Bruker EPR 12T Cryogen Free, User Manual, Page: 34 / 80

34 ZTKS0213 / Z31939 / Rev.: 01
Operation
To activate the heater the following conditions have to be met:
1. The magnet system must be deenergized. If the magnet is energized, the heater
cannot be activated, and the indicator remains inactive ("OFF").
2. The magnet must be below ambient temperature (300 K). While the magnet is at
ambient temperature the heater and the indicator remain inactive. This is a
protection against overheating the magnet. It will also make sure that the heater is
switched off as soon as the magnet reaches ambient temperature (after 1 – 2 days).
Magnetic Field Indicator
The magnetic field indicator shows whenever the magnet is energized and hazardous
fringe fields occur around the magnet.
The indicator can be placed on top or on the front panel of the BCFC. Make sure that the
indicator is clearly visible from all locations within the 5 G contour (see Appendix
Table A.8 and Figure A.3 on page 68 ).
There is a connector for an additional indicator on the rear panel of the BCFC in case an
external indicator needs to be installed for enhanced visibility.
Emergency Quench and Status Indicators
In case of emergency (e.g. fire), it may be necessary to quench the magnet intentionally
and to eliminate the hazardous magnetic fringe field. The quench can be executed via
an emergency button ("Magnet Quench") on the front panel of the BCFC.
For remote control of the "Magnet Quench" option the BCFC is equipped with a
connector at the rear panel (see
Figure 5.9 ).
Activating the "Magnet Quench" will lead to the following actions on the magnet system:
• The compressor will be stopped immediately.
• A heater is activated in the magnet system which rapidly increases the magnet
temperature. Raising the magnet’s temperature will lead to a quench of the magnet.
The heater is backed by an internal UPS in the BCFC, so the "Magnet Quench"
functionality is available even during power failure (see also section
"Emergency
Quench" on page 43 ).