1-32
Chapter 1
Overview
UPS Modes
UPS Modes
The UPS has four modes of operation:
On-line, On-battery, Automatic Bypass,
and
Service
Bypass.
On-line Mode
When the UPS is operating normally, it is in On-line mode. In this mode, it is monitoring
the AC input line and providing AC power to the output receptacles.
AC input power enters the Electronics Unit through the MAIN circuit breaker in the
Service Bypass Unit (SBU). Power is directed to the Electronics Unit where it is monitored
and returned to the SBU. See Figure 1-10. AC power then passes through the Service
Bypass switch, which is in the NORMAL position, to the Output Breakers, and on to the
output receptacles.
In this mode, AC input power to the Electronics Unit is also used to charge the batteries, if
required.
On-battery Mode
If AC input power is interrupted when the UPS is operating normally, the UPS switches to
On-battery mode. In this mode, the batteries supply DC power to the DC-AC inverter.
Output power flows to the Service Bypass Unit through the Service Bypass switch, which
is set to NORMAL, and on to the output receptacles. This mode is used to allow time to
safely shutdown the SPU or other loads. Fully charged batteries can sustain power to the
SPU and other connected equipment for up to 15 minutes.
CAUTION
Do not push the red button while the UPS is operating on battery. Damage to
the connected equipment can occur.
Automatic Bypass Mode
When the Electronics Unit detects an internal fault, it bypasses faulty or failing AC
circuitry so that AC input power continues to flow to the connected equipment. While in
Automatic Bypass mode,
the UPS remains surge protected. Loss of input power while the UPS
is in this mode, however, results in a complete loss of power to the connected equipment.
In this mode, AC input power flows through the Bypass breaker (see Figure 1-10) into the
Electronics Unit where it is routed directly to the Automatic Electronic Bypass switch,
which is closed, through the Service Bypass switch, which is set to NORMAL, and on to the
output breakers and receptacles.
Because the Electronics Unit has detected an internal fault, battery power to the
connected equipment is not available. If AC input power is interrupted while the UPS is in
this mode, output power will also be interrupted.
Summary of Contents for PowerTrust A3589A
Page 7: ...Contents Contents 5 ...
Page 8: ...Contents 6 Contents ...
Page 10: ...Contents 8 Figures ...
Page 12: ...Contents 10 Tables ...
Page 14: ...2 ...
Page 20: ...Preface 8 ...
Page 22: ...Preface 10 ...
Page 52: ...1 30 Chapter1 Overview Specifications Figure 1 8 UPS Input Voltage Transfer Points ...
Page 56: ...1 34 Chapter1 Overview UPS Modes Figure 1 10 Simplified UPS 5 5 kVA UPS Block Diagram ...
Page 62: ...1 40 Chapter1 Overview Support Information ...
Page 76: ...2 14 Chapter2 Unpacking and Inspecting Shipping and Storage Requirements ...
Page 104: ...3 28 Chapter3 Installing the UPS Examples of PowerTrust Connections in a System ...
Page 116: ...5 4 Chapter5 Verification Procedures Load Testing ...
Page 148: ...7 6 Chapter7 Cleaning and Maintenance Exchanging Batteries Fan ...
Page 190: ...A 42 AppendixA HP UX UPS Monitor Error Messages Log Only Messages ...
Page 218: ...C 8 AppendixC Configuring the OS for the PowerTrust UPS Power Failing the UPS ...