Eaton Powerware 9395 Installation And Operation Manual - page 27
EATON Powerware
®
9390 and 9395 Sync Control Installation and Operation Manual
S 164201571 Rev E www.powerware.com
4−1
Chapter 4
Powerware Sync Control Operating Instructions
This chapter describes the operation of the Powerware Sync Control.
4.1
Startup for UPS Systems Equipped with a Powerware Sync Control
Startup and operational checks must be performed by an authorized Eaton Customer
Service Engineer, or the warranty terms as specified on page 5−1 become void. This
service is offered as part of the sales contract for the UPS. Contact service in advance
(usually a two−week notice is required) to reserve a preferred startup date.
4.2
Understanding Powerware Sync Control Operation
The Powerware Sync Control maintains critical load synchronization of either two
separate single Powerware 9390 UPS systems or two separate single Powerware
9395 UPS systems. See Figure 4-1 for a typical block diagram of the system.
Synchronization of the UPS systems facilitates the uninterrupted transfer of customer
loads from one load bus to another by means of downstream, dual−source, solid−state
transfer switches. Enable the automatic synchronization action of the Powerware
Sync Control by pressing the Load Sync Enable pushbutton on the front of the panel.
When enabled, the Load Sync Enable pushbutton illuminates.
The Powerware Sync Control panel provides a three−phase synchronization reference
to each system. Each system uses this reference to regulate the inverter phase
relationship so that the two system outputs can maintain synchronization with each
other. To establish the three−phase synchronization reference, each system provides
bypass sensing voltage and output (critical load) bus voltage to the Powerware Sync
Control.
Under normal operating conditions, bypass sensing voltage from each system is
provided back to its inverter through the Powerware Sync Control. As long as the two
bypass sources feeding UPS System−A and UPS System−B are available and in phase,
each system remains in synchronization with its own bypass source and the two
systems remain in synchronization with each other. If the two bypass sources
become out of phase with each other (>0.1 Hz apart) or one or both sources become
unavailable, the Powerware Sync Control provides a new three−phase synchronization
reference to the non−master system as determined by the Preferred Source Selector
switch. The non−master system’s new synchronization reference is provided by the
Powerware Sync Control from the output (critical load) bus of the system designated
as master by the Preferred Source Selector switch. See Figure 4-2 for a diagram of
the synchronization reference control operation.
When the two bypass sources regain availability and synchronization, the Powerware
Sync Control provides the non−master system with its own bypass sensing voltage as
a synchronization reference. Before resynchronization occurs, a 15−second preset
time delay ensures the two bypass sources maintain acceptable synchronization.
To maintain a fault−tolerant arrangement, the Powerware Sync Control accounts for
the following fault conditions or abnormal operating conditions:
Figure 4Table 4