Final answer:
The starting current of an induction motor increases momentarily when the circuit is energized due to an absence of back emf. Once the motor reaches speed and generates back emf, the current decreases to normal levels. The principles of Lenz's Law dictate the direction of induced currents in interacting coils.
Step-by-step explanation:
When the circuit of an induction motor is energized, the starting current, also known as inrush current, typically increases momentarily. This happens because when the motor starts from a standstill, there is no counter electromotive force (emf) to oppose the applied voltage. The inductor in the motor - which the rotor effectively is when not turning - initially behaves like a short circuit, allowing a large current to flow. As the rotor begins to spin and generate back emf, the current gradually reduces to its normal running level. This high starting current can potentially cause damage due to excessive heat if not properly controlled.
In scenarios where coil interactions are being analyzed, like the ones involving Lenz's Law, the direction of the induced current is such that it opposes the change that produced it. For instance, if the current in coil 1 increases, the induced current in coil 2 will flow in a direction to create a magnetic field that opposes the increase. Likewise, if the current in coil 1 decreases, the induced current in coil 2 will attempt to maintain the magnetic field by flowing in a direction that strengthens it. If the current in coil 1 is steady, there will be no change in the magnetic field, and thus no induced current.