User Manual    AMETEK Programmable Power 
RS Series    138 
5.7.4  Filter Boards 
A set of two identical inductor boards is located behind the Modulator board and next to the four 
amplifier boards. One filter board handles the "A" output, the other handles the "B" output. In 
addition to the filtering function performed by these boards, the inductor boards also contain 
current sensors that are used in the feedback loop of the amplifier. The output of these current 
sensors is routed to the modulator board to regulate current sharing and peak current limiting. 
5.7.5  Fan Supply Board 
The Fan Supply board is located in the wind tunnel of the PFC section at the bottom of the 
power module.  This board provides variable speed control for the dual fans of the power 
module.  Fan speed is a function of the load current sensed.  This provides for lower levels of 
audible noise during minimal load conditions. 
5.7.6  Output Snubber Board 
A small output snubber board is attached to the output terminals of each power module. This 
snubber provides the required operating stability of the amplifiers.