Riedon, Inc. is introducing a range of UL-listed, RoHS-compliant, precision current shunts designed for dc ammeters and similar instruments. The RS Series of off-the-shelf, base-mounted shunts offers current ratings from 5A to 1200A and combine low cost with the industry’s shortest lead-times while Riedon’s custom design capability caters for more unique requirements. These devices are targeted at applications in the renewables energy market, such as solar arrays, wind turbines, and battery chargers for energy storage e.g. in electric vehicles, as well as other uses in heavy industry, electroplating and mining.
The principle of current measurement using a shunt resistor depends on measuring the small voltage dropped across a precision resistor placed in series with the load. Riedon offers standard parts that provide 50mV and 100mV outputs but can also provide custom output voltages. The very low resistance values required for shunt resistors, 10mÎ© at 5A and just 0.05mÎ© at 1000A, are provided by Manganin® resistive elements. These are precision etched to a standard tolerance of ±0.25%, with ±0.1% devices also available.
"Our in-house manufacturing and design capability it what sets Riedon apart from many other suppliers. We can compete on price and delivery while also supporting custom designs," said Phil Ebbert, Riedon's VP of Engineering, "And, as far as I know, Riedon is the only manufacturer to offer precision DC ammeter shunts that are UL approved and fully RoHS compliance"
Riedon's RS range is divided into three different-sized body styles determined by current rating. All feature a 4-terminal design, which separates the heavy-duty load carrying connections from the voltage sensing terminals. Terminals are brass for the RSA (5 – 150A) and RSB (170 – 600A) parts but copper for the RSC (800, 1000 and 1500A) units. Operation is specified over a temperature range of -40 to +80 degrees C with a temperature coefficient of resistance (TCR) of ±15 ppm/degree C and a dielectric strength (terminal block to base) of 750Vdc.