Lakeshore Learning Materials 642 - Manual (Page 95)

Lake Shore Model 642 Electromagnet Power Supply User’s Manual
Service 7-3
TERMINAL SCREW
WIRE FERRULE
VOLTAGE SELECTOR CARD
VOLTAGE INDICATOR KEY
Figure 7-2. Voltage Change Detail
7.4 CIRCUIT BREAKER SETTING
The main three-phase input power is protected by an automatic-reset circuit breaker within the instrument. A smaller,
start-up power supply is fused separately and discussed in Section 7.5. If the breaker trips, it will reset within a few
minutes and the unit can be restarted. If the unit trips again after a short time, the circuit breaker trip current may be set
incorrectly. Table 7-1 shows required voltage and current settings.
Table 7-1. Voltage and Current Selection
Nominal Voltage Voltage Tap Circuit Breaker
200 V 204 V 18 A
208 V 204 V 18 A
220 V 225 V 17 A
230 V 225 V 17 A
380 V 380 V 12 A
400 V 408 V 12 A
415 V 408 V 12 A
WARNING: To avoid potentially lethal shocks, turn off the power supply and disconnect it from AC power before
performing this procedure.
CAUTION: For continued protection against fire hazard, use only the recommended current setting for the line
voltage selected.
Use the following procedure to verify or change the circuit breaker current setting.
1. Identify the power wiring access panel on the rear of the Model 642.
2. Turn the front panel line power switch OFF (O).
3. Disconnect the power cable at the plug end for safety.
4. Remove the perimeter screws holding the power wiring access panel.
5. Refer to Figure 7-1 to locate the circuit breaker detailed in Figure 7-3.
6. Lift the circuit breaker setting access door and visually confirm the setting as shown in Figure 7-3.