Deltec Company Resource Section

An ammeter shunt is a very low-resistance connection between two points in an electric circuit that forms an alternative path for a portion of the current. Shunt voltage drop is used in conjunction with an ammeter to measure amperage of a circuit. Commercially manufactured shunts are typically available in either 50 or 100 millivolts.


Shunt Definition

Deltec ShuntsAn ammeter shunt is a very low-resistance connection between two points in an electric circuit that forms an alternative path for a portion of the current. Shunt voltage drop is used in conjunction with an ammeter to measure amperage of a circuit. Commercially manufactured shunts are typically available in either 50 or 100 millivolts.

Shunt Operation

For continuous operation, it is recommended that shunts are not used at more than 2/3 of the rated current under normal operation conditions. Shunts should be located in an area where freely circulating air is available. If this is not possible adequate forced ventilation should be provided to keep the shunt operating temperature at 40° - 60°C. Shunt temperature must be maintained under 145° C or a permanent change in resistance will occur.

Amp to Volt Relationship

Deltec DC ammeter shunts are listed by Series Type, Amperage and Voltage Drop. For example, an MKA-100-100 is a lightweight shunt, which will drop 100 millivolts at 100 amps with Deltec standard accuracy of plus or minus 1/4%. 66 continuous operation amps is acceptable for this shunt.
100 millivolts = (1/1000)*(100) Volt = .1Volt
50 millivolts = (1/1000)*(50) Volt = .05 Volt

Estimating Resistance

To estimate resistance of a Deltec Ammeter shunt one needs to apply ohms law. For example an MKA-100-50 has an approximate resistance of 0.0005 Ohms. This is determined by V/I=R. (.05 V)/(100 A) = (R).

OHMS LAW
V= I x R
V = Voltage I = Amperage R = Resistance Power (Watts) = I^2 x R
Ohms Law Calculator