What Are Solenoid Brakes?
Stearns solenoid actuated brakes (SAB) are spring set, electrically released motor brakes that ensure automatic stopping and holding anytime power to the brake is interrupted.
Stearns is the market leader for solenoid brakes, and the primary supplier to all US motor manufacturers.
Advantages of Solenoid-Actuated Brakes
SABs have a compact design, delivering high torque in a small size. They are the standard choice for rapid-acting brakes in dynamic or holding applications and offer the widest range of options for specific applications.
Additional advantages include:
- Standard AC voltage; DC voltages available
- Direct mounting to electric motor (or foot mount)
- Direct mounting to NEMA C-face motors without special alignment procedures
- Overall torque range of 1.5 - 1,000 lb-ft
- Fast, positive response times for set & release with no residual drag
- Trademarked & patented friction discs with molded ring for easy visual identification
- Friction material is non-asbestos (as with ALL Stearns products)
- Maintained manual release with automatic reset
- Models for hazardous location, washdown, marine, maritime & Naval applications
- Available in a variety of enclosures including standard or dust-tight/waterproof
Unitized construction makes servicing friction discs easy - only screwdriver and wrench - so you can quickly do onsite friction disc replacement (as well as coils). SABs are also easily repairable with readily available replacement parts.
Explore solenoid brake types below, find a distributor or contact us with questions.
Solenoid Brake Enclosure Types
Stearns supplies solenoid actuated brakes in a variety of IP ratings.
Solenoid Selection
The brake solenoid must be closely sized to load requirements for maximum service life:
- An undersized solenoid (where load exceeds solenoid force) will fail through burnout of coil.
- An oversized solenoid (where solenoid force greatly exceeds load) will fail prematurely through hammering of the plunger on the frame.
Stearns engineers are specialists in applying the proper solenoid to a particular application. You can profit from our experience by having a Stearns engineer review your requirements and determine the best possible solenoid for your particular application. Frequently, Stearns engineers are able to offer valuable recommendations which lower your solenoid costs and improve the performance of your products.
View or Download Solenoid Specs Contact a Stearns Engineer
Manually Adjusted Solenoid Actuated Brakes
Stearns manually adjusted solenoid brakes have all the features you want most in spring-set electrically released disc brakes, including:
- Stearns-exclusive spring design for universal mounting
- Patented splined hub design increases friction disc working area, runs quieter & offers enhanced head dissipating capability
- Simple 2-wire motor connection
- Air gap adjustment gauge for visual recognition that the brake needs adjustment
- Maintained manual release with automatic reset
Stearns offers three SAB series with a manually adjusted design:
Self-Adjusting Solenoid Actuated Brakes
Stearns solenoid actuated spring-set disc brakes were the first in the industry to include an effective self-adjusting mechanism, and we are the ONLY brake manufacturer to offer self-adjusting brakes and produce our own friction discs.
Remote/inaccessible locations or high-cycling applications require a specially designed, low-maintenance brake that will operate at peak efficiency and provide uniform braking for long periods of time. Our self-adjusting SAB products are best-in-class because they require less maintenance and provide greater uptime on a torque-to-torque basis.
Stearns exclusive self-adjusting feature minimizes the major cause of brake maintenance by automatically compensating for friction lining wear.
This greatly reduces brake maintenance by eliminating the time required to periodically adjust the brakes for wear—especially if the brake is mounted on a hoist on the ceiling of a plant, or in another hard-to-reach area.
In addition, self-adjusting brakes are well suited for applications where rapid cycling requires frequent resetting of the solenoid air gap. Automatic adjustment also eliminates the potential for errors with hand adjustment.
Our self-adjusting solenoid brakes can be easily modified to suit your particular application. Depending which series you select, they can be directly mounted on motors ranging in size from NEMA 182TC through NEMA 505C.
Many modifications for special application requirements are available. We also have models specifically designed for marine and maritime applications (ABS Type Approval Certified). There are nine series of Stearns self-adjusting brakes to select from:
Double C-Face Disc Brake Couplers
Stearns disc brake couplers provide maximum versatility, allowing you to add a solenoid actuated brake to a C-face motor with a single shaft extension. Using our reliable brake couplers, you can couple a C-face motor to a C-face gear reducer.
Explore Double C-Face Coupler Brakes
Solenoid Brakes with Optional Encoder
Stearns solenoid actuated brakes are available with an internally mounted encoder. Encoders can also be adapted externally.
- Available in frame sizes 182TC - 505TC
- Cast aluminum housing meets IP 56 requirements
- All enclosure ratings available, including hazardous location
- Optimized for cool temperature operation
- Separate conduit exits provided for the brake & encoder leads to minimize potential electrical interference
- Choice of encoder manufacturers - Dynapar & BEI
Stearns brakes with internal encoders should be purchased through the motor manufacturer, as a special shaft length and diameter may be required. To order the brake-motor package, specify the brake model and encoder option.
View Encoder Brake Specs
Solenoid Washdown Brakes
In addition to our application-specific solenoid brakes at the top of this page (marine, maritime, Navy, and explosion proof) we also offer solenoid brakes that meet AAA Dairy Standards and other food industry washdown requirements. Our 56,000 Series and 87,000 Series brakes feature stainless steel hardware, neoprene gasketing and FDA-approved white epoxy paint or stainless steel enclosure.
Solenoid Brake FAQ
Get answers to common questions about our solenoid actuated brakes.
How do solenoid brakes work?
Stearns solenoid actuated brakes are spring set motor brakes controlled by an electrical solenoid. A solenoid is a device that converts electricity into mechanical motion, using a wire coil and plunger inside a housing. When an electrical current flows through the copper wire it creates a magnetic field. The housing concentrates the magnetic field, drawing the plunger down and releasing the brake. When the electric current is turned off, the spring engages the brake.
Does Stearns offer any circuit protection for EMI generated by a solenoid actuated brake coil?
Yes, we can provide a line filter. Just call Stearns product support and advise the part number for the brake coil, or the model number for the brake.
Does Stearns supply coils for special voltages for solenoid actuated brakes?
Yes. Please consult the Stearns catalog for standard coil voltages for each model and size of brake. Stearns coils are manufactured in house in Cudahy, WI. We have the capability to design and manufacture to OEM specifications for application specific requirements. Contact Stearns for details and to discuss your applications.
What do the colors of the pressure spring mean?
Each pressure spring for Stearns SABs is color-coded to indicate the torque rating of the brake, for example:
- 56,000 series - Green spring is for 1.5 & 3 lb-ft brakes, clear coated (silver) spring is for 6 & 10 lb-ft brakes & the gold spring is for 15, 20 & 25 lb-ft brakes.
- 87,000 series - Black spring is for 6 & 10 lb-ft brakes, white spring is for 15 lb-ft brakes, orange is for 25 & 50 lb-ft brakes & purple is for 35, 75 & 105 lb-ft brakes.
- 82,000 series - Green spring is for 125 lb-ft brakes, yellow springs are for 175 & 230 lb-ft brakes & the red spring is for 330 & 440 lb-ft brakes.
- All 86,000 series brakes have red springs (500 lb-ft, 750 lb-ft & 1000 lb-ft).
Why can’t I adjust the solenoid air gap on my 81 or 82 series brake?
Most likely the caution warning on the support plate that instructs to secure the solenoid plunger to the solenoid frame prior to loosening the support plate mounting screws was not followed, and the self-adjust mechanism allowed the lever arm to spring out from the support plate. In this case, the lever arm may need to be reset. See reference PDF.
Why can’t I adjust the solenoid air gap on my 87 series brake?
Most likely the caution warning on the support plate that instructs to secure the solenoid plunger to the solenoid frame prior to loosening the support plate mounting screws was not followed, and the self-adjust mechanism allowed the lever arm to spring out from the support plate. In this case, the lever arm may need to be reset. See reference PDF or video tutorial.
Why did the cotter pin in my 87 series brake shear off?
The cotter pin in the 87,000 series brake is there as a gentle keeper to keep the solenoid link from sliding off of the solenoid lever. It sees no impact or side load. When the pin is installed at the Stearns factory, it is slightly spread open just enough to keep it from slipping through the cotter pin hole. If the cotter pin has broken, it can only be the result of weakening the cotter pin, by either bending it too far, removing and reinstalling it and thus stressing the metal.
Solenoid Actuated Brakes in as Few as 5 Days
Solenoid actuated brakes in our Signature Series are based on industry demand for standard features and can be received as quickly as five business days. Our Signature Series program improves operational flexibility and reduces risk with locally manufactured and supported product lines.
Filter through our Signature Series SAB products by lead tIme and other popular product features to request a quote. Our experts are available to partner with you to find the best products for your applications.
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