Cam Switch: Function, Types, Benefits, Diagrams – All you need!

Do you know what a cam switch is? It is a well-known device in the energy market since the 1900s. Since it is first invented, most electrical professionals have used this device in their electrical projects. If you are not familiar with this unique device, keep on reading to understand the main types, applications, advantages, and disadvantages of the cam switch.

What is a cam switch?

A cam switch is used to perform make and break operations in a sequential way by rotating the switch to different positions. The cam, which closes and opens the contacts, has rotary movement to multiple positions, thereby multiple circuit functions can be controlled.

A cam switch provides the transmission of electrical energy from one point to another by rotating at various angles with the help of a handle and shaft. Its contacts change position by turning the handle.

Types of cam switches

Cam switches have various types. Some of them are listed below:

Isolator switches

Isolator switches are ON-OFF switches that are used to isolate the power to a particular area of operation.

Applications: Switching of main/control and instrumentation circuits motor ON-OFF and other special application circuits.

Changeover switches

Changeover switches are used to operate two different circuits with a different number of inputs and outputs.

Applications: Power supply to generator changeover, Auto/Manual changeover, Standby/Remote changeover, and other special application circuits. Mainly used in distribution panels, UPS, etc…

Multistep switches

Multi-Step switches connect different circuits to a common supply or vice-versa.

Applications: As tap changing switch for Transformer/Stabiliser and other special application circuits.

Voltmeter selector switches

Voltmeter switches measure voltages between phases and phase and neutral.

Ammeter selector switches

Ammeter switches measure currents in different circuits with a current transformer a single analog ammeter and a switch.

Motor control switches

Motor control switches are typically used for “Forward-Reverse”, “Star-Delta” and “Two Speed Forward-Reverse”.

They are also designed to operate with a contactor having a built-in tripping feature in the event of power failure and overload.

Gang switches

Gang switches increase the capacity of circuits by ganging in serial or parallel operations for different circuit capacities. Serialising enhances the power of the battery supply and paralleling the power of the resistor.

Applications: In railway coaches for controlling the alternator and battery supply. Also in telecom panels and special application circuits.

Control switches

Control switches are used to energize contactors for controlling motor operations. Most of the switches are “Spring return” types for latching the circuit with NO contact and facilitating tripping by the tripping device.

Applications: Control switches offer a unique alternative to multiple “Push Button Stations” when one switch controls instead of many push buttons. A control switch with many positions is offered for a suitable combination.

Advantages of cam switch

Cam switch has some benefits. Some of them are listed below:

• It is very simple to use.
• It works like a transfer switch and transfers energy from one point to another.
• It is cheap and compact in size.
• It requires no maintenance.
• It can be used in AC and DC applications.
• It has a high degree of IP protection.
• It can be mounted to the panel door or inside the enclosure.
• It has lots of contact variations.
• It can operate in low and high temperatures without derating.
• It has a short installation time.
• It has a long electrical and mechanical life.

Disadvantages of cam switch

Cam switch has some drawbacks. Some of them are listed below:

• It does not have any protection function against thermal and magnetic currents.
• It cannot be controlled remotely.
• A physical rotational force must be applied to switch it.
• It cannot switch very high currents.

Cam switch applications

Cam switches have a wide range of application areas. Some of them are:

• Oil and gas.
• Food & beverage.
• Panel builders and electrical enclosure.
• Machine tools & wood industry.
• Packaging.
• Kneading-trough.
• Vegetable cutting machine.

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How to read contact diagrams of cam switches?

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Wiring diagrams of cam switches

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