American Magnetics 4Q06250PS-430 Integrated Power Supply System - Manual (Page 35)

Rev. 5 17
Installation
Magnets w/o Persistent Switch
k. Remote communications via Ethernet and/or RS-232 can be
accomplished by connecting suitable cabling to the Model 430
Programmer rear panel ETHERNET and/or RS-232 connectors.
2.6 Special Configurations
The Model 430 Programmer has been designed for optimal operation with
a superconducting magnet (i.e. a very low resistance, high inductance
load) with a persistent switch. The Model 430 Programmer is capable of
controlling current to other loads; however, some modification to the
Model 430 Programmer settings and/or connections must usually be made.
Two commonly encountered configurations are: 1) superconducting
magnets without a persistent switch, and 2) operation on a short-circuit or
low resistance load.
2.7 Superconducting Magnets with No Persistent Switch
An external stabilizing resistor for superconducting magnets without a
persistent switch is no longer required
1
. However, these systems do
require a specific Model 430 Programmer stability setting based on the
magnet inductance as follows:
For magnet inductance <= 100 Henries (H):
Stability Setting = (100 - H)
For magnet inductance > 100 Henries:
Stability Setting = 0
2.8 Short-Circuit or Resistive Load
If operating with a short-circuit as a load without the presence of a
superconducting magnet, the Model 430 Programmer must be manually
configured for stability. Normally, when the persistent switch heater is
deactivated, the Model 430 Programmer sees essentially a short-circuit
load since the persistent switch shunts all current flow away from any
connected magnet. Therefore, one method of operating a short-circuit is to
indicate that a persistent switch is present, with the persistent switch
heater deactivated.
The preferred method is to indicate that a persistent switch is not present
(see section 3.10.2.6 on page 54) and adjust the stability setting (see
section 3.10.2.1 on page 48) to control the load. A stability setting of 100%
1. Effective with Model 430 firmware version 1.62.