## a) Current in an AC Induction Motor Under Different Load Conditions The current drawn by an AC induction motor depends on the load applied to its shaft: - **No-load Condition:** - The motor draws a small current called "no-load current" (typically 30-40% of full-load current). - This current supplies iron losses, friction, windage, and a small amount of load. - The slip is minimal, so the rotor and stator fields are nearly synchronous. - **Increasing Load:** - As mechanical load increases, the rotor slows down slightly (slip increases). - Increased slip induces a higher rotor current, which increases the torque. - To provide this extra torque, the stator draws more current from the supply. - **Full-load Condition:** - The current drawn is at or near the motor's rated (full-load) value. - Both stator and rotor currents are significant, supporting mechanical output and losses. - **Overload Condition:** - If the load exceeds rated capacity, motor current increases beyond rated value. - Excessive current can cause overheating and potential damage if sustained. --- ## b) Diagram: Current vs. Load in an Induction Motor Below is a simplified diagram showing how stator current varies with load: ``` Stator Current (I) ^ | / | / | / | / |_______/________________> Load (Torque) | No Load ``` - The curve starts at a minimum value (no-load current) and rises as the load (torque) increases. - The slope shows increasing current with increasing load. --- **Note:** For a more precise diagram, refer to typical induction motor performance curves found in textbooks.