Owner`s manual

4.5 DC Input Power Connections
The “Receiver” cabinet also contains the DC distribution bus bar system, which is called a “DC Raceway”. It
consists of a sheet metal enclosure with two copper bus bars, 1.5” wide, 0.125” thick. These bus bars have ELCON
connectors attached to them. The “power modules” have short bus bars projecting out the back of the chassis,
which supply the power to the module. These bus bars plug into the ELCON connectors. DC input wiring connec-
tions to the bus bars is in the “static switch” area. They are set up to accommodate three positive wires and three
negative wires of 2/0 or smaller gauge wire, terminated with two-hole lugs. Wiring to the “receiver” rack should be
by the “super flexible”, welding cable type wire for the five or six “power module” systems, standard wire for the one
to four “power module” systems. Within the “static switch” area, the negative bus bar passes through a “LEM” open
loop DC current sensor, HTA type. In a system, which has redundant “processors”, there will be two current sensors.
The model number of the “LEM” current sensors change, depending upon the number of “power module” positions
in the “receiver” rack. The “Controller” needs to be set up at the time of installation. This set up will be by a “lap
top” personal computer (PC) and field service software.
4.6 Inverter AC Output Distribution
The AC Raceway contains connectors for interfacing to the “power modules”. It consists of one or two printed circuit
boards housed in a sheet metal enclosure. These PCBs have the inverter AC output filter capacitors. These capac-
itors are connected to the AC output terminals and rated at 50uF, 250V, one capacitor for each 120VAC “power
module” output. Power output and control of the power module is through a rack and panel connector. These
connectors, one per power module position, have the control and AC output wires. Two 16Awg wires are paralleled
for each 120VAC output and return. AC output wires are identified as “120VAC” and “NEUTRAL” for the master
inverter, “ACHI” and “ACLO” for the 120V slave inverter. The output of these PCBs are connected to the EMI by
means of 10Awg colored wire. Neutral is “white”, 120VAC is “black”, ACLO is “blue”, ACHI is “red”. These wires
eventually end up connecting to the “EMI” filters, there being two 120VAC filters. “120VAC” and “Neutral” connect
to the bottom EMI filter, and “ACHI” and “ACLO” connect to the upper EMI filter. The output of the filters are
connected either in parallel to produce 120VAC or series to produce 240VAC. Copper straps perform this function
and easily changed by the user. The inverter is shipped from the factory connected for 120VAC, 60Hz operation.
The “AC raceway” PCB is connected to the “Controller” back plain via ribbon cable and also to the second PCB in
a two to six “power module” system. The “AC race way” has cover plates which will aid in EMI reduction and also
prevent service personal from making inadvertent contact with live power wires.
4.7 Power Modules
The power modules are self-contained DC to AC inverters, minus the output filter capacitors and control circuitry
(which is located on the “Controller” boards). These “power modules” should be viewed as voltage controlled
current sources (or sinks). The front panel of the power module has a 100A DC circuit breaker, which is used to
turn the power module ON and OFF. This is located on the top left-hand side of the front panel. The center has a
fan guard, which covers the air intake of a 24VDC cooling fan. The fan is operated at reduced voltage, 14V, so as
to increase bearing life. At elevated ambient, greater than 55C, full voltage is applied to the fan. The lower right
side of the power module has three “LEDs” to indicate the status of the module. The LED closest to the center of
the unit is a RED/GREEN indicator. When the module is turned ON, the LED will be GREEN if the power module
can function properly. If it turns RED, the module has a faulted. Faults are usually due to the power module not
providing the proper output current, or the internal DC voltages are to high, or the module is over temperature.
There are two “Temperature” LEDs located to the right of the RED/GREEN status LED. The center LED is AMBER,
which will light if the internal heat sink temperature is to high, greater than 77C. The far right side LED is a RED
and will light if the internal heat sink temperature is excessively high, greater than 88C. When this LED lights, the
power module will shut down and disconnect itself from the system. The power module “status” indicator will also
turn RED. Over temperature Red LED will remain illuminated until the DC circuit breaker is turned OFF. Fan sped
control, temperature warning, and over temperature indications are by mechanical temperature switches.
3.5 to 21 kVA N+1 Inverter
Theory of Operationpage 4 — 4