Supported Platforms
MX2020 AC Power Supply Module Description
There are a total of eighteen AC power supply modules (PSMs) located at the rear of the chassis in slots PSM0 through PSM8 (bottom), and slots PSM9 through PSM17 (top) (left to right). Here is a breakdown of the AC power distribution:
- The AC PSMs in slots PSM0 through PSM8 provide power to the lower fan trays (0, 1, and upper 2), and MPCs in slot 0 through 9, CB-REs in slot 0 and 1, and SFBs in slot 0 through 7.
- The AC PSMs in slots PSM9 through PSM17 provide power to the upper fan trays upper (2, 3, and lower 0), and MPCs in slot 10 through 19, CB-REs in slot 0 and slot 1, and SFBs in slot 0 through 7.
The MX2000 line of routers supports a three-phase delta AC power system, a three-phase wye AC power system, or a single-phase AC power system.
 | Caution: Do not mix AC and DC PSMs or different PDM types within a single system. The MX2000 line of routers configured for three-phase wye AC input power must use only three-phase wye AC PDMs and three-phase wye AC PSMs. The systems configured for three-phase delta AC input power must use only three-phase delta AC PDMs and three-phase delta AC PSMs. The systems configured for single-phase AC input power must use only single-phase AC PDMs and single-phase AC PSMs. |
In a three-phase AC power system, the AC power going to the PSMs is split into a pair of phases. Each PSM works on a single phase. This means the power system works independent of the kind of AC feed connected. You can connect one or two feeds, depending on the power system configuration, number of PSMs, redundancy, and so on. Each phase from each of the two feeds is distributed among one or two PSMs. One feed has each phase going to two PSMs and the other feed has each phase going to a single PSM. The PDM can receive up to six different phases for distribution among nine AC PSMs.
The AC PSMs are hot-removable and hot-insertable.
Up to nine PSMs may be connected in parallel per power subsystem to increase available power for MPCs, as needed and to provide redundancy. Figure 1 shows the AC PSM.
Figure 1: AC Power Supply Module
The AC power system provides dual redundant feeds (INP0 and INP1). Each PSM takes in two AC feeds and uses one of the two. Only one feed is active during power operation. Each feed is a single phase AC system 200-240 VAC derived from a three-phase delta or three-phase wye AC input system. These feeds are set by the input mode DIP switch located on the AC PSM. Move the input mode DIP switch to the on or off position to determine the power supply feeds (see Table 1 and Figure 2).
Table 1: DIP Switch Positions on the AC PSM
Left Switch Position | Right Switch Position | Input Source |
|---|---|---|
Off | Off | None |
On | Off | Input 0 (INP0) |
Off | On | Input 1 (INP1) |
On | On | Both Input 0 and Input 1 |
Figure 2: Selecting Input Feed on the AC Power Supply Module
A PSM failure triggers the alarm LED on the craft interface. Each PDM has an LED per feed indicating whether the feed is active or whether the feed is properly connected properly. For information about connecting to AC power sources, see MX2020 AC Power Subsystem Electrical Specifications.
