MP SERIES™ Battery Backup System for Traffic Signals: MP2000E System
Volume One: Operating Manual
Page 6-1
Section 6
Theory of Operation
6.a Systems Description
The Myers Emergency Power Systems MP2000E battery backup system (BBS) is comprised of
three main components, which are described in the subsections below.
6.a.1 MP2000E BBS Module
The BBS module has two main operating modes: On Line and On Battery.
•
O
N
L
INE
M
ODE
: When in On Line mode, the BBS functions as a line interactive back up
system. Line interactive BBS units are designed so that the inverter is always
connected to the output of the BBS. When line power is present, the inverter operates
in reverse to charge the battery. When utility power fails, the BBS reverses the power
flow from the inverter and provides power to the load. This design provides better
filtering than a standby unit because the inverter is always connected to the load.
The MP2000E also incorporates Buck and Boost, an automatic voltage regulator. Buck
and Boost allows the BBS to effectively step-up or step-down the incoming line voltage
without switching to battery power. This allows the BBS to correct most long term
over-voltages or under-voltages without draining the batteries. The Buck and Boost
features also extend the life of the batteries by reducing the number of transfers to
battery power.
•
O
N
B
ATTERY
M
ODE
: In On Battery Mode, the batteries supply direct current to the
MP2000E inverter. The BBS filters the DC input through input capacitors and metal
oxide silicon field effect transistors (MOSFET) that feeds a transformer that steps the
voltage up to 120 VAC. The 120VAC, 60Hz waveform generated by the MP2000E inverter
is a pure sine wave.
6.a.1.1 Operation Within On Battery Mode
•
F
ULL
I
NTERSECTION
O
PERATION
: The MP2000E is designed to supply full backup power
within the BBS rating.
•
R
ED
F
LASH
I
NTERSECTION
O
PERATION
: Intersections can be programmed to be in red flash
mode by wiring and programming any one of the six dry contacts on the MP2000E to
the traffic signal controller red flash circuit.
