The CTSR family of transducers has been specifically designed to meet the latest safety standards that have been issued in respect of solar installations and inverters, namely VDE 0126-1-1, UL 1741, and IEC 60950-1. The devices are PCB mountable, lightweight (28g) components, with a 20.1 mm diameter aperture that easily accommodates multiple conductors. The residualcurrent capability measures the sum of all of the instantaneous currents flowing through the aperture, in single- or three-phase configurations. Conductors may be carrying primary currents of up to 30A/wire (AC or DC).
The CTSR 0.3-P and CTSR 0.6-P safely measure nominal currents of 300 and 600 mA
respectively, to a maximum accuracy of 1.9% and 1.5% respectively at +25°C ambient temperature, without offset, providing an analogue output to trigger a safety system in the event of a high leakage current. They both provide a high overload capability up to 3300A (for a pulse duration of 100μs, and with risetime of 500 A/μs), as well as a very high level of insulation between primary and measurement circuits, thanks to long creepage and clearance distances (11 mm), coupled with a CTI (comparative tracking index) of 600V.
These products can also be supplied with a primary inserted conductor (made up of 4 individual conductors), and in that configuration have the designation “CTSR xxx-TP”. CTSR-series transducers operate from a +5VDC supply and have a typical current consumption of just 17.8 and 18.1 mA unipolar when measuring 300 and 600 mA respectively as nominal primary residual current (CTSR 0.3-P and CTSR 0.6-P models); They provide access to their internal reference voltage, and to options such as self test and demagnetisation.
Models with higher nominal current range up to 3 ARMS to meet the needs of specific customers can be developed on request. As well as ensuring safety in solar inverter installations, LEM’s CTSR range is also ideal for a range of applications that includes symmetry fault detection in medium power inverters, failure detection in a range of power sources.
The transducers are CE marked, conform to the EN 50178 standard and are recognised for industrial applications with an operating temperature range of -40 to +105°C. LEM offers a fiveyear warranty for each transducer.