Lake Shore 625, User Manual

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Lake Shore Model 625 Superconducting MPS User’s Manual
7-2 Service
7.3 FUSE DRAWER
The Model 625 may be configured for two basic AC power configurations: 100 or 120 VAC and 220 or 240 VAC. Each
configuration requires the appropriate fuses and fuse holder. Units produced for use with 100 or 120 VAC have two
0.25
× 1.25 inch time-delay fuses and the appropriate fuse holder installed. Units produced for use with 220 or 240 VAC
have two 5 × 20 mm time-delay fuses and the appropriate fuse holder installed. To change the AC power configuration
from the factory setting, use the fuses and fuse holder in the connector kit shipped with the instrument. The Model 625
requires two good fuses of the same rating to operate safely. Refer to Paragraph 7.5 for details.
625_Fuse_Open.bmp
Figure 7-1. Fuse Drawer
7.4 LINE VOLTAGE SELECTION
Use the following procedure to change the instrument line voltage selector. Verify the fuse value and drawer whenever
the line voltage is changed.
WARNING: To avoid potentially lethal shocks, turn off the power supply and disconnect it from AC power before
performing this procedure.
1. Identify the line input assembly on the instrument rear panel. See Figure 7-2.
2. Turn the front panel line power switch OFF (
O
).
3. Remove the instrument power cord.
4. With a small screwdriver, release the drawer holding the line voltage selector and fuses.
5. Slide out the removable line voltage selector from the drawer.
6. Rotate the line voltage selector until the proper voltage indicator shows through the window.
7. Verify the proper fuse value and fuse drawer.
8. Re-assemble the line input assembly in the reverse order.
9. Verify the voltage indicator in the window of the line input assembly.
10. Connect the instrument power cord.
11. Turn the front panel line power switch On ( l ).