JSS 2 THIRD TERM BASIC TECH Week 2
Topic: PRINCIPLE OF OPERATION OF ELECTRIC FAN AND GRINDER
(a) The Electric Fan
The electric fan is basically an induction motor of the squirrel – cage rotor type in most cases. The shaft of the motor at the fan blade end is provided with a flat side onto which the fan blade is tightly fitted to and secured with a screw or a left hand thread cap to prevent the fan blade form becoming loose and sliding off during motion.
(b) The Grinder
Any machine which employs electric motor as its ‘prime movers’ turning force in order to produce granulated, paste or powdered form from solid substances e.g. maize, sorghum, soybeans, groundnuts, dried beans, etc. Grinder in many case perform the function of blending e.g. liquidizing of soft fruits and plants products e.g. fruits, tomatoes, soft pepper, onions, etc. Grinding stones are usually limited to benches and hand tools for metal surface. Below is the construction and operation of a regular grinder for foodstuffs only.
Grinding Shaft
The figure shows the complete assembly of grinder with is prime mover i.e. the electric motor coupled with a set of pulley and belt.
The grinding shaft image above shows the actual grinder, which is a small cross sectional rod, welded to a larger shaft carefully chosen to turn in the grinder with no space for wastage of items being grinded.
