Question

Consider an electromagnet (e.g. in a relay) that is operated at 50 A. If the inductance of the coil is 100 H and the time to switch-off the current is 1 ms, what voltage will be developed across its terminals?

Answer 1

5 x 10⁶ volts

Step-by-step explanation:

`i_(o)` = Initial value of current = 50 A

`i_(f)` = Final value of current = 0 A

Δt = time taken = 1 ms = 0.001 s

`V` = Voltage developed across the terminals

Voltage developed across the terminals is given as

`V = (L(i_(f) - i_(o)))/(\Delta t)`

`V = -((100)(0 - 50))/(0.001)`

`V` = 5 x 10⁶ volts