LEM sets new benchmark for accuracy in Rogowski coil sensors

LEM announces the introduction of the first AC current sensors family of components based on patent-pending Perfect Loop Technology. After calibration, the new RT series achieves absolute accuracy of better than 0.65% - including the position error - making them the first split-core Rogowski coils to be suitable for use in Class 1 power devices.

An imperfect coil structure induces an unbalanced geometry and increases sensitivity to the position of the measured conductor within the sensor, or to the proximity of external electric cables. The RT series of sensors overcomes the problem of asymmetry resulting from the discontinuity at the sensor opening, which is inherent in conventional split-core Rogowski coils. Whilst other manufacturers use complex and costly clasp designs to minimise the effects of discontinuity, LEM engineers have invented a unique, patent-pending magnetic coupling technology that allows a perfect extension of the magnetic flux at the loop opening which compensates for coil asymmetry.

In addition, LEM has developed an advanced coil-winding process which produces exceptionally regular windings, to further enhance sensor symmetry, accuracy and immunity to electromagnetic interference.

Sensors based on conventional Rogowski coil technology combine almost perfect linearity, with no saturation or upper limit in the current rating, a large frequency range which includes 50/60 Hz, and an ultra-compact and flexible form. LEM’s RT sensors retain these key benefits whilst overcoming susceptibility to asymmetry caused by discontinuity at the sensor opening, and minimizing unevenness in the coil winding.

The Rogowski coil principle provides very precise detection of the rate of change (derivative) of the primary current that induces a proportionate voltage at the terminals of the coil. A simple electronic integrator circuit, typically within the device to which the sensor is connected, is used to convert the voltage signal into an output signal that is proportional to the primary current. This eliminates the need for an additional power supply, as the RT sensor is self-powered.

The very thin, light and flexible format of RT sensors allows them to be fitted into applications in which traditional current transformers are typically too heavy and bulky, especially when measuring high currents. Their split-core construction allows them to be easily wrapped around the conductor without dismantling cables or shutting down operation. The benchmark accuracy of RT series sensors provides enhanced performance in current and power monitors as well as energy meters.

The 5 mm gauge RT sensors are currently available with sensing apertures with diameters of 55mm or 125mm and have a five-year guarantee.

Comments

Post a Comment

Popular posts from this blog

Han® HC 250 high current contact

A Powerful Solution HARTING has developed the new Han® HC 250high current connector as a powerful interface that impresses by requiring little space, transmitting high current intensities and allowing flexible configuration of the number of poles. The HC 250 one-pole crimp module can be connected in various frame geometries to produce the required number of poles in a compact space – and in the existing Han® HPR housing. Technical details: - Rated current 250 A at a rated voltage of 2000 V - Termination cross-sections are: 35 mm2, 50 mm2 and 70 mm2 - Maximum four-pole interfaces in a size 24 B HPR housing, making it particularly suitable for motor connections - High quality plastic with good smoke and inflammability levels - Removal tool for simple installation and removal of the contacts and inserts - Confusion of a number of interfaces is reliably prevented by multiple coding options for the individual inserts The requirements in the railway industry are changing, as
Read more

EGCS-D0 Accelerometer Now Available in 10,000g Range

Measurement Specialties, Inc. (NASDAQ: MEAS) has recently redesigned the EGCS-D0 accelerometer to enable it to accurately and reliably measure up to ±10,000g. This rugged device is critically damped, which is the ideal mechanism to protect the accelerometer against ±20,000g impacts and prevent sensor ringing. The EGCS-D0 accelerometer is now available in ranges from ±5g to ±10,000g which makes it ideal for both critical low-g measurements and high-g impacts. These units feature a Wheatstone Bridge mV output with a standard compensated temperature range of 20ºC to 80ºC (other options available). The EGCS-D0 was specifically designed for impact and shock testing in auto safety, aerospace, military and civil engineering applications. Designed to be bolt-mounted, this device operates from 2-15Vdc excitation with electrical output ratiometric to voltage input. Optional triaxial mounting blocks (MTG-F4), signal conditioners (Model 101) and auto-zero inline amplifiers (Model 140) are avai
Read more
Ilix Cermet Reamers Are Ideal For Dry Machining Engineers Cutting Tools, the UK agent for Ilix, has introduced Ilix solid-carbide and cermet reamers for the machining of hard metals. The machine reamers 6372C and 6323 allow the production of high-precision holes with good surface finish. Compared with HSS, the solid-carbide qualities enable the increase of cutting parameters and tool life. The quality of the reamers is said to guarantee high performance, even for hard metals with a resistance more than 1200N/mm2. The Ilix carbide 6372C range of hundredth reamers is from 0.98mm through to 12.05mm in increments of 0.01mm. The reamers are manufactured to a tolerance of +0.000 - +0.004mm. The cermet reamers 6323 have new cutting geometry developed by Ilix. These reamers are said to be ideal for steel machining, having high chemical stability during the cutting process. They offer good wear resistance due to the high hardness and have low material adhesion. The Ilix cermet reamer is said to
Read more