Service – American Magnetics 4Q1010PS-430 Integrated Power Supply System User Manual
Page 156
138
Rev. 5
Service
Troubleshooting Hints
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
5.2.5 The power supply system will not charge the magnet.
1. Verify system interconnecting wiring. Refer to section 2.5. If the
Model 430 Programmer shows “+0.00 A ↑ Status: Ramping” with
the supply voltage, Vs, increasing or at the programmed Voltage
Limit (as indicated by the reverse video “V” status indicator), there
may be a problem with the power supply. Verify the power supply is
on and the program out connection from the Model 430
Programmer to the program voltage input to the power supply is
intact.