Placement - online test I (transformers)

Front

Which part of a transformer is responsible for reducing hysteresis loss? Options: a) Copper windings, b) Laminated core, c) Oil cooling system, d) Breather

Back

Laminated core

Answer explanation

(b) Laminated core → Laminations reduce hysteresis and eddy current losses, improving efficiency.

Front

What happens if the secondary winding of a transformer is open-circuited?

Back

No power is transferred to the secondary

Answer explanation

(c) No power is transferred to the secondary → With an open secondary, no current flows, and power transfer stops.

Front

Why is the tertiary winding used in a three-winding transformer?

Back

To stabilize unbalanced loads

Answer explanation

(c) To stabilize unbalanced loads → The tertiary winding helps in load balancing and voltage stabilization in three-phase transformers.

Front

Which material is commonly used for transformer core to reduce losses? Options: a) Copper, b) Aluminum, c) Cast iron, d) Silicon steel

Back

Silicon steel

Answer explanation

(d) Silicon steel → Silicon steel has low hysteresis loss and high permeability, making it ideal for transformer cores.

Front

Why is a Buchholz relay used in transformers? Options: a) To measure voltage regulation, b) To protect against internal faults, c) To improve insulation, d) To step up voltage

Back

To protect against internal faults

Answer explanation

(b) To protect against internal faults → The Buchholz relay detects gas formation due to internal faults and prevents transformer damage.