VALVE GP-RELIEF 9T8378 - Caterpillar

Multiple Module System (MMS)
The MMS is different from the SMS. The MMS contains an MMU Cabinet, an Input/Output Cabinet, and a System Cabinet. The MMS is an expandable ready system. An MMU can be added to a system if an expanded run time or a higher power requirement is present.MMS (N+1)
The optional (N+1) system is equipped with an additional MMU. In this configuration, the loss of one MMU will not cause the system to drop the critical load. When a malfunction occurs in the MMU, the MMU will be disconnected from the critical load. The remaining MMUs will continue to carry the load. After the MMUs have been repaired, the units can be reconnected to the critical load and the units can resume redundant operation. The load will automatically transfer the bypass line without interruption if the following conditions occur: removal of the MMUs from the system and exceeded load capacity of the MMUs. Any redundant MMUs can manually be removed from the critical load for maintenance without disturbing the critical load bus. In this case, the isolation switches are used.Cabinets
The components of the UPS are contained in steel cabinets. The systems consist of following cabinets:
The Input/Output Cabinet
The System Cabinet
Flywheel Cabinet
The MMU CabinetsThe cabinets are transported as individual units. The units are delivered separately. The units are assembled at the site of installation. The Input/Output Cabinet weighs 590 kg (1300 lb). The System Cabinet weighs 386 kg (850 lb). The MMU Cabinet weighs 2041 kg (4500 lb).Table 1 describes the configuration of each type of system.
Table 1
STANDARD SYSTEMS    
System     Included Cabinet     Quantity    
UPS 250/300
Expandable     Multiple Module Unit Cabinet     1    
System Cabinet 1    
Input/Output Cabinet 1    
UPS 500/600     Multiple Module Unit Cabinet     2    
System Cabinet 1    
Input/Output Cabinet 1    
UPS 750/900     Multiple Module Unit Cabinet     3    
System Cabinet 1    
Input/Output Cabinet 1    
REDUNDANT SYSTEMS (N+1)    
System     Included Cabinet     Quantity    
UPS 250/300 Expandable (N+1)     Multiple Module Unit Cabinet     2    
System Cabinet 1    
Input/Output Cabinet 1    
UPS 500/600 (N+1)     Multiple Module Unit Cabinet     3    
System Cabinet 1    
Input/Output Cabinet 1    
UPS 750/900 (N+1)     Multiple Module Unit Cabinet     4    
System Cabinet 1    
Input/Output Cabinet 1    Theory of Operation
Simplified block diagrams of the system are represented by illustration 1 through illustration 2. The nodes determine the state of the system. The input node and the output node are externally available. These nodes are used in order to attach the system to a power source and to the load. The inverter node is used internally by the system. The DC bus