10 Why is a generator armature harder to rotate when it is connected to and

# 10 why is a generator armature harder to rotate when

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10) Why is a generator armature harder to rotate when it is connected to and supplying electric current to a circuit? When the generator is not connected to any load you only have to overcome the friction of the armature mechanism. Once a load is connected, you now not only have to overcome the friction but must also supply the work needed to drive the current in the circuit. 11) An induction coil in an automobile is much like an AC transformer that boosts low voltage to high. The 12 V from the battery is DC, so a device interrupts the current on and off, producing a changing current equivalent to AC. Find the ratio of primary to secondary turns to boost 12 V to the 24,000 V required for the sparks plugs to “fire”. 12) A certain types of earthquake detector consist of a little box that contains a massive magnet suspended by sensitive springs. The magnet is surrounded by stationary coils of wire that are fastened to the box, which is firmly anchored to the earth. Explain how this device works, using two important principles of physics learned in this class. The suspended massive magnet, with its large inertia, will tend to remain stationary during an earthquake. The stationary coils of wires are anchored to the earth and will move with the earth’s crust during an earthquake. The relative motion of the coils and the magnet will cause a change in flux through the coils that will induce a voltage in the coils.
• Spring '17
• Roger Kwok
• Magnetic Field

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