Bring New Life to Used Electromagnetic Brakes

Alternative Solution to Your Motor Brake Problem

Each electromagnetic brake remanufactured by ICR Services – whether spring activated or magnetically activated – is designed and tested to provide the necessary amount of holding torque. Every motor brake rebuild ensures smooth and even contact, which is vital to lessen metal-to-metal wear: without this, you risk performance and are 2x more likely to experience premature failure.

Different types of motor brakes

Spring Activated Electromagnetic Brake Parts Explained

1. Friction Disc

The true composition of friction pads is tightly guarded. Maybe not as much as Colonel Sanders’ secret recipe spice-blend, or the formula to original Coke, but our efforts to get this composition just right is always top-of-mind.

Types of friction pads

It’s mostly fiber-based with fine pieces of rubber and flaked brass for structural integrity and proper heat dissipation.

    Spring Activated Motor Brakes: Friction Disc Types Explained
    1. Fiber Pad with Fibrous Hub
    2. Entirely made of fibrous material: toothed hub and all.

    3. Fiber Pad with Steel Hub
    4. Steel hub sandwiched between two thin fiber pads.

    Spring activated motor brake friction discs
    A Hand-crafted Journey

    Uncut sheets of fiber pad material arrive at our facility weekly. The motor brake remanufacturing team begins to create custom fittings by shaping the fibrous composite into various sized cylindrical rings using CNC technology.

    Brake servo disassembled
    Patience is Key

    Once the cut is complete and passes quality control checks, a thin layer of high-strength 2-part epoxy is applied to each cylindrical ring. The adhesive will bond the steel hub and cylindrical rings together (1 per side) to form the finished friction disc. This step is again tested and measured to ensure its placement is precise.

    Patience comes to play when the friction disc is placed in a dry heat treatment overnight. Shortening the drying process only jeopardizes electromagnetic brake performance.

2. Electromagnetic Coil

Iron Man fans will appreciate the chest piece looking part of the motor brake. This is where much of the weight and behind-the-scenes happenings take place.

Servo motor electromagnetic coil or winding

Springs clamp the friction surfaces together to apply the brake. With power restored, magnetic force from coil overcomes spring force, pulling the pressure plate away from rotor friction surface to release brake.

The brakes engage in unpowered condition and release when DC voltage is applied. When testing, we want the brake to release at 50% of the rated voltage – typically 12V or 45V for most motors. The ICR technician will mark both the release voltage and holding torque on the outside of the cover plate.

Motor brake housing

Since the electromagnetic coil is manufactured by outside producers, the checks and measures undertaken by ICR techs, before deeming them fit for recommissioning, are quite extensive.

Down to the Finest Details

Milled slots create the perfect home for our springs. Only industrial-grade compression springs can apply the necessary holding torque to clamp the friction surfaces together: this is not your everyday ballpoint trigger spring. You’ll typically see 6-8 springs per electromagnetic brake. Every spring is replaced during the rebuild process.

Servo motor brake winding needing repair
Yikes! This image shows an electromagnetic coil belonging to a servo motor in need of repair. You can see the material intended to protect the coil has started to deteriorate. With only a thin layer of epoxy remaining and wrapping widely left exposed, it’s very likely the winding itself has been jeopardized.

3. Pressure Plate and Cover Plate

Yes, these two pieces are strictly mechanical. Should they be considered inferior to the other components? Absolutely not.

Cover plate

The cover plate is closer to the rotor and will be on top of the friction disc (Pro tip: look for the screw holes, and you’ve found the right one). The pressure plate hangs out near the back, closer to the electromagnetic coil. In-between the machined steel plates is, of course, the one and only friction disc.

Defects Don’t Stand a Chance

Surfaces must be clean (rust buildup can be a problem here) and any imperfections likely to cause problems down the road must be dealt with upfront. A simple trip to the surface grinder can handle most cases, but for those requiring more extensive attention, we’re able to flex our machining muscles with more advanced techniques when needed.

Electromagnetic brake repair
Need a quick refresher course? The Spring Applied Brake Installation video produced by Ogura Industrial Corporation is one of the best electromagnetic brake videos we’ve come across.

4. Rated Air Gap

The rated air gap tolerance can be reduced to a few hundredths of a millimeter. We’re talking about exact measurements to provide enhanced holding torque. Since the rated air gap tolerance is already so tight (0.25 – 0.50 mm), we got our shop aprons back on and got creative.

Servo Motor Brake Repair Holding Torque and Rated Air Gap
A Challenge Well Worth It

Through our research and improved process the enhanced braking power provided by a reduced air gap can take ordinary holding torques of 12 – 18 Nm to new levels. Because of this breakthrough, the torque ratings customers have in their servo motor brake repairs are much higher at ICR Services.

When you want to know everything that’s been done to your motor while it was away, read your ICR Repair Report. We’re proud of the work that’s unseen. That’s why we test, measure, and report it to you.

Should I Get My Electromagnetic Brake Rebuilt?

We’ve talked with customers who feel stuck with going to the OEM given their current motor brake problem. You’re not stuck. You just need a repair partner who is paying attention.

We’ll recondition the brake housing and coil back to OEM specs. If its magnetism remains (and most of the time it does), motor brake rebuild is possible. A few machining touch-ups and remanufactured friction disc is sometimes all that is required.

The electromagnetic brake is just one of the many pieces involved in the refurbishment of a motor. Learn about the entire servo motor repair process in Is Your Servo Motor Repaired or Refurbished? for more insight and process know-how.

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