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--- turning_magnets_on_off [2015/10/19 14:46]
pereira [Set S800 magnets settings]
+++ turning_magnets_on_off [2017/05/26 15:37]
pereira [Arming of Dump Switch]
@@ Line 13: / Line 13: @@
 === Purpose ===
-The power supply for each of the spectrograph dipoles has a dump switch that must be armed to send current through the dipoles. The dump switch is in place to protect the conductors inside the cryostat from melting in the event that the magnet becomes non-superconducting while energized with high current. When triggered, the dump switch provides a high-current short circuit path to dump the energy from the magnet. The kinds of error conditions that will trigger the dump switches are the same conditions that trip off power supplies to other superconducting magnets on the beamlines.  Examples include: a lead drop fault error, a quench detection (read and set values not agreeing over a period of time), a cryogenic error condition (e.g., a low helium level or blown rupture disk), and a loss in flow of cooling water for the power supplies.
+The power supply for each of the spectrograph dipoles has a dump switch that must be armed (closed) to send current through the dipoles. The dump switch is in place to protect the conductors inside the cryostat from melting in the event that the magnet becomes non-superconducting while energized with high current. When triggered, the dump switch provides a high-current short circuit path to dump the energy from the magnet. The kinds of error conditions that will trigger the dump switches are the same conditions that trip off power supplies to other superconducting magnets on the beamlines.  Examples include: a lead drop fault error, a quench detection (read and set values not agreeing over a period of time), a cryogenic error condition (e.g., a low helium level or blown rupture disk), and a loss in flow of cooling water for the power supplies.
-While designed to protect the magnet from a more expensive repair if the magnet quenches when energized, it is possible that the dump switch can get damaged if triggered because of the large amount of energy involved.  Therefore, the magnet should be ramped down before any planned trigger conditions occur.
+While designed to protect the magnet from a more expensive repair, if the magnet quenches when energized, it is possible that the dump switch can get damaged if triggered because of the large amount of energy involved.  Therefore, the magnet should be ramped down before any planned trigger conditions occur.
 === Operation ===
-The dump switches of the first and second dipoles are located on the bottom and middle level of S3. The two pictures below show the dump-switch control for the second spectrograph dipole. A label in the control box explains how to arm the switches.
+The dump switches of the first and second dipoles are located on the bottom and middle level of S3. The dipole magnet is ready to be turned on when the front panel of the dump switch box shows the red label "closed". The two pictures below show the dump-switch control "open" (not ready to be turned on) for the second spectrograph dipole. A label in the control box explains how to arm the switches.
@@ Line 28: / Line 27: @@
 ===== Turn on S800 magnets power supply =====
+  * **Troubleshooting**: if a power supply cannot be turned on from PanelMate, check that the power supply module is ON. The modules for all S800 magnets are located in the S3 vault on the middle level under the stairs to the top level (see figure below). If all the modules seem to be running properly, but the problem persists, contact the operators in Control Room, ext. 305.
+{{:wiki:power-supply-magnets.jpg?450|Power supply modules}}
   * Open the NCS PanelMate application and load file **THallps.ui**, in directory \\exp\files\control\ncsdata\General\Qt\Templates.
@@ Line 40: / Line 43: @@
-  * **Troubleshooting**: if a power supply cannot be turned on from PanelMate, check that the power supply module is ON. The modules for all S800 magnets are located in the S3 vault on the middle level under the stairs to the top level (see figure below).
-{{:wiki:power-supply-magnets.jpg?600|Power supply modules}}
 ===== Set S800 magnets settings =====
@@ Line 70: / Line 70: @@
 =====  Turn on the trim coils of the Spectrograph dipoles =====
+Note: The following procedure describes how to set the trim-coil currents manually. In principle, it is no longer necessary because Barney sets the currents automatically once the rigidity of segment 8 has been entered.
        * Check the currents in the Spectrograph dipoles by looking at the EPICS channels I265DS and I269DS. This can be done e.g. by clicking the button **Details** in segment 8 of the S800 Barney page (see figure below)

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