By MyPros Staff

The majority of washing machines in America are top-loading, and the major difference between them and front-loading units is that the tubs, motor and other components have been repositioned. We will therefore describe the top-loading units, which will still give you owners of front-loading machines a good introduction to how they work.

The vast majority of inner tubs will have hundreds of holes that let the water reach the outer tub, where it is held until pumped out later. A large, finned agitator sits in the middle of the inner tub, and its shape plus the force of the motor turning it moves the clothes up, down, back and forth in the water.

A powerful electric motor moves the agitator in the wash cycle then spins the inner tub itself to get the water out of the clothes by centrifugal force, sending it through the holes to the outer, stationary tub. At this point, during the “spin” cycle, another electric motor will kick in to pump the water from the outer tub and send it down the drain.

Valves, timers and switches

The fill valve ("water inlet valve") manages the delivery of hot and cold water to the washer. But running the whole show is a timer switch, normally the largest dial on the control panel. Historically it has been a mechanical device similar to simple clock, but new machines that have gone completely electronic may present you with a digital control and readout instead of a dial.

There may or may not be a separate “Start” switch, as it is often a part of the timer dial assembly. After turning the dial to the proper point for selection of a “wash type” (normal, permanent press, etc.), you normally pull or push the knob to start the machine.

Naturally, these switches and dials vary from model to model, just like the other common switches or knobs on the control panels. There may be additional switches, of one or more kinds, to control and adjust spin speed, water temperature, special fabric settings and the like.

The power parts

Since electric motors can reach full speed almost instantaneously, most washing machines will have some sort of “clutch” to dampen the start-up effects. Some units use a simple method where the drive belt slips momentarily on a pulley then tightens gradually. On others, the clutch is car-like, with a standard drum-and-pad construction and operation.

Some few washing machines connect the motor directly to a transmission, forgoing the belt system. Still, most washers use rubber belts to transfer the motor energy to the transmission (and sometimes the pump). Once again, like a car, the belt is a black, rubber loop of some two to three feet in length.

The belt, although far from being “high tech,” is a most admirable "fail safe" mechanism for a washing machine. If the tub, agitator or motor were to get stuck or “freeze up,” the belt would most likely slip, stretch or break, thus saving the motor and transmission from costly damage.