Alpha Technologies 255A Bypass Switch - Manual (Page 8)

0200018-J0 Rev C 6
The Alpha MBS is a manually operated mechanical switch for use with the Alpha series of Uninterruptible
Power Supplies (UPS). It provides a simple and effective means for bypassing uninterruptible power sup-
plies (UPS) while maintaining continuity of power to critical loads. (A schematic at the end of the manual
shows the MBS with the Alpha AMPS80 HP power system.)
Normally the output to the critical load is powered by the UPS with the bypass switch in the NORMAL
(UPS) position. Before the UPS is taken off-line for service or maintenance, the bypass switch can be
switched to the BYPASS position and the critical loads then receive power directly from the utility supply.
The Alpha MBS includes the following safety features:
• Phase detector with lock out
• Safe-to-switch (IN PHASE) lamp
• Electromechanical manual override
• Auxiliary contacts for remote monitoring
• Padlock bar for lockout
3. Features
3.1 Phase Detector with Lock-out
Bypass mode is enabled when UTILITY IN is within plus or minus 15 degrees of UPS OUT. The phase
difference is displayed in the phase meter at the bottom of the front panel in the range 0-360°.
15°
345°
In Phase Bypass Enabled
Manual switch
Bar for lockout
with a padlock
Phase meter
IN PHASE lamp
Electro-mechanical
key-operated switch