APC VS 50 User Manual

Page of 65
Magnum VS –48 Vdc User’s Manual 
 
Page 20 
5 Technical 
Description 
 
The Power System is designed to supply safe –54 Vdc primary power through the use of up to 
10 rectifier modules.  The controller will monitor all functions and provides battery management 
including controlled battery recharge with temperature compensation and low voltage 
disconnect.  Integrated dc output distribution supports loads ranging from ¼ A all the way to 60 
A.  The controller can monitor up to 4 discrete external events with voltage free (“dry contact”) 
user inputs. 
 
5.1. Rectifier Management 
 
AC Input Power 
 
The basic component of the power system is the rectifier module, which rectifies utility ac into 
nominal 48 Vdc. Each rectifier module requires 85 – 264 Vac, 47 – 63 Hz single phase power.    
Available cord sets include a variety of blade and twist lock plugs.  Dedicated wiring inside 
conduit can also be used.  
 
DC Output Power 
 
The dc outputs of all the rectifiers in the system are connected to a common bus that is rated to 
carry the current of the entire system.  The rectifier modules will equally share the entire load, 
independent of the controller. The rectifiers will continue to provide dc power (-54.5Vdc) if the 
controller is removed or fails. 
 
Rectifier alarms reporting 
 
The rectifier has numerous sensors inside the unit that monitor fan fail, high temperature, 
high/low voltage, etc.  These rectifier sensors trigger outputs that are monitored by the 
controller.  In addition rectifier current is measured inside each rectifier.  The controller can 
trigger output relays in the event of a rectifier alarm. Refer to Section 5.5 for controller functions.  
 
5.2. System Management 
 
System Voltage Monitor and Control 
 
The controller monitors and adjusts the system voltage.  It uses a voltage trim input to the 
rectifier to precisely control the dc output voltage.  In the event of controller removal or failure, 
individual rectifiers will default to the analog voltage level (-54.5 Vdc) preset at the factory.  
System high and low voltage alarms are reported by the controller.