Transformers are critical for keeping our nation running: without transformers, we wouldn’t have the electricity we need.
Consequently, it is crucial that transformers are properly assembled, tested and maintained in order to extend their lifespan. One significant part of transformer assembly and maintenance is ensuring that the lugs are torqued to the appropriate tension.
Below are the standard torque specs for Maddox transformers (all values in ft-lbs):
Table of standard torque specs for Maddox transformers
| Reference Level III |
Wrench |
Tolerance |
Minimum Tolerance |
Torque Value |
Maximum Tolerance |
Pad |
Pole |
| 71.2.8 |
Arrester Disconnect SW |
± 1.00 |
9.00 |
10.00 |
11.00 |
x |
x |
| 71.2.4 |
DV Switch |
± 1.00 |
9.00 |
10.00 |
11.00 |
x |
x |
| 71.2.9 |
Internal Fault Detector |
± 1.00 |
9.00 |
10.00 |
11.00 |
x |
x |
| 71.2.5 |
Tap Changer |
± 1.00 |
9.00 |
10.00 |
11.00 |
x |
x |
| 71.2.4.1 |
Neutral Disconnect |
± 1.00 |
9.00 |
10.00 |
11.00 |
x |
x |
| 71.4 |
HV Bushing Insert |
± 1.50 |
13.50 |
15.00 |
16.50 |
x |
- |
| 71.2.3 |
Bayonet |
± 1.67 |
14.99 |
16.66 |
18.33 |
x |
- |
| 71.2.8 |
Under Oil Arrestor Disconnects |
± 1.67 |
14.99 |
16.66 |
18.33 |
x |
- |
| 71.2.7 |
Breaker Handle |
± 2.50 |
22.50 |
25.00 |
27.50 |
x |
x |
| 71.2.9 |
Ground Bar |
± 2.50 |
22.50 |
25.00 |
27.50 |
x |
- |
| 71.2.9 |
Oil Level Gauge |
± 3.00 |
27.00 |
30.00 |
33.00 |
x |
- |
| 71.2.3 |
EL Bayonet |
± 6.00 |
54.00 |
60.00 |
66.00 |
x |
- |
| 71.2.6 |
Load Break Switch |
± 6.00 |
54.00 |
60.00 |
66.00 |
x |
- |
| 8.8 |
Indicator Light (Signal) |
± 0.50 |
4.50 |
5.00 |
5.50 |
- |
x |
| 8.7 |
Stud .375" (3/8") |
± 1.50 |
13.50 |
15.00 |
16.50 |
- |
x |
| 8.6 |
LV Bushing Polymer 1.375" |
± 1.65 |
14.85 |
16.50 |
18.15 |
- |
x |
| 8.6 |
LV Bushing Porcelain 1.375" |
± 2.29 |
20.61 |
22.90 |
25.19 |
- |
x |
| 8.7 |
Stud .500" (1/2") |
± 2.50 |
22.50 |
25.00 |
27.50 |
- |
x |
| 8.7 |
Stud .675" (5/8") |
± 2.50 |
22.50 |
25.00 |
27.50 |
- |
x |
| 8.6 |
LV Bushing Polymer 1.83" |
± 3.00 |
27.00 |
30.00 |
33.00 |
- |
x |
| 8.7 |
Stud .750" (3/4") |
± 6.00 |
54.00 |
60.00 |
66.00 |
- |
x |
| 8.7 |
Stud 1.00" (1") |
± 6.00 |
54.00 |
60.00 |
66.00 |
- |
x |
| 8.7 |
Stud 1.25" (1 1/4") |
± 6.00 |
54.00 |
60.00 |
66.00 |
- |
x |
| 8.6 |
LV Bushing Polymer 2.75" |
± 6.25 |
56.25 |
62.50 |
68.75 |
- |
x |
| 8.6 |
LV Bushing Porcelain 2.75" |
± 6.67 |
60.03 |
66.70 |
73.37 |
- |
x |
| 8.12 |
Side Mount HV Bushing |
± 6.67 |
60.03 |
66.70 |
73.37 |
- |
x |
| 8.12 |
HV Porcelain Bushing |
± 8.00 |
72.00 |
80.00 |
88.00 |
- |
x |
Conclusion
Maddox transformers are assembled and tested in accordance with the highest standards of quality. Call us today to receive a custom quote on a new or reconditioned transformer, or to request repair or field service on your current transformer!
