Toshiba AUXILIARY CABINET 431M - Manual (Page 56)

48 4300 Series Ancillary Cabinets Installation and Operation Manual
12.8 MBS Operation
Switch MBS from on-line to Bypass (Solid lines)
The 431M Mechanical Interlock Plate is locked in the On-Line position by a solenoid. When the UPS is
placed in Static Bypass mode, the light on the front of the MBS lights and the interlock solenoid retracts
and allows the Mechanical Interlock Plate to be moved. See Figure 12-8.
1. Place the UPS in static bypass. The Bypass indicator light on the 431M should illuminate and the
interlock solenoid will retract.
NOTE: If the Bypass indicator light DOES NOT ILLUMINATE in bypass mode, contact Toshiba Field
Service immediately.
2. Slide the Mechanical Interlock Plate to the center position as shown in Figure 12-8 B.
3. Switch CB2 ON (up) as shown in Figure 12-8 C.
4. Switch CB3 OFF (down) and CB1 OFF (down), as shown in Figure 12-8 D.
5. Slide the mechanical Interlock Plate to the left position as shown in Figure 12-8 E.
6. The circuit breakers are now locked in Maintenance Bypass position.
Switch MBS from Bypass to On-Line (Dotted lines)
1. The Maintenance Bypass position is shown in Figure 12-8 E. The UPS should be in static bypass
mode, and the MBS indicator light should be illuminated.
2. Slide the mechanical Interlock Plate right to the Center position as shown in Figure 12-8 D.
3. Switch in order, CB1 ON (up), and CB3 ON (up) as shown in Figure 12-8 C.
4. Switch CB2 OFF (down), as shown in Figure 12-8 B.
5. Slide the mechanical Interlock Plate to the right position as shown in Figure 12-8 A.
6. Place the UPS in On-Line mode.
7. The MBS indicator light should extinguish, and the MBS solenoid locks the Mechanical Interlock Plate
in place.
Figure 12-8 - MBS Mechanical Interlock Plate Operation
CB3
Maintenance Bypass to On-Line
CB1
CB2
(C) (E) (A) (B)
On-Line to Maintenance Bypass
CB3
(D)