Push Buttons, Switches & Signaling Devices
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Push buttons are mechanical switches that open or close one or more circuits to control an aspect of a machine or process. Push button switches are typically used to start or stop a process, with the switch being in a normally-opened or a normally-closed position. An indication light can be included in the push button to show the state of the switch.
Indication and signaling are devices that give an audible or visual indication of the status of a situation that needs attention. Examples include: beacons, buzzers, pilot lights, signal towers, sounder horns and strobes.
Selector switches are mechanical switches that open or close electrical contacts by rotating the handle right, left or center. These switches normally come in 2-position or 3-position options and with or without keys.
Foot switches or foot pedals are devices that are used to open or close an electrical circuit by pressing a pedal with a user’s foot, making them ideal for a hands-free operation.
Subcategories
More Information about Switches, Push Buttons & Signaling Devices
Control stations provide rugged, industrial casings for push buttons, pilot lights and joysticks. Some control stations are designed to prevent accidental operation with locking mechanisms or twisting motion functions.
Potentiometers are variable resistor devices that adjust voltage manually through electronic or mechanical control of its resistance as electric current moves through it. This allows the potentiometer to accurately measure voltage and achieve variable voltage from a fixed voltage source.
Biometric switches are devices that use fingerprint-recognition technology to allow access to authorized personnel to restricted zones and sensitive equipment functions without the worry of lost keys or stolen passwords.
Joysticks are switches that use inductive, photoelectric or potentiometric sensing systems to transmit joystick movement into an output signal. The joystick switch contact mechanism is actuated depending on the direction the lever is pushed and sometimes by how far it is pushed.
Maintaining NEMA 4 Rating When Making Enclosure Penetrations
Cutouts are very common when modifying enclosures for push buttons, indication lights, conduit entries or mounting hardware. Cutting into an enclosure runs the risk of eliminating the protective nature of the NEMA rated attributes. Proper steps must be followed in order to preserve the NEMA rating of an enclosure.
Devices mounted to the enclosure must have the same NEMA rating as the enclosure.
This means that if the devices are installed to the manufacturer's specifications, they will be able to maintain the NEMA rating of the enclosure.
Water tight conduit hubs must be used when running wire through a cutout in an enclosure.
There are many different types of conduit hubs that are used to secure conduit to an enclosure. However, only certain conduit hubs are rated for a watertight seal. By using water tight hubs, the NEMA rating of the enclosure is maintained.
Bonded washers are necessary when mounting hardware to an enclosure.
If standard mounting hardware is used, the NEMA rating of the enclosure will no longer be maintained. Bonded washers have rubber gaskets that make a watertight seal around the drilled hole. It is also important to make sure the material used for the bonded washer matches the material of the enclosure. Stainless steel enclosures require stainless steel bonded washers.