Home » English riddles » Transformer » Transformer Riddle No. 24 – Essentiality Tertiary winding in Power Transformer » Reply To: Transformer Riddle No. 24 – Essentiality Tertiary winding in Power Transformer Reply To: Transformer Riddle No. 24 – Essentiality Tertiary winding in Power Transformer 2021-08-03 at 11:08 am #1637 R K Mohapatra The system is in operation and the switching is infrequent .