What are the internal resistance and voltage rating of a 450
     What are the internal resistance and voltage rating of a 450 W automatic washer that draws 3.75 A from electrical supply? 
  
  Solution
Automatic washer is single phase system.
Given current drawn is I = 3.75 A
Power absorbed is P = V*I
Voltage V = P/I = 450/3.75 = 120 V
Internal resistance R = V/I = 120/3.75 = 32 ohm.

