A transformer on no-load is switched on to a source of voltage. It will draw a current ---
- A. which is the same as the steady-state magnetizing current
- B. which is several times the steady-state magnetizing current, depending upon the initial state of the residual flux in the transformer core.
- C. which is several times the steady-state magnetizing current, independent of the initial state of the residual flux in the transformer core.
- D. which is twice the steady-state magnetizing current provided the core has no residual flux.
Answer: B. which is several times the steady-state magnetizing current, depending upon the initial state of the residual flux in the transformer core.
Explanation: Switching-on inrush is several times the magnetising current and depends on the residual flux and the switching instant.