Powerware 5075 kVA - Manual (Page 73)

65 Powerware BPIII Harsh Environment UPS 50--75 kVA Installation and Operatio n
164201261 Rev. F 111503
• The START switch activates the power controls on the Control Panel. The
START switch is center-biased (the key will rest only in the upright position). Its
operation is similar to that of an automobile ignition switch. After setting the
operator controls, you turn the START switch to the right momentarily to
activate the controls. When you release it, it returns to the upright position.
The following paragraphs describe the controls and indicators found in the
Environmental cabinet (see Figure 33).
• The circuit breaker (CB1) switch supplies power to the rectifier and inverter. If
CB1 is on (closed), the rectifier turns on when the START switch is activated
and the proper voltage is at the input terminals.
• The circuit breaker (CB2) switch controls the application of battery power to the
UPS. If CB2 is closed, the rectifier charges the battery through the DC to DC
converter during normal operation. If utility power is lost, battery power is
supplied to the inverter through the DC to DC converter.
S
Maintenance Bypass (MBP) Circuit Breaker --- This breaker is
normally open. When closed, it feeds utility power to the critical load
when the MIS breaker is opened.
S
Maintenance Isolation (MIS) Circuit Breaker --- This circuit breaker
is normally closed, feeding UPS power to the critical load. This
breaker is opened to isolate the UPS after the MBP breaker is
closed.
S
Bypass Input (BIB) Circuit Breaker --- This circuit breaker is
normally closed feeding bypass power to the UPS internal bypass
circuit. This breaker is opened to isolate the UPS bypass after the
load is transferred to maintenance bypass.