General Description
This modular system has been designed specifically to power 48V telecommunications equipment requiring
accurate temperature compensated Float and Equalisation voltages, low output
noise and EMI levels.
A typical system comprises a number of rectifiers, depending on the
power requirement of the system, and a monitoring and control subsystem
comprising a monitoring and control module (MiniCSU-2), a User Interface Board
(MUIB 2) and optional modules for monitoring AC power and battery cell
voltages.
The system can be configured in a number of ways depending on the
customer and application requirements.
The simplest option is shown in Figure 1.0
The AC Distribution may simply consist of circuit breakers, one for
each rectifier in the magazine depending on customer requirements along with
the single phase monitoring card to monitor ac voltage and it is connected via
a 16 pin ribbon cable with MUIB.
The rectifiers housed in one or more magazines are paralleled and the
DC output connected to the load via the DC Distribution module and to the
battery bank, which may be a single battery or two (or three) batteries
connected in parallel. A Low Voltage Disconnect Switch (LVDS) has also be
included in series with the batteries in order to prevent over-discharging the
battery bank in the event of an unusually long AC power outage.
The monitoring and control signals, such as battery currents,
temperature, batteries switch status, LVDS control and status, system voltage
and ambient temperature are connected to the monitoring and control module
(MiniCSU-2) via an interface card (MUIB-2). This module is in turn
connected to the MiniCSU-2 magazine via a 34 way ribbon cable and 16 way ribbon
cable.
A 3-wire cable, which carries the digital communications signals that
allow control and monitoring of the rectifiers, connects the MiniCSU-2 to all
the rectifiers in a parallel arrangement so that all the rectifiers receive the
same signal.
System status and operating parameters can be accessed from a PC
connected to local communication port on the front panel of the controller.
Remote monitoring of the system can be by means of voltage-free relay
contacts. System uses 2 relays to convey DC output fails, DC output over
voltage/under voltage, Mains fail.
Boost Charge operation
The boost charge mode becomes available when at least SMR 1 and one
battery switch are in boost charge operation. At any other case menus for this
mode (located in Battery section between Equalisation section and LVDS) will be
hidden. Adjustable parameters are voltage and current. If more than one SMR are
diverted to Boost BUS MiniCSU 2 will divide selected current by no. of
rectifiers.To start Boost Charge the push-button ENT must be pressed. MiniCSU 2
will perform passive sharing adjustment of the split system.
Boost charge mode is indicated on controller by continous yellow LED
and a message “BOOST CHARGE” alternating with the home display. On the
rectifiers yellow LED is lit continuously. The Boost charge mode will be
terminated when:
-
while viewing menu “stop chg mode” ENT key is
pressed.
-
Batteries are switched back to system bus
-
All SMRs used for Boost charge are switched back to
system bus
After
termination of the Boost charge mode and return of all SMRs to system BUS
Controller will perform active sharing of all the modules.
A typical mechanical arrangement of a system comprising 4 rectifiers is
shown in Fig 0.2. It consists of a
rectifier magazine (6U) with provision for air intake (4U) and exhaust (3U) for
the rectifiers which are cooled by natural convection. A 1U high shelf
accommodates the MiniCSU-2, MUIB-2 & ISAM cardsThe arrangement shown is
designed to fit into a standard 19” rack or can be fitted with side flanges for
wall mounting. A combined AC and DC distribution module completes the system.
Typical
3 rectifier modular power supply
Figure 0.2 Typical 4-rectifier
modular power supply
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