A device is rated to operate at a voltage of 24V. It has a protection circuit consisting of (4) 25 A fuses.
a) Discuss whether these fuses are connected in series or parallel?
b) What is the maximum power of the device?
c) If this device was redesigned to operate at 12V, while still providing the same power, quantitatively assess the new demands of the circuit.
a. If they are connected in parallel,
the current capability will be 100Amps.
There is no advantage of connecting them in series, because you will still have a 25Amp circuit. It only incrases
the cost. If the operating current of the device is 25A, four 25A fuses in
parallel won't give much protection.
b. P = VI. VI = The rated Voltage and current.
P = 24 * 25 = 600W.
c. 12I = 600,
I = 50A.
We need to multiply the current rating
of our fuses by 2.