Residual current monitor

A power distribution unit (PDU) comprising:

• a housing;
• at least one power input associated with said housing, said at least one power input including a plurality of power conductors;
• a plurality of power outputs electrically connected to said at least one power input for providing power to electrical equipment;
• and
• a residual current monitor (RCM) associated with said at least one power input for detecting a presence of downstream leakage current, said RCM comprising:
• a sensor, including:
• a core susceptible to magnetization, at least some of said plurality of power conductors intersecting said core;
• a plurality of drive windings about said core;
• drive circuitry operative to produce alternating drive signals through said plurality of drive windings sufficient to drive said core into and out of positive and negative saturation;
• sensing circuitry responsive to said downstream leakage current on said plurality of power conductors corresponding to leakage current to bias at least one of said alternating drive signals and produce a response signal;
• and
• a high-order current signal filter for removing high frequency components of said response signal to isolate characteristics of said downstream leakage current.

A power distribution unit (PDU) comprising:

• a housing;
• a power input including a plurality of power conductors for providing power to components within said PDU;
• a plurality of outputs for providing power to electrical equipment;
• and
• a residual current monitor (RCM) for detecting a presence of leakage current, said RCM comprising:
• a sensor responsive to leakage current to produce a response signal representative of said leakage current, wherein said sensor includes an annular ferromagnetic core surrounding at least some of said plurality of power conductors and at least a pair of drive windings which generate flux about said annular ferromagnetic core in opposite directions, whereby presence of said leakage current, corresponding to a net current on power conductors passing through said annular ferromagnetic core, induces said response signal on said drive windings, wherein said presence of said leakage current affects a duty cycle of said response signal;
• and
• a filter operative to isolate characteristics of said leakage current from said response signal.