Adhesives for Electric Motors

Yes, of course, there is magnet bonding. But there are many more applications for adhesives in electric motors than this. Permabond adhesives and sealants bond magnets, seal endplates, retain
bearings, pot, reinforce wires, and motor laminations. Adhesives are preferred over soldering, riveting, mechanical fasteners, tapes, and all types of welding (metal, ultrasonic, and solvent.) Here’s why:

Electric Motor Adhesive Advantages

•  Increase motor life; they will not fracture magnets
• Increase material selection; they bond dissimilar substrates
• Reduce hazards associated with solvents and metal welding
• Improve aesthetics/appearance
• Increase process speed
• Prevent vibration noise
• Prevent corrosion
• Reduce cost

Following, I’ll break down the types of applications and why adhesives are preferred.

Electric Motor Retaining Applications

Anaerobic retaining compounds structurally join, unitize, and permanently bond cylindrical parts. The reasons engineers prefer retaining the rotor components onto the motor shaft with anaerobic adhesives and sealants over joining via frictional or mechanical methods, is because these adhesives:

• Augment slip fits
• Mount bearings
• Restore correct fit
• Prevent corrosion
• Reduce machining time due to relaxed tolerances
• Enable rapid, quick, and easy assembly of parts
• Ensure 100% surface-to-surface contact
• Allow for greater load carrying capacity

Here are some of the popular retaining compounds:

Electric Motor Wire Reinforcement

Protect against wire breakage with structural epoxy adhesives. Epoxies provide a higher degree of protection against critical wire failure than solvent-based varnishes. It is especially important to reinforce the wires connecting to the commutator in DC motors that will perform in high vibration environments or where you expect flexing fatigue.

• High strength protection against wire breakage
• Eliminate solvents
• Heat cure and room temperature cure products available

Electric Motor Lamination Bonding

• Eliminate hum
• Reduce interlaminar loss
• Prevent corrosion

Engineering requirements vary greatly, therefore Permabond manufactures various adhesives for electric motor laminations including single component epoxies, surface activated acrylics, cyanoacrylate, and UV/Anaerobic cure adhesives to meet your processing and finished goods needs.

Potting Adhesives for Electric Motor Applications

Permabond has several chemistries that are ideal for various potting applications to encapsulate areas from the environment. Potting protects components from impact, vibration fatigue, thermal shocks, and corrosion, as well as helping to:

• Prevent dust and moisture ingress
• Eliminate corrosion
• Protect from impact stresses
• Reduce thermal shock
• Eliminate vibration fatigue

Threadlocking

Prevent vibration loosening of  bolts, cover screws, and all motor assembly fasteners with anaerobic threadlockers. Anaerobic threadlockers are common adhesives for electric motors as they outperform other methods of locking fasteners. They help to:

• Prevent vibration loosening
• Prevent corrosion
• Reduce cost
• Reduce weight
• Controlled strength – (permanent and removable grades)

See Threadlockers

Electric Motor Thread Sealing

Seal and lock metal pipe fittings and junctions with anaerobic thread sealants. These sealants offer the following advantages to pipe dope, specialty fittings, and PTFE tape:

• Fully cured sealants typically seal to the burst pressure of the pipe
• Will not shred, creep, or relax over time
• Reliable seal
• No solvents
• Reduce cost
• No loose particles to clog valves
• Resistant to a wide variety of chemicals
• Lubricates for easier assembly and allows accurate positioning of pipes
• Grades available for water, gas, air, and hydraulic systems

See Thread sealants

Tacking

Cyanoacrylates are preferred to tack wires, paper sleeves, insulation, etc., into place to hold them in the proper position during assembly. They are also used to reinforce wires and other fragile components.

Find a complete list of Permabond cyanoacrylates here.

And last but not least…

Electric Motor Magnet Bonding (and General Bonding)

Depending upon what type of manufacturing process you prefer, Permabond can recommend a product that will not only meet your end requirements but also allow you an efficient manufacturing process. Following are a few industry favorites.

Permabond Epoxies Permabond epoxy adhesives form strong, durable bonds which withstand temperatures up to 355°F (180°C).

Permabond ES550 is a non-sag epoxy, and ES568 is free flowing. Free flowing epoxies can be applied to the joint on top of the assembled can and magnet. When exposed to heat during cure, the epoxy flows prior to curing to fill the space between the two components. Non-sag epoxies are applied between the joint and will not flow during cure.

Permabond Surface Activated Structural Acrylics Permabond structural acrylics develop strength rapidly, so parts can be unclamped quickly. Then they continue to develop strength for 24 hours. Examples of Permabond’s surface activated acrylic line include TA437, TA439, and TA4590. The adhesive is applied to one surface, and the initiator is brushed or sprayed onto the other surface. Upon assembly, strength development occurs rapidly. Permabond TA437 can be used without the initiator, provided at least one surface is metal. However, strength development is faster with initiator.

Permabond External Mix Structural Acrylic High speed production lines benefit from the single dispense step and very fast strength development of Permabond TA4592. External mix dispensing equipment dispenses both components of TA4592 into a single stream. The components mix in the air before dispensing on the bond area.

Permabond Cyanoacrylates The expanding variety of small motors includes motors with unconventional substrates. For many of these motors, cyanoacrylates are ideal as they bond a variety of substrates quickly.