Power Supply
The SG 2000 power supply (SG2-PS2) is located in the housing lid to optimize heat transfer and to balance the thermal load between the base and the lid. For high reliability or redundancy applications, two power supplies can be used. An umbilical cord connects the SG2-PS2 to the lid motherboard (LIDB).
A flexible power-distribution design enables you to power the node from any of the four RF ports. Using fuses and shunts you can configure the node to distribute power to the remaining active ports. You can also power the node locally through the ac only port (port 2) while a second cable-plant power supply loops through the other two main RF ports.
The power supply includes a heavy-duty, gas discharge tube surge protector located on the amplifier module. You can replace this surge protector with the optional FTEC surge protector. The FTEC triggers at approximately 230 V and presents a short circuit to the line during periods of over voltage. After the ac input voltage returns to normal, the FTEC returns to its open-circuit state. This provides the node with a level of protection against surge currents on the ac line. The same protector is used for both supplies unless the split ac-feed option is implemented; then, the secondary or redundant power supply is protected by a conventional heavy-duty gas discharge tube.
The 20-ampere fuses are installed at the factory to provide power passing to additional amplifiers. Section 3, “Bench Setup,” discusses fusing options that are also diagrammed in Figure 3-1. Figure 3-2 illustrates the location of the fuses.
The SG 2000 optical node can be powered from either 60 Vac or 90 Vac system power supplies. The unit is shipped from the factory set for 60 Vac powering. For systems equipped with 90 Vac powering, the suitcase jumper on the dc power supply can be repositioned to optimize the supply start-up voltage for the higher input range. Section 3, “Bench Setup” provides a description of this procedure.
Figure 2-4 illustrates the SG2-PS2 power supply:
Figure 2-4
SG2-PS2 power supply
SG2-PS2
NO USER SERVICEABLE PARTS INSIDE | | | | | | ASSEMBLED IN MEXICO |
CAUTION | | | | | | | 24V | | 5V |
| | | | | | |
VOLTAGE S IN EXCESS OF | | | | | | | | | | |
300 VOLTS ARE PRESENT | | | | | | | | | | |
UNDER COVE R AND MAY | | | | | | | | | | |
BE PRESENT AFTER POWER | | | | | ADJ | | | |
IS REMOVED | | | | | | TEST |
SEE INSTALLATION MANUAL FOR SERVICE | LO | HI | | | TEST | |
| POINT | | POINT |
The optional SG2-PS power supply is required to support DS-SG2-DRT-2X/A transmitters in a redundant configuration. The SG2-PS2 and SG2-PS power supplies are interchangeable.
SG 2000 Installation and O peration Manual
