuracy

Generally, high levels of accuracy rely on more expensive materials and manufacturing processes. It is therefore advisable to consider a transducer that delivers adequate performance over one that delivers a higher degree of accuracy if cost is an issue.

Current Range

All four technologies discussed here support current transducers up to 2kA, with high precision solutions available up to 26kA. For Open-Loop, Closed-Loop and Fluxgate transducers the cost penalty for increasing current range between 1kA and 2kA is much less than the cost per amp relationship below 1kA.

At very low currents, High Precision transducers are orders of magnitude more expensive than Fluxgate, Open-Loop or Closed-Loop because of the nature of the design. High Precision is therefore an expensive solution below 1kA, above which the difference is less marked.

Fluxgate Transducers

Unlike Open-Loop and Closed-Loop transducers, Fluxgate transducers are not based on the Hall effect. Accurate measurement of DC current is based on compensating the current linkage created by the current to be measured by creating an opposing current linkage flowing through a known number of turns. To obtain an accurate measurement, it is necessary to have a highly accurate device to measure the condition precisely.

Fluxgate detectors rely on the property of magnetic materials to exhibit a non-linear relationship between the magnetic field strength and the flux density. The detection of the zero flux condition is based on observing the variation of the magnetic field strength and the flux density. This phenomenon allows a Fluxgate transducer to be very sensitive to small values of a residual magnetic flux created by the current linkage and therefore maximise the level of the detector output signal.

Closed-Loop Hall Effect

Similar to Fluxgate transducers, the magnetic flux created by the primary current in a Closed Loop hall effect transducer is balanced by a complementary flux produced by driving a current through the secondary windings. A hall device (rather than a fluxgate) and associated electronic circuit are used to generate the secondary (compensating) current. The secondary current is therefore an image of the primary current. Closed loop transducers offer a wide frequency range, low temperature drift, good overall accuracy, a fast response time and excellent linearity.

Open-Loop Hall Effect

An Open-Loop Hall Effect transducer works because the magnetic flux created by the primary current is concentrated by a magnetic circuit into an air gap which is then measured using a Hall device. The output signal from the Hall device is then conditioned to provide an exact representation of the primary current at the output. Open-Loop Hall Effect transducers are small, light, offer low power consumption and a wide measuring range.

Useful Links:

Hall effect current transducers
Zero flux precision current transducers
Rack mounted current transducers

Posted in Current Transducers | Comments Off on Comparison of Transducer Technologies for Current Measurement

More Information?

Telephone +44 (0)1793 784389 or email: sales@ppm.co.uk