APPLIANCE CONTROLS Appliance controls, as the name implies, regulate the use of electrical appliances used everyday. They allow us to turn appliances on and off. There are two general classes of controls: manual and automatic.

MANUAL CONTROLS Manual controls turn the appliance on and off, and some types set the appliance at a desired temperature by unit and, by toggle action, closes the contacts to the lower unit. The lower unit comes on and remains on until its preset temperature is reached and the thermostat is satisfied.

controlling the current flow to the unit. The automatic control, in addition to turning the unit on and off, maintains an even heat in the unit; for example, the automatic controls on kitchen appliances result in better

Figure 7-8.- In-line toggle switch. food preparation and allow more time for the food preparer to accomplish other tasks. Manual controls turn the heating unit on and off by making or breaking the electrical circuit. Manual controls consist of the toggle switch and different types of rotary switches.

Toggle Switches Toggle switches are used to make and break the electrical circuit on many small appliances. Figure 7-8 shows one type of toggle switch that is installed in an appliance cord. This type of switch cannot be repaired. You must replace it. Figure 7-9 shows a typical wall-mounted toggle switch used to control appliances. New switches are usually so inexpensive that repairing an old one is not economical. 

Rotary Switches Rotary switches have fast make-and-break action and usually have three or more heat settings. The spring

Figure 7-9.- Typical wall-mounted toggle switch.

Figure 7-10.- Typical rotary switch. action contained in this type of switch enables it to operate extremely fast and eliminates the usual pitting and burning of its contacts. Rotary switches are normally used to control the top elements of an electric range. Changing the position of

the switch changes the connection to the element and varies the voltage; for example, the LOW position connects the elements in series to a 120-volt Rower source, and the HIGH position connects the elements in parallel to a 240-volt power source. Various combinations of these connections deliver different heat from the unit, all controlled by the rotary switch. Figure 7-10 shows a typical rotary switch.

Repair of this switch is recommended only as a temporary measure. Repair consists of cleaning and adjusting contacts, replacing worn and inoperative parts, and lubricating the contacts and switch mechanism with nonoxide grease for smoother operation. The switch should be replaced as soon as a replacement is available. The pull-to-turn switch, as shown in figure 7-11, is constructed to carry the higher loads connected with

Figure 7-11.- Pull-to-turn switch.

commercial ranges and oven installations in galleys. The current is interrupted ahead of the make-and-break action of the switch contacts. That eliminates the usual pitting and burning of contacts. This switch cannot be repaired; you must replace it.