BRIDGE-VALVE 3487743 - Caterpillar

Version 1 Hardware
There are four control transformers located in the 4-Wire Transformer cabinet.Two of the transformers (T12 and T13) are located on the left panel and two of the transformers (T14 and T15) are located on the right panel.Transformers T12, T13, and T14 are used to operate the three fans in the cabinet.Transformer T15 is used to power the 4-Wire Thermal Switch Monitor Board located on the fan plenum shield. The thermistors for T12 to T15 are located on the bottom side of the transformer, as installed. All thermistors are connected to the H1 and to the H2 or COM connectors of the transformer. The thermistors limit the in-rush current on power-up.
Illustration 1 g01326743
4-Wire Transformer Cabinet Left Panel - Version 1 (1) Transformer T12 (2) Transformer T13
Illustration 2 g01326746
4-Wire Transformer Cabinet Right Panel - Version 1 (3) Transformer T14 (4) Transformer T15Version 2 Hardware
There are five control transformers located in the 4-Wire Transformer cabinet.The transformers are located along the top rail of the cabinet in the front.Transformers T12, T13, T14, and T16 are used to operate the four fans in the cabinet.Transformer T15 is used to power the 4-Wire Thermal Switch Monitor Board located on the top component panel.The thermistors for T12 to T16 are located on the top of the transformer, as installed. All thermistors are connected to the H1 and to the H2 or COM connectors of the transformer. The thermistors limit the inrush current on power up.
Illustration 3 g01272200
Transformer location, version 2 hardware (1) Transformer T12 (2) Transformer T13 (3) Transformer T14 (4) Transformer T15 (5) Transformer T16
Table 1
Thermistor Specifications    
    Size     Ohm    
T12     32mm     20 ohms at
25 °C (77 °F)    
T13     32mm     20 ohms at
25 °C (77 °F)    
T14     32mm     20 ohms at
25 °C (77 °F)    
T15     32mm     20 ohms at
25 °C (77 °F)    
T16     32mm     20 ohms at
25 °C (77 °F)    
Table 2
Transformer Specifications    
   Input (V)    Output (V)    Wire Gauge (AWG)    
T12     380, 400, 415, 440, 480     230     H=12-22
X=10-18    
T13     380, 400, 415, 440, 480     230     H=12-22
X=10-18    
T14     380, 400, 415, 440, 480     230     H=12-22
X=10-18    
T15     380, 400, 415, 440, 480     21     H=12-22
X=10-18    
T16     380, 400, 415, 440, 480     230     H=12-22
X=10-18    Thermistor Removal
Illustration 4 g01272219
T12 - T15 Transformer Wire Connections, version 1 hardware (1) Transformer T12 (2) Transformer T13 (3) Transformer T14 (4) Transformer T15 (6) Thermistor
Illustration 5 g01272221
T12 - T16 Transformer Wire Connections, version 2 hardware (1) Transformer T12 (2) Transformer T13 (3) Transformer T14 (4) Transformer T15 (5) Transformer T16 (6) Thermistor
Perform steps in the Systems Operation, Testing and Adjusting, "Internal Component Preremoval Steps (4 Wire Transformer Cabinet)" in order to de-energize the system and gain access to internal components.
Loosen the two screws and pull the thermistor (6) free of the terminal block. Each thermistor (6) is attached by two screws