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    How to select a limit switch

    Looking to select a limit switch? Take a look at Eaton's.
    Eaton's limit switches

Why choose a limit switch for a sensing application

Take a look at some key indicators that a limit switch might be appropriate for your application.

 

Variables that should influence which limit switch to select

Considerations include aspects as simple as size through more complex options like sensor output requirements. Review how to select a limit switch.

 

Speciality limit switches

Sometimes an application requires a limit switch to proceed in a unique way. Take a look at speciality limit switches and their means of operating.

E50 NEMA heavy-duty plug-in limit switch

E50 modular plug-in limit switches are the industry standard with versatility of design and high reliability for low maintenance, installation and inventory costs.

 

Why would you choose a limit switch for a sensing application?   

  • Very robust and survivable
  • Switch setpoints are precise, accurate, and repeatable
  • Consume little or no power
  • Can switch loads with high inductance
  • Can operate in environments with high levels of electromagnetic noise
  • Simple to apply


glass bottles on a conveyor

E49 mini metal limit switch

E49 mini metal limit switches are the ideal switches for those who need a cost-effective, compact solution, but do not want to sacrifice durability. The small size, metal body and long mechanical life make the E49 mini metal the perfect switch for machinery OEM applications.  


Variables to consider when selecting a limit switch

Take into consideration the following variable when selecting a limit switch.

Phisycal size

Select a switch family that physically fits in the application location

Target specifics

Select an actuator type and orientation appropriate for your particular target type, shape, material, and surface finish

Voltage rating

Review current switching ratings for the voltage level of your system

Rate of actuation

Evaluate the rate of actuation and expected machine lifetime versus mechanical and electrical lifetime ratings for the switch

Contact switches

Select the appropriate contact configuration for the application 

  • Normally Open contact switches to close (or "make") the circuit when actuated
  • Normally Closed switch opens and breaks the circuit when actuated
  • Many switches have both Normally Open and Normally Closed contacts
  • Some switches have multiple Normally Open and Normally Closed contacts for switching multiple electrical circuits with the same switch

Wiring and connection

Review wiring and connection requirements and select a switch body with the appropriate interface

 

Important speciality limit switch types and features

Neutral position switch

Neutral position switches 

Switches that operate and actuate in both clockwise and counterclockwise directions.  When the switch operator moves clockwise to the Operate Point, one set of contacts close.  If the switch operator moves counterclockwise the same number of degrees to the alternate Operate Point, the other set of contacts close.  With this type of limit switch, direction of operation of a machine can be detected

Two-step switch

Two-step switches 

Specialty switches, rotating the switch operator 10 degrees actuates one set of contacts, and moving the lever operator to 20 degrees (in same direction) actuates the second set of contacts. With this switch, physical attributes of the object (height, orientation, position, completeness of assembly) can be determined and subsequent segregation or control automatically provided by a single limit switch.

Gravity return switch

Gravity return switches

Switches that have no spring return mechanism - the weight of the operating lever provides the force to return the actuator to its free position.  Gravity return switches are usually mounted with the operating head upside down.

Precision switches 

Specialty switches that actuate with high precision and typically very low actuation force.

Factory sealed switches 

Pre-assembled at the factory and is epoxy-filled in order to provide the highest possible level of sealing for the most extreme application environments.

Indicating lights

Switches with built-in indicating lights that provide information on switch status

Hazardous Location switches 

Switches designed to contain any transient explosion within the switch itself and thereby operate in areas that require explosion-proof ratings

Safety switches 

Switches designed for use in machine guarding and other human safety applications.

E47 precision limit switches

Eaton's E47 precision switches provide high-accuracy switching at an affordable price. A variety of standard features, such as current capacity, operating force, travel characteristics and actuators, lets you custom fit the switch to your application.

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