A transformer supplying a motor control centre is observed to be running significantly hotter than expected, even though the connected motors are not fully loaded. An electrician uses a power quality meter and finds a very low power factor. What is a direct consequence of this low power factor contributing to the transformer's overheating?

Question: A transformer supplying a motor control centre is observed to be running significantly hotter than expected, even though the connected motors are not fully loaded. An electrician uses a power quality meter and finds a very low power factor. What is a direct consequence of this low power factor contributing to the transformer's overheating?

Answer options:

• The transformer's core is saturated.
• Increased magnetizing current.
• The transformer is operating at reduced kVA. ✅ Higher apparent power, leading to increased copper losses (I²R losses) in the windings.

Correct answer: Higher apparent power, leading to increased copper losses (I²R losses) in the windings.

Explanation: A low power factor means that the system is drawing more apparent power (kVA) for the same amount of real power (kW). This translates to higher current flow through the transformer windings than necessary for the useful work being done, leading to increased copper losses (I²R losses) and consequently, higher operating temperatures and potential overheating.