Rotary and Key Lock Switches
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An overview introduction to rotary switches and mechanical encoders
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Rotary and Key Lock Switches
- 7. Types of Single Deck Rotary Switches Series 50 and 51 Series 56 Series 5000 Series 24 Series 19
- 17. Mechanical Encoders 4-bit GRAY Code 4-bit Hexadecimal Code Mechanical Encoder
- 19. Mechanical Encoders Series 71, 51, and 26
Editor's Notes
- This is a training module on Grayhill Rotary and Key Lock Switches
- Welcome to the training module on Grayhill rotary switches. This training module introduces the workings of a rotary switch, and its terminology and applications. This also introduces different types of rotary switches.
- A rotary switch is an electromechanical device which is capable of selecting, making or breaking an electrical circuit. A typical deck section consists of a common pole and it’s integral terminal, switch position terminals and a moving contact mounted to the shaft. In an actual switch, the moving contact touches the selected switch position terminal and the common pole. As the shaft is rotated, the moving contact is moved between the switch position terminals. The detent system of a rotary switch provides an operator with a positive indication of rotation from one switch position to the next .
- The common pole or “pole” is the terminal that is common to two or more terminals. A rotary switch can have more than one pole as shown here. The “throw” of a rotary switch is the number of switch position terminals per pole. This is a single pole, twelve throw switch. It could also be called a single pole, twelve position switch .
- Grayhill rotary switches are available with either non-shorting or shorting contacts. The terminals that remain stationary during shaft rotation are called the fixed contacts. The contact that rotates from on switch position to the next is called the moving contact. In a non-shorting switch the moving contact breaks the connection with the previous fixed contact before it makes the connection with the next fixed contact. This type of contact is also called “break before make” or BBM. In a shorting switch the moving contact makes the connection to the next fixed contact before it breaks the connection with the previous fixed contact. This type of contact is also called “make before break” or MBB .
- This page gives the features of a single deck rotary switch. Grayhill single deck rotary switches are compact and economical rotaries that require minimal panel space. These are high quality, enclosed switches available in MIL-spec versions for demanding applications. They can be specified as fixed stop. Adjustable stop, or continuous rotation, custom shafts, configurations, and sealed assemblies are also available.
- Grayhill has a full line of single deck rotary switches. They are Series 75, 50,51, 56, 5000 and 24,19. The series 75 is our smallest rotary switch with a life rating of 10,000 cycles at 200mA. Applications include military, telecomm and power transmission equipment . The series 50 and 51 is a half inch rotary switch with a life rating of 25,000 cycles at 200mA. The series 56 is a lower priced, commercial version of the series 50 and 51 . The Grayhill series 5000 and 24 are one inch diameter rotary switches with a life rating of 25,000 cycles at 1A.
- Series 50 and 51 switches have been used in military applications, including communication equipment, Bore sighting devices, night vision devices, and laser aiming lights. They can also be used in medical equipment such as dental curing lights and oxygen monitors . Series 5000 and 24 switches have been used in test and measurement equipment, power transmission equipment, stage lighting systems, sport hunting lights and welding machines . Series 19 switches are used in applications like home appliances, power transmission equipment, battery chargers, test equipment, power supplies and commercial air cleaning equipment .
- Grayhill's multi-deck rotary switches provide almost unlimited circuitry options through unique combinations of decks, poles per deck and positions per pole as well as concentric shafts. They can be specified as fixed stop, adjustable stop, or continuous rotation. Electrical specs can be chosen from low current (wiping contacts) to high current (UL type) to fit your application. Custom shafts, configurations, sealed assemblies and MIL-spec versions are also available. The series 8 and 9 is a half inch rotary switch capable of switching a quarter amp for 25,000 cycles . The series 71 was originally designed as a commercial version of the series 8 and 9 rotary switch. Later it was also qualified to military specifications, it is a quarter amp, 25,000 cycle switch.
- This page outlines Series 53, 57, 59, 42, 43, 44, and 54. C ustomer demand for quarter amp rotary switches in 16, 20 and 24 position configurations led to the introduction of the Series 53, 57 and 59. These products have a rated life of 25,000 cycles. They are military qualified and used in military and avionics applications . Series 42, 43, 44 and 54 are one amp switches. These are military qualified products with a rated life of 25,000 cycles .
- Here we show some applications of the multi-deck rotary switch, including series 71, which can be used in telecommunication amplifiers, emergency radios, military communications, electric guitars, test and measurement, avionics, military, medical and surveillance equipment a nd audio mixing consoles. Series 8 and 9 are military qualified and suitable for military and avionics applications . Series 42, 43, 44 and 54 applications include military, avionics, test and measurement and audio-video equipment.
- Grayhill special function rotary switches include spring return and isolated position versions. This includes series 8 and 9, series 42 and 44 and the series 50 and 51 can be made with spring return shafts or isolated positions . A spring return rotary switch has one or more momentary positions. The operator must apply a constant rotational force to hold the shaft in the momentary position. If the operator let’s go of the shaft knob, the shaft “springs back’ to it’s original position. This feature is required when a “hold to test” or “hold to calibrate” function is required in the application . It has choice of configurations, ratings, styles and circuitry and has 10,000 cycles of operation.
- The isolated position rotary switches are available with pull-to-turn or push-to-turn functions. An isolated position is one which cannot be reached by the normal rotation. An additional action is required by the operator. It could be either push-to-turn, or pull-to-turn. After the switch is rotated to the isolated position, releasing the shaft locks the switch in that position. Push or pull again to rotate the switch again. Use isolated positions to protect a switch position from indiscriminate rotation. Such safety positions might include “calibrate”, “off” and / or “stand-by”.
- Key lock switches are rotary switches with a key lock added. Their performance specifications are similar to the base rotary switch from which they are constructed. They are used to prevent unauthorized switching. Applications for key lock switches include secure computer terminals, elevators and any device where access to switching needs to be limited to authorized personnel.
- This page outlines the features of the 71J and 71L series. All locks have identical keys unless specially ordered otherwise. Key removal for 30° throw has position 1 and 180°. Special key removal can be done at every 90°. For 36° throw it can be for all positions. Special key removal can be for position 1 only.
- This page outlines the features of 44L series. Each lock is keyed differently and key removal is done in all position. Special options of flat key with 90° or 180° increment key removals; 7 thru 12 decks.
- This page introduces mechanical encoders. The design and construction of mechanical encoders is similar to rotary switches. Output digital codes can be read by microprocessors. There is a common terminal and four additional terminals that could also be referred to as “bits” . The four bits are called the 1-bit, 2-bit, 4-bit and 8-bit. If the first ten positions are used, the encoder is said to output BCD code . These encoders are also available in codes called octal compliment, BCD compliment or hexadecimal compliment. As the mechanical encoder shaft is rotated from one position to the next, the encoder will momentarily generate some of the other output codes before it comes to rest in the detent position of the desired output code .
- Grayhill's 25B multi-deck mechanical encoder outputs a code called quadrature which happens to be the same output code used in most Grayhill optical encoders. BCD and gray code are available as standards on the 16 position models. Its application includes avionics navigation systems, commercial oven controls and medical devices . 25L series product outputs quadrature code and is also available with BCD and gray code on the 16 position models.
- Grayhill was able to adapt the series 71 and 51 rotary switches to provide code output. Later the 26 series was designed specifically as a mechanical encoder. Grayhill continues to offer all of these as standard catalog products . The series 26 has been incorporated into electric guitars and audio mixing consoles. The series 51 has been used in military and medical applications. The series 71 has been used in military and machine tool applications .
- Here are some of the applications of mechanical encoders. Its products include medical devices, hand held radios, automotive test equipment and process controls. The series 26 has been incorporated into electric guitars and audio mixing consoles. The series 51 has been used in military and medical applications. The series 71 has been used in military and machine tool applications. The low cost series 25L has been used in home appliances and automotive climate controls.
- Generally, the customer attaches a knob to rotary switches and mechanical encoders in virtually all applications. Grayhill offers knobs in various shapes, sizes, materials and mounting methods .
- Thank you for taking the time to view this presentation on “Rotary Switches ” . If you would like to learn more or go on to purchase some of these devices, you may either click on the part list link, or simply call our sales hotline. For more technical information you may either visit the “Grayhill” site, or if you would prefer to speak to someone live, please call our hotline number, or even use our ‘live chat’ online facility. You may visit Element 14 e-community to post your questions.