A calibrated resistor of known low value placed in the rectifier output, anode leads or bonds. Reading the millivolt drop across it and applying its factor gives the current without breaking the circuit. Rectifier shunts are rated by current and millivolts, such as 25 A at 50 mV, a factor of 0.5 A per mV, and using the wrong factor is one of the commonest sources of bad current data.
Shunt reads 31 millivolts and it's a 50 amp 50 millivolt shunt, so the rec is putting out 31 amps.
Read the rating stamped on the shunt itself, not the rectifier nameplate. Replacement shunts often have a different factor.
Also heard as
- current shunt
- meter shunt
Related terms
Rectifier
Transformer-rectifier unit that turns AC power into adjustable DC current for an impressed current CP system.
Tap
Adjustable transformer setting on a rectifier, used to raise or lower DC output in coarse and fine steps.
Bond
Wire or cable connection that ties two metal structures together electrically, often to control CP current.