Question

Draw a labelled diagram of an Electric Mixer.

Hint:

If your mixer suddenly stops running during heavy grinding, do not panic. The bimetallic Overload Protector (OLP) switch at the bottom has likely tripped to protect the motor. Unload the jar, wait 2 minutes for the bimetallic strip to cool, press the red reset button, and resume operation.

Answer 1

Step 1: Overview of Electric Mixer Construction:
An electric kitchen mixer-grinder is an electromechanical appliance designed to grind and blend food ingredients. It relies on a high-speed AC universal series motor to spin sharp stainless steel blades within a jar.

Step 2: Component-by-Component Description of the Diagram:
Since drawing the diagram directly is not required, below is a complete, detailed architectural breakdown of the components, their placement, and how they connect:

• The Outer Insulated Body (ABS Plastic Shell):
  • Form of the shell: A heavy, bell-shaped outer housing made of high-strength, impact-resistant ABS plastic.
  • Purpose: Provides structural support, dampens motor vibrations, and insulates the user from electrical parts.
• The Universal Motor (Located at the Core Base):
  • Position: Mounted vertically inside the lower half of the plastic shell.
  • Key Components to Label:
    • Stator Field Coils: Thick copper coils wound around a laminated iron core, generating the excitation field.
    • Rotor (Armature): The central rotating shaft wound with wire coils.
    • Commutator and Carbon Brushes: Spring-loaded carbon blocks that transfer current to the rotating commutator bars.
• The Cooling Fan (At the Base of the Motor Shaft):
  • Position: Mounted at the bottom end of the vertical motor shaft.
  • Ventilation: Positioned directly above air intake slots in the bottom base cover. It draws cool air in and forces hot air out through side vents to prevent the motor from overheating.
• The Overload Protector (OLP) Switch (Bottom Base):
  • Position: Mounted in the bottom base cover next to the power cord entrance.
  • Purpose: A bimetallic circuit breaker that trips the power if the motor stalls or is overloaded, protecting it from burning out. It features a red reset button on the outside.
• The Speed Controller Rotary Selector Switch (Front Panel):
  • Position: Mounted on the front face of the plastic shell.
  • Wiring: Connected to multiple taps on the field windings. Turning the knob changes the active turns in the field coils, adjusting speed through three levels (Low, Medium, High).
• The Coupler (Top Spindle Interface):
  • Position: Mounted on the top of the motor shaft, projecting through the top of the plastic body.
  • Material: Made of durable hard rubber or tough nylon. It has interlocking teeth that connect directly with the jar's blade assembly.
• The Grinding Jar (Top Assembly):
  • Position: Detachable jar that locks onto the top of the mixer base.
  • Key Components to Label:
    • Stainless Steel Jar Body: Holds the ingredients.
    • Blades: Sharp, multi-pronged stainless steel blades mounted on an internal spindle.
    • Jar Coupler: Located on the underside of the jar, locking with the motor coupler.
    • Lid and Rubber Gasket: Seals the top of the jar to prevent leaks.