Download Rotary Switch Basics - Electroswitch Electronic Products

Rotary Switch Basics
“Using Rotary Switches in Your Design”
Electroswitch Rotary Switches
Electroswitch offers many varieties of rotary switches for different application
requirements. Electroswitch has acquired rotary switch lines from Stackpole,
Shallcross, ASM, CRL / Centralab and Oak Grigsby.
Rotary Switch Design Considerations &
Common Specifications
• How many poles?
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Open or enclosed Frame switch?
Changing Torque or Actuation Feel?
Contact Material Advantages?
Sealing Requirements?
Size requirements or limitations?
How many positions?
Mounting Style –
PCB or panel mount?
What is a Pole?
A pole is the input or common terminal. It is an electrically
isolated switching circuit.
Rotating Contact
Output
Terminals
Common
Pole
The rotating contact will channel the signal from the pole to the output
terminals. The number of output terminals required determines how
many positions a switch will have.
What is a Section?
A section is also referred to as the deck, wafer or module.
sections
Sections are made up of the common and position terminals of the switch.
Switches can be made of several sections to obtain multiple poles.
Poles vs Section
What is the difference between
enclosed and open frame?
In open frame switches the moving parts are visible. The
enclosed frame switches the parts are not visible.
– Open Frame switches have more flexibility on custom
contact configurations
– Open Frame have a bifurcated wiping or “self cleaning”
contact system ensuring reliable operation.
– Open Frame switches can have sections sold separately
– Enclosed Frame offers more protection from dust and
contamination
– Enclosed frame switches are generally less expensive
– Enclosed frame switches are generally more compact
Can you change the "Feel" or Torque of the switch?
Yes. Changing the spring or number of springs in many
switches will create a lighter or heavier detent actuation
“feel”.
spring
This is done during the manufacturing process at Electroswitch.
When Should You Specify Gold
Contacts?
Gold plated contacts should be used when your product
needs a longer shelf life.
Also, if the switch will not be actuated for a long period of
time after installation you may want gold contacts.
What is the difference between Current
Carrying Capacity & Current / Voltage Rating?
• Current carrying capacity, measured in amps, is the maximum load
that a switch will carry with the contacts in a closed position.
• Current / voltage rating is the tested amperage and voltage
capacity when switching contact positions under load (with
current). An electrical arc occurs when switching between positions
under load. Over a period of time, this arc may cause contact wear.
• A switch with the contacts closed has no arc, and the carrying
capacity is higher.
What is the difference between Shorting &
Non-shorting contacts?
Non-shorting contacts break
before make
(narrower contact)
Shorting contacts make
before break
(wider contact)
Different Stop Types
A stop limits the rotation of the switch to the desired number of positions.
• Fixed Stop
– Stops are built into the switch at the factory
– Better for volume production requirements so customer does not have to
adjust each switch
– These stops are not changeable by the customer
• Adjustable Stop
– Stop type where customer can adjust switch to desired number of positions
– Standard switches are supplied with adjustable stops preset at 2 positions
– Good Choice for low volume requirements
• Continuous Rotation
– Switch with no stops
Adjustable Stop Mechanisms
Can Electroswitch rotary switches
be water resistant sealed?
Yes. Most Switch series offer a shaft and panel seal option.
This allows the switch to be front panel sealed.
In addition, our C series switches have the option to be
completely sealed to meet an IP67 (submersion) rating.
Applications
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Test and Measurement
Pro and High end Audio
Military and Aerospace
Construction and Agricultural Equipment
Medical and Diagnostic Equipment
Transportation and Off Road Vehicles
• Military and Commercial Communication
Rotary switches can be used in many applications. A rotary switch offers an easy way to switch more
combinations than what is offered by other switches. It also offers the user a definite tactile feedback
for position location. Rotary switches are generally more robust than other types of switches or
potentiometers.
Rotary Switch Features
Choosing the Right Switch for Your Design
Many
available
options
Sealing to
Meet IP67
The Electroswitch C series is an ideal choice for enclosed switch requirements. The C series is an
economical option for lower current rotary switch needs. It is ideal for requirements that need a low profile
compact switch. The C series has many available options including BCD or binary coded decimal outputs,
water resistant sealing, push to turn and dual concentric shaft designs.
Enclosed TO5 Series
• Low Cost
• Smallest Switch, Only 362” in diameter
• Options include a boot seal which prohibits
contamination of contacts during cleaning.
Rotary Switch Features
Choosing the Right Switch for Your Design
Many
available
options
D1, D3 and
D4 made to
Mil Spec
The Electroswitch D series is the ideal choice for open frame switch requirements. This series has lots of
design flexibility. The D series has many available options including water resistant sealing and dual
concentric shaft options. The Electroswitch D1, D3 and D4 were originally designed to meet Mil Spec
requirements.
Rotary Switch Features
Choosing the Right Switch for Your Design
Unique Index
Angles
T-Slug Terminals
and
Tri Concentric
Shafts
Electroswitch has recently added several open frame series. These switches have unique features that
include; Unidex housing, T-Slug terminals, tri-concentric shafts, and uncommon index angles. Several of the
series also meet Mil spec requirements and have water resistant sealing options.
Unidex Housing
(A and F series)
Utilizing dual ball detent indexing on a rugged star wheel. This detent
offers 100,000 cycles of mechanical life, with the torque remaining
constant and crisp throughout the life of the switch.
Unidex Housing
“T” Slug Terminals
(SK, 7M & 4M Series)
• Wedgelock method of clip assembly
• Stronger, Longer Life Switch
• Patented "T" slug design eliminates rotation
and twisting of contacts
Stator
Electroswitch
“T” Slug
Terminals for
added strength
Tri-Concentric Shafts For Multiple Functions
(7M, LK and RK Series)
This assembly may consist of three switches in one frame or
two switches & a potentiometer within the same frame
limitations as a single shaft switch
Rotary Switch Features
Choosing the Right Switch for Your Design
Standard
Switches for:
Spring-Return,
High Current,
24 Position PC
mount
The Electroswitch E series has standard options for special requirements. The E5 series is designed to meet
the needs of a 24 position pc mount switch. The E3 series is a standard spring-return rotary switch. The E4
series has a current rating to switch 11 Amps @ 28VDC.
Rotary Switch Features
Choosing the Right Switch for Your Design
M6 and M7
can go up
to 32 and 48
positions
The Electroswitch M series were originally designed to meet Mil Spec requirements. These switches are used
in a variety of military, avionic and industrial applications. The M6 and M7 have the capability to go up to 32
and 48 positions.
Value-Added Options
•Special readouts (BDC or other)
•Made Specific to Drawing
•Special Testing / Ratings Required
•Overmolding
•Key Lock
•Cable Harness
•Sealing (to IP67)
•Special Grease (Temp or Life)
•Knurled Shaft
•Push to Turn Shaft
•Dual Concentric Shafts
Contact Digi-Key Design Support services:
http://dkc1.digikey.com/us/en/mkt/VBD/designsupport.html