American Magnetics 05100PS-430-601 Integrated Power Supply System - Manual (Page 158)

140 Rev. 5
Service
Troubleshooting Hints
5.2.3 FAILURE TO LOAD message displayed after power-up
1. Power the Model 430 Programmer off using the front panel power
switch.
2. Wait at least 15 seconds.
3. Power the Model 430 Programmer on using the front panel switch.
5.2.4 Power supply unstable - magnet voltage oscillates
Note
If the size of the voltage oscillation is small (approximately 0.1 volt
or smaller), see step 1, below. If the voltage oscillation is larger than
approximately 0.1 volt, see steps 1 through 4, below.
1. Adjust the persistent switch heater current to a value 10 mA larger
than the present value. If the oscillation stops, adjust the heater
current to as small a value as possible that maintains magnet
voltage stability.
2. Verify the power supply controlled by the Model 430 Programmer is
configured for remote programming, voltage-to-voltage mode.
Consult the manufacturer’s operations manual for the necessary
power supply configuration.
3. Verify that the persistent switch heater is operating. Also, verify
that the actual persistent switch in the magnet is correctly
installed and connected.
Note
If the persistent switch heater is activated without an inductive load
present at the supply outputs, oscillating current will result. The
Model 430 Programmer is designed to operate large inductive loads
with only relatively small resistive characteristics (i.e.
superconducting magnets). The Model 430 Programmer is not
designed for use as a general purpose power supply controller for
resistive loads.
4. If the magnet has no persistent switch installed, or has a small
inductance (typically less than 3 H), then adjust the stability
setting for the Model 430 Programmer. As this setting is increased,
the system should become more stable. For best results, minimize
the amount that this value is adjusted from 0.0%. Refer to section
3.10.2.1.