Selector Switch

Selector switches are available in a variety of styles including illuminated, non-illuminated, and non-illuminated key operated. Styles offered range from maintained or spring return, incandescent or LED, and 3–50 amps. Work with a selector switch specialist to determine the best product for your application.

This overview focuses mainly on the construction and functionality of non-illuminated selector switches. The non-illuminated selector switch is represented in both the selector switch diagram as well as the selector switch video overview.

What is a Selector Switch?

A selector switch works on a simple principle:

• It contains a selector mechanism on the front of the panel.
• Inside the enclosure, it connects to a wide range of potential contact combinations via contact blocks.

• A pushbutton uses a plate to press down both contact plungers at the same time.
• A selector switch uses a rotating cam with ridges and flats, allowing plungers to be actuated independently.

Selector switches are available in 2, 3, or 4-position versions and are often used when multiple control options are required. In general:

• The center position is the starting cam position.
• Turning left presses the left plunger.
• Turning right presses the right plunger.

How Selector Switches Work

Selector switches use cams in combination with contact blocks to provide a wide range of circuit openings and closings.

• In diagrams, “X” designates a closed circuit (energized or “on”).
• “O” designates an open circuit (not energized or “off”).

For example, in a pump application, a 3-position selector switch can open or close two circuits: “hand” and “auto”. The left, center, and right positions determine how each circuit is activated.

Indicating lights are often included as part of selector switches:

• Setting the selector switch tells machines how to operate.
• Indicating lights tell us whether the machine is operating or failing to operate.

Selector switches are especially useful where maintained contact is needed (e.g., Hand–Off–Auto applications).

Contact Blocks

Contact blocks are an integral part of selector switches. They can have:

• Normally Open (NO) contacts
• Normally Closed (NC) contacts

Single circuits contain one NO or NC contact. This is a cost-effective option when only one contact is needed.

Dual circuits contain two contacts in one block. Common combinations include:

• 1 NO + 1 NC
• 2 NO
• 2 NC
• Special versions with delayed opening or early closing

Dual circuit blocks save space inside enclosures and add twice the functionality, since one switch can operate two circuits.

Multiple contact blocks can also be stacked for more complex applications. For example, you can mount 4 dual-circuit blocks to a 30mm pushbutton, giving a total of 8 circuits.

Selector Switch Video Overview