Speed Sensing
| Product Overview |
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Bulletin 808 Speed Switches
- Maximum Shaft Speeds up to 2000 RPM
- Adjustable Ranges from 15 to 1000 RPM
- Type 1, Type 4 & 13, and Type 7 & 9 Enclosures
- Variety of Mounting Arrangements
- Normally Open or Normally Closed Contacts
- Optional Lockout Solenoid
Standards Compliance and Certifications
Standards Compliance
UL 698 (Haz. Loc.)
UL 1604 (Haz. Loc.)
UL 508
CSA 22.2 No. 14
NEMA ICS-2
Certifications
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| File and Guide Numbers | ||||
| Bulletin 808 |
UL | CSA | ||
| File Number | Guide Number | File Number | Class | |
| E10314 (Haz. Loc.) E14840 |
NOIV, NOIV7 NKCR |
LR11924 (Haz. Loc.) LR1234 |
3218-02 3211-03 |
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| Hazardous Location Enclosures are not CE compliant. | ||||
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Description
Bulletin 808 Speed Switches are pilot devices used for detecting speed or direction of rotation. They are commonly used in applications requiring forward plugging, motor sequencing, and anti-plugging circuitry and are an effective means of detecting broken belts or couplings. Allen-Bradley Bulletin 808 Speed Switches utilize magnetic coupling technology to increase product life and reliability, eliminating the possibility of failure due to mechanical and hydraulic couplings that can wear or leak over time. Bulletin 808 Speed Switches are supplied as standard with a sealed outboard bearing and an additional external seal. The external seal reduces the effects of contaminants and increases the life of the device. Bulletin 808 Speed Switches offer a variety of mounting arrangements and have been designed to allow for easy speed adjustments in the field. Speed switches are not designed to sense shaft speed below 15 RPM, and will not sense zero shaft speed. Low RPM sensing can be achieved by modifying the shaft speed ratio via gearing or pulley arrangements. Speed switches wired for plugging applications achieve zero speed by employing the millisecond decay of the electromagnetic fields of the reversing starter and motor.
Applications
- Machine Tools
- Large Conveyors
- Punch Presses
- Material Lift Over/Under Speed
- Fan Rotation
- Pump Operation
Styles J and K — Low Speed Switches
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Style J
- Normally open contacts
- 1200 RPM maximum shaft speed
- Type 1, 4 & 13, and 7 & 9
- Variety of mounting arrangements
- Optional lockout solenoid
- 15…80 RPM adjustment range for contact operation
Style K
- Normally closed contacts
- 1200 RPM maximum shaft speed
- Type 1, 4 & 13, and 7 & 9
- Variety of mounting arrangements
- Optional lockout solenoid
- 15…80 RPM adjustment range for contact operation
Styles M and R — High Speed Switches
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Style M
- Normally open contacts
- 2000 RPM maximum shaft speed
- Type 1, 4 & 13, and 7 & 9
- Variety of mounting arrangements
- Optional lockout solenoid
- 50…1000 RPM adjustment range for contact operation
Style R
- Normally closed contacts
- 2000 RPM maximum shaft speed
- Type 1, 4 & 13, and 7 & 9
- Variety of mounting arrangements
- Optional lockout solenoid
- 50…1000 RPM adjustment range for contact operation
Typical Industrial Applications
Plugging — Stops a motor quickly. A speed switch with normally open contacts is used in conjunction with a contactor or starter wired to reverse the field windings of a squirrel cage motor. In plugging applications, the device, when properly adjusted to given conditions, will provide the control circuit logic to apply reverse energy to the motor to reach zero speed. The motor, electrical power distribution, and machine must be designed to handle sudden stopping.
Application examples include:
- Milling Machines
- Drill Presses
- Lathes
Anti-Plugging — Allows a machine to coast until it reaches a safe speed. A speed switch with normally closed contacts is wired into a suitable circuit. When properly set, the device will not allow reversing or apply braking, by a designated method, until the machine has reached a safe speed.
Application examples include:
- Punch Press Flywheels
- Large Machining Tables
Speed Sensing — Detects approximate shaft speed. The device with normally open or normally closed contacts can be used, in an appropriate circuit, to sense the approximate speed of a rotating shaft.
Application examples include:
- Conveyors
- Vertical Lift Equipment
Direction of Rotation — Detects direction of shaft rotation. The device can be wired into a circuit to sense clockwise or counterclockwise shaft rotation. Normally open or normally closed contacts can be used depending upon the requirements of the circuit.
Application examples include:
- Pump Rotation
- Ventilating Fans
Technical Data
Theory of Operation
When the shaft of a speed switch is rotated, a magnetic induction linkage operates a contact. One contact is provided for clockwise operation, and one contact for counterclockwise operation. See Figure 1 for a simplified view of the operating mechanism of a Speed Switch with normally open contacts. Operation of a device with normally closed contacts is similar.
When the shaft (1) rotates, the field of the magnet (2) induces eddy currents in the copper cup (3). These currents produce an electromagnetic torque proportional to the shaft speed, which produces a rotational torque on the cup in the same direction as the shaft rotation. The cup engages a contact operating lever (4) to activate the contacts.
As the shaft speed increases, the operating torque will also increase. When the torque has increased enough to overcome an opposing adjustable spring force (5), the moveable contact (6) is forced against the stationary contact (7). The contacts close and will remain closed as the shaft speed increases to its normal value.
Similarly, as the shaft speed is decreased, a speed is reached where the spring force again exceeds the operating torque and the contacts return to their normal position.
As the shaft speed increases, the contact set speed (the speed at which the contacts operate) will be at a higher RPM than the speed where the contacts reset (return to their normal position) on decreasing RPM. The difference in these contact operating values is called the differential.
Ambient Temperature Range
Temperatures below 32°F (0°C) are based on the absence of freezing moisture, water, or other fluids that may solidify and impede contact operation of the control. Temperature ranges are as follows:
Operating: –22…150°F (–30…66°C)
Storage: –22…200°F (–30…93°C)
Typical Control Circuits
Forward Plugging — Circuit shown in Figure 2 is a typical control circuit for forward direction plugging with optional lockout protection. Operation is as follows:
Pushing START energizes the forward coil and closes normally open contact F1; the motor runs forward. Normally closed contact F2 opens the circuit so the reverse coil does not energize. The forward contact on the speed switch closes. Pushing STOP drops out the forward contact. Then the reverse contactor or starter is energized and the motor is plugged. When the motor speed decreases to the preset speed setting of the speed switch, the contact opens and drops out the reverse contactor.
Conveyor Sequencing — Circuit shown in Figure 2 is a control circuit for conveyor sequencing. Operation is as follows:
Pushing START energizes coil M1 to start the first conveyor and closes the normally open contact. When the first conveyor reaches the preset speed setting of the speed switch, the speed switch contact closes, energizing coil M2 to start the second conveyor. Pushing STOP drops out coils M1 and M2, stopping the conveyors.
Anti-Plugging — Circuit shown in Figure 2 is a typical anti-plugging control circuit. The circuit is used where damage would result from a sudden reversal of power. Bulletin 808 contacts keep the reverse circuit open until the motor has coasted to a preset speed.
Figure 1
Operating Mechanism
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Figure 2
Typical Control Circuits
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Lockout Solenoid
In some applications, an accidental turn of the shaft may close the Bulletin 808 contacts that jog or start the motor. To guard against this, the Bulletin 808 can be equipped with a lockout solenoid, which mechanically restrains the contacts from operating unless the lockout coil is energized. This feature is available factory-mounted or in kit form. To order Lockout Solenoid, see Modifications and Accessories.
Mounting
The Type 1, 4 & 13 enclosure is available in three types of mounting brackets. They are base mounting, 3-point flange mounting and 4-point flange mounting. These devices are also available without mounting bracket for direct mounting. The Type 7 & 9 enclosure is available with base mounting only. Mounting brackets can be assembled at the factory, or ordered separately as accessories.
Installation
For greatest accuracy, the Bulletin 808 shaft should be driven at the highest available speed within its maximum operating speed. It is recommended that the continuous driven speed be at least two times the speed at which the contacts are set to operate. This will provide the torque to hold the contacts in the desired position, reducing false contact operation under severe shock and vibration. The driven speed can be higher than the adjustable range speed, but must not exceed the maximum shaft operating speed. There must be a positive coupling between the Bulletin 808 and machine. A rigid coupling should not be used. However, flexible couplings are recommended and available from local Power Transmission Equipment Distributors. Gears, chains, or timing belts can be used if it is not possible to mount a flexible coupling. A V-belt is not recommended for plugging applications.
Adjustment
The contact operating speed is easily adjusted with two external adjustment screws, one for each set of contacts. After the speed switch has reached normal operating temperature, the screw is turned to adjust the contact operating speed. Changes in inertia (WR2) of moving equipment may require readjustment of the set points.
Shaft Loading
If the radial and axial shaft loading values are exceeded, shortened bearing life may result. The maximum values are listed in the Maximum Shaft Loading table below. In speed sensing or direction of motion applications, a timing belt may be used. A V-belt is not recommended. Proper belt tension must be maintained to keep slippage at a minimum.
Maximum Shaft Loading
| Enclosure | Maximum Radial Loads | Maximum Axial Loads (Thrust Loads) |
| Type 1, 4 & 13 | 50 lbs. (222 Newtons) | 20 lbs. (89 Newtons) |
| Type 7 & 9 | 25 lbs. (111 Newtons) | 20 lbs. (89 Newtons) |
| Note:Timing belt tension must not exceed 25 lbs. (111 Newtons). | ||
Typical Torque and Temperature Rise Characteristics
| Contact Operating Range RPM |
Shaft Operating Speed Maximum RPM |
Driving Torque Maximum lb•in |
Temperature Rise (Maximum RPM) °F |
| 15…80 | 1200 | 6 (.68 N•m) | 120 °F (49 °C) |
| 50…1000 | 2000 | 6 (.68 N•m) | 140 °F (60 °C) |
Contact Ratings — NEMA B600
| AC | DC | ||||||
| Maximum AC Voltage |
Amperes | Continuous Carrying Current | Voltamperes | Maximum Voltage | Ampere | ||
| Make | Break | Make | Break | ||||
| 120 | 30 | 3.00 | 5 | 3600 | 360 | 115…125 230…250 |
0.12 0.08 |
| 240 | 15 | 1.50 | 5 | 3600 | 360 | ||
| 480 | 7.5 | 0.75 | 5 | 3600 | 360 | ||
| 600 | 6 | 0.6 | 5 | 3600 | 360 | — | — |
Contact Wiring Configurations
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Ordering Information
Ordering Bulletin 808 Speed Switches
When ordering Bulletin 808 Speed Switches, select a catalog number for the device that meets your application requirements. If modifications are required, add the appropriate modification suffix codes to the catalog number. Accessories are ordered as separate catalog numbers. Note:Lockout solenoid can be ordered as a factory installed modification or as an accessory in kit form. See Modifications.
How to Order
Step 1: Basic Device
Select a catalog number for the basic device. See and .
Step 2: Modifications
If required, add the appropriate modification suffix code(s) to the catalog number of the basic device. See Ordering Modifications.
Step 3: Accessories
If required, order accessories as separate catalog numbers. See Accessories.
Catalog Number Explanation
Note:Catalog numbers must not include blank spaces.
| 808 | – | K | 1 | 7 | LA1 | X1 | W5 | |||||
| a | b | c | d | e | f |
| a | |
| Style of Device | |
| Code | Description |
| J | See Description, Product Overview |
| K | |
| M | |
| R | |
| b | |
| Mounting Arrangements | |
| Code | Description |
| 1 | Base |
| 2 | 3-point Flange |
| 3 | 4-point Flange |
| 4 | Direct Mounting (Less Bracket) |
| c | |
| Enclosure Type | |
| Code | Description |
| Blank | 1, 4, and 13 |
| 7¬ | 7 and 9 |
¬ Available only with Mounting Arrangement 1
| d | |
| Lockout Solenoid Modification | |
| Code | Description |
| LA24 | 24V AC 60 Hz |
| LA1 | 110/120V AC 50/60 Hz |
| LA20 | 208V AC 60 Hz |
| LA2 | 220/240V AC 50/60 Hz |
| LA4 | 440/480V AC 50/60 Hz |
| LA6 | 550/600V AC 50/60 Hz |
| e | |
| Modification 2 | |
| Code | Description |
| X1 | Optional, Speed Switch with Bottom Conduit Opening |
| f | |
| Modification 3 | |
| Code | Description |
| W5 | Optional, Speed Switch without External Shaft Bearing Seal |
Product Selection
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| Style J — Low Speed, N.O. Contacts | ||||
| Mounting Arrangement | Range of Adjustment for Contact Operation (RPM)¬ | Shaft Operating Speed, Max. (RPM) | Type 1, 4, & 13 Enclosure |
Type 7 & 9 Enclosure§ |
| Cat. No. | Cat. No. | |||
| Base | 15…80‡ | 1200 | 808-J1 | 808-J17 |
| 3-Point Flange | 15…80‡ | 1200 | 808-J2 | — |
| 4-Point Flange | 15…80‡ | 1200 | 808-J3 | — |
| Less BracketT | 15…80‡ | 1200 | 808-J4 | — |
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| Style K — Low Speed, N.C. Contacts | ||||
| Mounting Arrangement | Range of Adjustment for Contact Operation (RPM)¬ | Shaft Operating Speed, Max. (RPM) | Type 1, 4, & 13 Enclosure |
Type 7 & 9 Enclosure§ |
| Cat. No. | Cat. No. | |||
| Base | 15…80‡ | 1200 | 808-K1 | 808-K17 |
| 3-Point Flange | 15…80‡ | 1200 | 808-K2 | — |
| 4-Point Flange | 15…80‡ | 1200 | 808-K3 | — |
| Less BracketT | 15…80‡ | 1200 | 808-K4 | — |
| ¬ The continuous driven speed should be at least two times the speed at which the contacts are set to operate. This driven speed can be higher than the range indicated, but must not exceed the maximum shaft operating speed. | ||||
| T For direct mounting or with mounting accessory bracket. | ||||
| ‡ When mounting speed switch with the adjusting screws in a vertical plane, rather than the standard horizontal plane, the minimum adjustable speed is 20 RPM. | ||||
| § Enclosure Rating: Class I Groups C, D. Class II Groups E, F, G | ||||
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| Style M — High-Speed, N.O. Contacts | ||||
| Mounting Arrangement | Range of Adjustment for Contact Operation (RPM)¬ | Shaft Operating Speed, Max. (RPM) | Type 1, 4, & 13 Enclosure |
Type 7 & 9 Enclosure‡ |
| Cat. No. | Cat. No. | |||
| Base | 50…1000 | 2000 | 808-M1 | 808-M17 |
| 3-Point Flange | 50…1000 | 2000 | 808-M2 | — |
| 4-Point Flange | 50…1000 | 2000 | 808-M3 | — |
| Less BracketT | 50…1000 | 2000 | 808-M4 | — |
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| Style R — High-Speed, N.C. Contacts | ||||
| Mounting Arrangement | Range of Adjustment for Contact Operation (RPM)¬ | Shaft Operating Speed, Max. (RPM) | Type 1, 4, & 13 Enclosure |
Type 7 & 9 Enclosure‡ |
| Cat. No. | Cat. No. | |||
| Base | 50…1000 | 2000 | 808-R1 | 808-R17 |
| 3-Point Flange | 50…1000 | 2000 | 808-R2 | — |
| 4-Point Flange | 50…1000 | 2000 | 808-R3 | — |
| Less BracketT | 50…1000 | 2000 | 808-R4 | — |
| ¬ The continuous driven speed should be at least two times the speed at which the contacts are set to operate. This driven speed can be higher than the range indicated, but must not exceed the maximum shaft operating speed. | ||||
| T For direct mounting or with mounting accessory bracket. | ||||
| ‡ Enclosure Ratings: Class I Groups C, D. Class II Groups E, F, G | ||||
Modifications and Accessories
Ordering Modifications
Modifications are ordered by adding the appropriate modification suffix code to the catalog number of the basic device. Add suffix codes to the catalog number in descending order.
Modifications
| Lockout Solenoid | |||
| Description | Coil Voltage AC | Hz | Suffix Code |
| In some applications, an accidental turn of the shaft may close the contacts and jog or start the motor. To guard against this, Bulletin 808 Speed Switches can be equipped with a lockout solenoid, which mechanically restrains the contacts from operating until the lockout coil is energized. To order, select a suffix code to identify the operating voltage and frequency of the lockout coil. Add the suffix code to the catalog number before any other modifications. | 24 | 60 | LA24 |
| 110/120 | 50/60 | LA1 | |
| 208 | 60 | LA20 | |
| 220/240 | 50/60 | LA2 | |
| 440/480 | 50/60 | LA4 | |
| 550/600 | 50/60 | LA6 | |
| Speed Switch without External Shaft Bearing Seal | |
| Description | Suffix Code |
| The external bearing seal can be omitted at the factory if it causes mechanical mounting interference. Omitting the external seal will increase the usable shaft length from 1.05" (26.7 mm) to 1.38" (35 mm) permitting mounting the speed switch directly to an end bell housing. To order device without the external seal, add suffix code W5 to the end of the catalog number after all other modifications. |
W5 |
| Speed Switch with Bottom Conduit Opening | |
| Description | Suffix Code |
| In addition to the standard conduit openings on each side, an additional opening at the bottom can be supplied. To order, add Suffix Code X1 to the basic catalog number. Note: Not available for Type 7 & 9 enclosures. | X1 |
Ordering Accessories
Accessories are ordered as separate catalog numbers. Select the appropriate accessories from the tables below.
Accessories
| Replacement Bearing Seal | |
| Type | Cat. No. |
| Replacement Bearing Seal | 808-N5 |
| Mounting Brackets | |
| Type | Cat. No. |
| Base Mounting | 808-N1 |
| 3-Point Flange | 808-N2 |
| 4-Point Flange | 808-N3 |
| Lockout Solenoid Kit | |
| Description | Cat. No. |
| To order a Lockout Solenoid Kit, add the appropriate lockout solenoid suffix code (see Lockout Solenoid table under Modifications) to Cat. No. 808-N_. Example: to order a Lockout Solenoid Kit for a device operating at 110/120V AC, 50/60 Hz, the complete Cat. No. is 808-NLA1. | 808-N_ (Catalog number must include a lockout solenoid suffix code) |
Approximate Dimensions
Dimensions in inches (millimeters). Dimensions are not intended to be used for manufacturing purposes.
Type 1, 4, & 13
Figure 1 — Less Mounting Bracket
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| Less Mounting Bracket | |
| Cat. No. | |
| Without Lockout Solenoid | With Lockout Solenoid¬ |
| 808-J4 | 808-J4L |
| 808-K4 | 808-K4L |
| 808-M4 | 808-M4L |
| 808-R4 | 808-R4L |
Figure 2 — Base Mounting
|
| Base Mounting | |
| Cat. No. | |
| Without Lockout Solenoid | With Lockout Solenoid¬ |
| 808-J1 | 808-J1L |
| 808-K1 | 808-K1L |
| 808-M1 | 808-M1L |
| 808-R1 | 808-R1L |
¬ If lockout solenoid is used, see dotted portion of Figure 1 for dimensions.
T If speed switch is without the external shaft bearing seal (suffix W5), this dimension would be 1-3/8 (34.9).
‡ Bulletin 808 Speed Switches with a suffix X1 added to the catalog number are equipped with a 1/2 (12.7) pipe tap in the center of the enclosure bottom on the same center line as the pipe tap at the side.
Approximate Shipping Weights
- Without lockout solenoid: Type 1, 4 & 13: 6 lbs (2.7 kg); Type 7 & 9: 10 lbs (4.5 kg)
- With lockout solenoid: Type 1, 4 & 13: 7-1/2 lbs (3.4 kg); Type 7 & 9: 11-1/2 lbs (5.2 kg)
Dimensions in inches (millimeters). Dimensions are not intended to be used for manufacturing purposes.
Type 1, 4, & 13 (continued)
Figure 3 — Flange Mounting (Three-Point)
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| Flange Mounting (Three Point) | |
| Cat. No. | |
| Without Lockout Solenoid | With Lockout Solenoid¬ |
| 808-J2 | 808-J2L |
| 808-K2 | 808-K2L |
| 808-M2 | 808-M2L |
| 808-R2 | 808-R2L |
Approximate Shipping Weights
Without lockout solenoid — 6 lbs (2.7 kg)
With lockout solenoid — 7-1/2 lbs (3.4 kg)
Figure 4 — Flange Mounting (Four-Point)
|
| Flange Mounting (Four Point) | |
| Cat. No. | |
| Without Lockout Solenoid | With Lockout Solenoid¬ |
| 808-J3 | 808-J3L |
| 808-K3 | 808-K3L |
| 808-M3 | 808-M3L |
| 808-R3 | 808-R3L |
| ¬ If lockout solenoid is used, see dotted portion of Figure 1 (on previous page) for dimensions. | |
Approximate Shipping Weights
Without lockout solenoid — 6 lbs (2.7 kg)
With lockout solenoid — 7-1/2 lbs (3.4 kg)
Type 7 & 9
Figure 5 — Base Mounting
|
| Base Mounting | |
| Cat. No. | |
| Without Lockout Solenoid | With Lockout Solenoid |
| 808-J17 | 808-J17L |
| 808-K17 | 808-K17L |
| 808-M17 | 808-M17L |
| 808-R17 | 808-R17L |
Approximate Shipping Weights
Without lockout solenoid — 10 lbs (4.6 kg)
With lockout solenoid — 11-1/2 lbs (5.2 kg)