Selector switches are used to control ON or OFF of electrical circuits by changing the contacts and are available in below types:
- Toggle switch: control by handle (knob) and changing the contacts.
- Rotary switch: control by rotating and changing the contacts.
- A) 3 way (position state)
- B) 4 way (position state)
Note1: For rotary switch direction is not important. It can rotate clockwise or counter clockwise.
We use different types of selector switches in electrical panel:
- SPST: Single Pole Single Throw (2 Terminals, Toggle switch)
2- SPDT: Single Pole Double Throw (3 Terminals)
3- DPST: Double Poles Single Throw (4 Terminals)
4- DPDT: Double Poles Double Throw (6 Terminals)
Note2:
Pole: Number of circuits (wires).
Throw: Number of positions (connection).
So for electrical panel normally we need below switches:
- Toggle switch: Basic ON/OFF switch, ON/Bypass, Manual/Auto
- Ampere-meter selector switch (Ammeter selector switch): To reduce the number of Ampere meters (Ammeters) and save money. It select the line which we want to read the ampere value at each time.
- Volt-meter selector switch: same as Ammeter for volt measurement.
Leave a Reply