These relays have an input for three phase current. In the field, these inputs are taken from current transformers that step down current from the main bus to anywhere from 0 - 7+ amps. So the relay itself actually sees from 0-7+ amps. It is set to trip at some point in that range.
These inputs are non resistive, and only slightly inductive. There are internal coils inside the relay. I'm fairly certain their impedance is negligible. This is an AC application
So what I am looking for is a current source only. No voltage, no power. Strictly current. What I am trying to build is similar to a Doble or any other brand of relay test set without all the extra features.