American Magnetics 05200PS-430-601 High Stability Integrated Power Supply System - Manual (Page 192)

174 Rev. 5
Appendix
Model 601 and Energy Absorption
Figure A-4). A properly selected power supply will provide the required
charging voltage and current.
Once the magnet is charged, there is no changing current and V
magnet
becomes zero in steady state, with the power supply providing only the
voltage required for the resistive IR drops.
A.13.3.2 Magnet Discharging
To begin discharging or reducing the charge on a magnet, the power
supply voltage will decrease. As the voltage drops, the magnet polarity
reverses in its natural attempt to oppose any change in current. Current
Figure A-4. Loop Voltages - Magnet Charging
Figure A-5. Loop Voltages - Magnet Charged (Steady State)