ETS-Lindgren's 91550-5 Current Probes are optimized for making high power, low duty cycle pulse current measurements. While the original purpose was to enable measurement of radar transmitter transmission lines, 91550 series probes are also very valuable in making current inrush measurements on large loads such as electric motors. Under the new version of MIL-STD-461D/MIL-STD-462D, inrush current associated with automatic mode switching of the EUT is controlled under CE102 (similar to present CE03, but a LISN based voltage requirement). It is important for the test engineer to ensure that the current probe (used as a diagnostic tool in this application) is operating in its linear region during the entire operation of the test. Both frequency and time domain measurements are easily effected with this probe family, with low risk of probe saturation during the inrush event. The difference between individual probes in this family relate to sensitivity and pulse current capability. The higher the sensitivity, the lower the pulse current capability.
91550 series probes have a 3.18 cm (1.25 in) window, making them suitable for measurements on most power cables (AWG 4/0 cable, good for several hundred amps, is 12.7 mm (0.5 in) diameter, exclusive of insulation). Probe saturation current is compatible with the current carrying capacity of wires placed in its window. In those cases where the window is not large enough, our 93686 series probe family has similar capabilities with a 6.65 cm (2.62 in) window.