Output Connections
Output 24 VDC is supplied to components within the Maxum II via a cable harness that exits
the backside of the PSM. The cable terminates in quick disconnect connectors. Typically, a
white connector supplies 24 volts to the SYSCON2.1 cage and an orange connector supplies
24 volts to the PECM, where it is distributed to various modules in the EC. DC/DC converters
in the modules generate the other voltage levels needed by various circuits.
Fuse Replacement
The Power System Module is equipped with a fuse (Siemens Part Number A6X19905350).
This fuse is located on the front of the PSM just above the power cord plug. The fuse is a 250
V, 4.0 A, “slow-acting” type. Although this fuse rarely fails, replacement is simple (disconnect
power to the analyzer first). To remove the fuse, unplug the power cable that comes from the
PECM. Access the fuse by removing the fuse cap with a large blunt screwdriver.
Specifications
Voltage Range
115 VAC (85 to 140 VAC), 230 VAC (185 to 264 VAC)
Line Frequency Range
47 to 63 Hz
Nominal Input Current
2 amp @ 115 VAC, 1 amp @ 230 VAC
Nominal Output Voltage
24 VDC ±3%, 1% ripple plus noise at a bandwidth of 30 MHz
Nominal Output Current
6 A @ < 104°F (40°C)
4 A @ 104° to 150°F (40° to 70° C)
Static Load
0.2 A; 0.0 A open circuit permitted
Dynamic Load
Between 0.2 A to 3 A in the load range. A maximum load of 2 A at 1.8 kHz is
switched. Switching is controlled by pulse width. Precision range is not exceeded
in this operational mode.
Overcurrent Cutoff
Cutoff starts at 6.4 to 7.5 amps. When current drops, device switches on.
Overvoltage Cutoff
Cutoff starts at 27 to 31 VDC. When voltage drops, device switches on.
Overtemperature Cutoff
After temperature decreases to specified tolerance, device switches on.
Power Fail Transitions
Occurs 20 ms after a primary power failure. Should a power failure occur, a low
20 ms signal is generated.
Electric Isolation
Input/Output: 3.7 kV
Dimensions
Length: 10.24 inches (260 mm)
Width: 2.36 inches (60 mm)
Depth: 3.54 inches (90 mm)
Cooling
Convection and conduction through aluminum mounting plate.
Output Wiring
Cable harness
Electronic Compartment Component Descriptions and Maintenance Procedures
2.1 Power Supplies
Maxum II Reference Manual
14
Manual, 7/2017, 2000596-001