SPRING-GUIDE 3056843 - Caterpillar

Engines: 3304 (S/N: 02B4226-UP; 5CA1-UP) 3306 (S/N: 70R8891-UP) 3406 (S/N: 90U1-UP) 3408 (S/N: 67U1-11134; 78Z1-1143) 3408B (S/N: 67U11135-16070; 78Z1144-4866) 3408C (S/N: 67U16071-UP; 78Z4867-UP) 3412 (S/N: 38S1-16483; 81Z1-14500) 3412C (S/N: 38S16484-UP; 81Z14501-UP) 3508 (S/N: 23Z1-UP; 70Z1-UP) 3512 (S/N: 24Z1-UP; 67Z1-UP) 3516 (S/N: 25Z1-UP; 73Z1-UP) D330C (S/N: 02B1-4225) D333C (S/N: 62M1-UP; 70R1-8890)Introduction
This Special Instruction contains the procedure for determining and replacing faulty transformers in the automatic transfer switch. The new 184-2461 Transformer Kit consists of four transformers (NT2, NT3, NT4 and ET2) and eight self-tapping machine screws.Transformers NT2, NT3 and NT4 monitor the line voltages under the normal condition. Transformer ET2 along with adjacently mounted transformers ET3 and ET4 monitor the line voltages under the emergency conditions. If one of transformers NT2, NT3, NT4 or ET2 has failed, the automatic transfer switch will not transfer to the power source monitored by the faulty transformer(s).
Table 1
Tools Needed    
Part Number    Description    
184-2461     Transformer Kit    
    AMP Pin Extraction Tool (AMP part number 318851-1)    
    Drill    
    3.2 mm (1/8 inch) drill bit    
    Screwdriver    Reference: Service Manual, SENR2164, "Transfer Switches".Determining Faulty Transformer
Checking Transformer NT2
Ensure that the transfer switch is set for NORMAL automatic operation.
Follow the black and white leads on transformer NT2 back to their termination points. Check for 120 ACV. If the voltage is present, check for 24 ACV across terminals 1 and 2 on the logic package. Check for 12 ACV across terminals 1 and 3. Check for 12 ACV across terminals 2 and 3 on the logic package. See Illustration 1.Expected Result: The voltages are present.Results:
YES - The voltages are present. Go to 2.
NO - Any of these voltages are not present. Transformer NT2 has failed. After checking transformers NT3, NT4 and ET2, proceed to ""Replacing Transformer(s)"".
Illustration 1 g00677354
The logic package
Checking Transformer NT3
Ensure that the transfer switch is set for NORMAL automatic operation.
Check for 12 ACV across the yellow leads on terminals 4 and 5 on the logic package.Expected Result: The voltage is present.Results:
YES - The voltage is present. Go to 3.
NO - The voltage is not present. Transformer NT3 has failed. After checking transformers NT4 and ET2, proceed to ""Replacing Transformer(s)"".
Checking Transformer NT4
Ensure that the transfer switch is set for NORMAL automatic operation.
Check for 12 ACV across the yellow leads on terminals 6 and 7 on the logic package.Expected Result: The voltage is present.Results:
YES - The voltage is present. Go to 4.
NO - The voltage is not present. Transformer NT4 has failed. After checking transformer ET2, proceed to ""Replacing Transformer(s)"".
Checking Transformer ET2
Ensure that the transfer switch is set for NORMAL automatic operation.
Check for 24 ACV across terminals 8 and 9 on the logic package. Check for 12 ACV across terminals 8 and 10 on the logic package. Check for 12 ACV across terminals 9 and 10 on the logic package.Expected Result: The voltages are present.Results:
YES - The voltages are present. Therefore, the fault may be intermittent. Check all the electrical connections. If the problem still exists, repeat the entire