C. Gyrator Circuitry
A gyrator inverts the current-voltage and impedance characteristics of linear electrical elements. Thus, a gyrator can make a capacitive circuit behave inductively. Positive attributes of the gyrator include that it has no moving parts and can be implemented in a fairly compact printed circuit board. Ultimately we discarded the idea of implementing the gyrator circuit in this ATS because we preferred the PSEUs see a true inductance on their sensor inputs rather than a simulated inductance.
D. Saturable Core Reactor
The saturable core reactor is an attractive choice in the PSEU application for a number of reasons. It has no moving parts, presents a true inductance to the PSEU sensor inputs, is very compact and is quite inexpensive (costing less than $100 even in small quantities). The question of compactness and expense, though, requires further consideration. This is because implementation of the saturable reactor also requires a current source for the control winding and an inductance meter to calibrate and control the resulting inductance. As the requirements for precision and resolution of the variable inductor increase, so too do the corresponding requirements for the current source and inductance meter. If these instruments are already present in the ATS, the impact is minimal. If they must be incorporated solely to support the saturable reactor, their cost and space requirements become important considerations.