American Magnetics 4Q12125PS-430 High Stability Integrated Power Supply System - Manual (Page 27)

Rev. 5 9
Introduction
Operating Characteristics
1.6 Operating Characteristics
The Model 430 Programmer has
been designed to perform with var-
ious power supplies to allow the
user the greatest degree of system
flexibility. The power supply and
Programmer combination are cate-
gorized by one of three forms: sin-
gle-quadrant, dual-quadrant, and
four-quadrant. For sake of clarity,
the term quadrant is defined as
one of four areas of a cartesian
coordinate system where the
abscissa is current and the ordi-
nate is voltage. Refer to Figure 1-3.
1.6.1 Four-Quadrant Operation
The four-quadrant magnet power supply system illustrated in Figure 1-4
offers the most control of all the modes of operation. Efficiency is increased
and reversible magnetic field profiles are attainable without
discontinuities in the current. All of the voltage and current control is
performed electronically so that system reliability is improved.
Disadvantages of the four-quadrant system include somewhat increased
cost of the power supply over single or dual-quadrant power supplies, and
added complexity in protecting the power supply in the event of AC power
loss or magnet quenching. Nonetheless, modern four-quadrant power
supplies which include integral output protection against AC power loss
and magnet quenching are available at reasonable prices.
20
-20
200 -200
V
I
Positive Current
Flow Direction
Positive Voltage
Polarity
Positive Current
Flow Direction
Negative Voltage
Polarity
Negative Current
Flow Direction
Positive Voltage
Polarity
Negative Current
Flow Direction
Negative Voltage
Polarity
1 2
4 3
Figure 1-3. The Four Regions, or
Quadrants, of System Operation.
Magnet
Coil(s)
Persistent
Switch
(optional)
Misc. Line Losses
Model 420
Shunt
V
Four-Quadrant
Power Supply
Current
Figure 1-4. Four-Quadrant System with Resistive Shunt
430