A voltage commutated chopper feeds power to an electric car (batterypowered). The battery voltage is 60 V. Starting current is 60 A and the SCR turnoff time is 20 μs. Calculate the value of inductance (L) required for the commutating circuit.

To calculate the required inductance (L) for the commutating circuit, we can use the following formula related to SCR (Silicon Controlled Rectifier) turn-off and the necessary inductance for proper commutation:

[ L = frac{V cdot t}{I} ]

Where:

– ( V ) = Battery voltage (60 V)

– ( t ) = SCR turn-off time (20 μs = 20 x 10^{-6} s)

– ( I ) = Starting current (60 A)

Now substituting the values into the formula:

[ L = frac{60 text{ V} cdot 20 times 10^{-6} text{ s}}{60 text{ A}} ]

[ L = frac{60 cdot 20 times 10^{-6}}{60} ]

[ L = 20 times 10^{-6} text{ H} ]

[ L = 20 mu H ]

So, the value of inductance ( L ) required for the commutating circuit is 20 μH.