Transformers & Fittings

The transformer is fitted with an off-circuit tap changing switch to obtain required tap voltage. It can be hand operated by a switch handle mounted on the tank. Locking device is fitted to the handle to padlock it on any tap position and also to prevent any unauthorized operation of switch. The switch mechanism is such that it can be locked only when it is bridging two contacts on any particulars tapping position and cannot be locked in any intermediate position.
It is important that the transformer should be isolated from the live lines, before moving the switch. Operating the switch when transformer is energized, will damage the switch contacts due to severe arcing between the contacts, and may damage windings also.

Contact bridging links are provided inside the transformer tank to obtain required tap voltage. Links are required to be unbolted and are fixed in any required position of the tap. For transformer furnished with thermometers for both oil and winding temperature, the signaling contacts recommended to be set to operate at the following temperatures.

	Alarm	Trip
Oil Temperature	85 deg. C +/-2 deg.c	95 deg. C +/-2 deg.c
Winding Temp	100deg. C +/-2 deg.c	110deg. C +/-2deg.c

• CT secondary terminals must be shorted and earthed if not in use.
• Check relief vent diaphragm for breakage. See that the bakelite diaphragm at bottom and glass diaphragm at top are not ruptured.
• Check all the gasket joints to ensure that there is no leakage of transformer oil at any point.
• Clear off extraneous material like tools earthing rods, pieces of clothes, wastes, etc.
• Lock the rollers for accidental movement on rails.
• Touching of paint may be done after erection.

• Two Earthing Terminals
• Lifting Lugs
• Drain - Cum Filter Valve
• Pressure Relief Device
• Silicagel Dehydrating Breather
• Oil Level Indicator
• Thermometer Pocket
• Conservator With Drain Plug And Filling Hole
• Air Release Plug
• Jacking Lugs (Above 1600 KVA)
• Filter Valve (Top Tank)
• Under Base Unidirectional Flat Rollers