8x8mm aperture extends transducer options

7th April 2014

LEM

Mick Elliott

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Datasheet

LEM has added three new members to its HO series of PCB-through-hole mounting current transducers, which provide an aperture of 8 x 8 mm to carry the primary conductor under measurement, extending the options for this form-factor. The new models, for 6, 10 or 25 A nominal measurements of DC, AC, and pulsed signals benefit from the revised LEM Open-loop Hall-effect ASIC (Application Specific Integrated Circuit) introduced several months ago with the launch of the HO 8, 15 and 25-NP & –NSM models.

Using the latest LEM-developed ASIC, combined with Open-loop Hall-effect technology, the new devices meet the demand for high performance and quality at a lower cost.

The HO 6, 10 and 25-P models’ offset and gain drift are twice as accurate (over the temperature range -25 to +85ºC) as the previous generation. A high level of insulation between primary and measurement circuits, due to the high clearance and creepage distances of more than 8mm and a CTI (comparative tracking index) of 600, allows a test isolation voltage of 4.3 kV_RMS/50Hz/1min.

In addition, the HO xx-P series delivers better performance in other areas such as response time, power supply and noise, allowing the development of more technically advanced power electronics applications.

The transducers require a PCB mounting area of only 2.88cm² and weigh only 10g. They can measure up to 2.5 times the primary nominal current but also incorporate an additional pin providing an over-current detection set at 2.63 x the nominal current I_PN(peak value). The products also provide fault reporting in the case of memory contents being corrupted. LEM's HO xx-P transducers operate from a single supply voltage at 3.3 or 5V.

The new range delivers its output as a scaled analogue voltage; in most systems this will be converted to a digital value by an analogue/digital converter (ADC) which requires a reference voltage. The HO xx-P series can also be configured to make measurements relative to an external reference.

LEM’s HO xx-P models are ideal for a range of applications where mounting flexibility offered by the aperture and a small size is needed, such as in solar combiner boxes and solar-power inverters, as well as small smart meters, variable speed drives, uninterruptible and switch-mode power supplies, air conditioning, home appliances, static converters for DC motor drives, and robotics.

The transducers are CE marked, conform to the EN 50178 standard and are recognised for industrial applications with a wide operating temperature range of -40 to +105°C. LEM offers a five-year warranty for each transducer.