Keylock Switches
Copyright ©2015
All Rights Reserved.

Keylock switches are activated by a key that is turned in a circle and can stop in a range of positions. Important physical specifications to consider when searching for keylock switches are the angle between positions and the mechanical life.  The angular distance (in degrees) between positions is important to consider. For example, for a 4-position switch, the angle of throw is 90 degrees, for a 100-position switch, the angle of throw is 3.6 degrees.  The mechanical life is the maximum life expectancy of the switch. Often, electrical life expectancy is less than mechanical life, please consult manufacturer.

Important electrical specifications to consider when searching for keylock switches include maximum current rating, maximum AC voltage rating and maximum DC voltage rating.  Keylock switches can be constructed as a single deck or multi-deck.  Pole specifications are related to the construction.  A single deck will have specifications for number of poles; a multi-deck will have specifications for number of decks and number of poles per deck.  The number of poles is the number of separate circuits that can be activated through a switch at any given time.  The number of decks is the maximum number of decks that can be attached to a common actuating shaft.  The poles per deck is the number of separate circuits that can be activated through a switch at any given time per deck.  Materials of construction for the base or housing and key or switch knob material of keylock switches includes metal and plastic.

Stop styles for keylock switches can be fixed, adjustable, or continuous. Fixed stop positions come fixed from manufacturer. The end user can change adjustable stop positions.  Continuous style switches have no stops.  Contact styles for keylock switches are shorting or non-shorting.  Shorting switches are Make Before Break; this is useful in preventing arcing during position change since the next position is connected before the previous position is disconnected.  Non-shorting switches are Break Before Make; the switch opens the preceding circuit before closing the next.

Terminal choices for keylock switches include wire leads, solder terminals, screw terminals and PCB pins. Common features include optional coded outputs, momentary on, wiping contacts, CE certification, CSA certification, UL listed, dustproof, and weather resistant or waterproof.  A switch with optional coded outputs can be configured to provide coded output, such as BCD or Octal.  Momentary on is a feature in which the switch maintains its position for only as long as it is positively loaded or actuated; returns to unloaded position when it is let go (for example, an ignition switch). Wiping contacts provide self-cleaning and usually low resistance. Wiping action creates mechanical wear.  An important environmental parameter to consider when specifying keylock switches is the operating temperature.
|   HOME    |
Go back to Process Automation and Control Tutorial
- Switches
- Emergency Stop Switches
- Keylock Switches
- Pushbutton Switches
- Thermostats and Thermal Switches
- DIP Switches
Electrical Equipment
Free Magazines and more ...