American Magnetics 420 Power Supply Programmer - Manual (Page 29)

Rev. 7 11
Introduction
Operating Characteristics
reversing the contacts and resuming magnet energization. This pause
precludes smooth magnetic field reversals.
1.5.4 True Four-Quadrant Operation
The true four-quadrant magnet power supply system illustrated in Figure
1-5 offers the most control of all the modes of operation. Efficiency is
increased and reversible magnetic field profiles are attainable without
discontinuities. All of the current switching is performed electronically so
that system reliability is improved. Disadvantages of the four-quadrant
system include the increased cost of the power supply if smooth,
continuous field polarity reversal is not a requirement, and added
complexity in protecting the power supply in the event of AC power loss or
quenches.
Magnet
Coil(s)
Persistent
Switch
(optional)
Misc. Line Losses
Model 420
Shunt
V
Four-Quadrant
Power Supply
Current
Figure 1-5. True Four-Quadrant System