Transformer Cover Plate Bolt Torque

What should be tightening torque for the cover plate bolt for 50 kVA sealed type transformer? The cork packing thickness is 6 mm and bolt type is 10Mx40mm. Spacing between two bolts is 50 mm. Flanger opening is 940x396 mm. Width of flanger is 50mm. Strength class of the bolts is 4.8.


In addition to the normal torque considerations for bolts, you also need to consider the gasket installation.

I’ve seen bolts torqued to THE standard specification and the pressure squeezed the gasket completely out of position. Please refer to your transformer manufacturer’s instruction.

Absent that information, you want a torque value that gives good gasket compression and security.

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