I am interested in buying electric motor components separately so I can add my own bearings, not use a motor with sealed OEM bearings.

I do not know the correct terminology for this type of application, so I do not know how to search for it.

How can I find motors like this?


closed as unclear what you're asking by alephzero, Dave Tweed, wwarriner, hazzey, Fred Oct 17 '16 at 11:31

Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

  • $\begingroup$ There are many different types of electric motor. Without knowing what type you want to build, and relevant parameters like the electricity supply (DC? Single or 3-phase AC?) the power (milliwatts or megawatts) and RPM you want (could be anything from 1 to 100,000 RPM) , the physical size constraints on the motor, etc, this is unanswerable. $\endgroup$ – alephzero Oct 15 '16 at 20:13
  • $\begingroup$ @alephzero It doesn't matter what kind of motor. I want to know the TERMINOLOGY for getting a customizable motor that does not have bearings. The terminology will be the same for all motors. I need a search term. $\endgroup$ – Wallace Park Oct 15 '16 at 20:21
  • $\begingroup$ The question was How can I find motors like this?. Since you gave no clues as to what "motors like this" really meant, the question was unanswerable - except by yourself, since you presumably know what you really meant. Most of your own answer is not actually about "finding motors", or "correct terminology." It may well be useful for you personally, but IMO it's a poor answer in the context of what the SE site is for. $\endgroup$ – alephzero Oct 16 '16 at 17:12

In the case of industrial type AC motors it is generally not that difficult to just change the bearings.

In terms of building from scratch you can get rotor and stator assemblies as replacement parts. The difficulty is that the housing is usually an aluminium casting which is made to fit the rotor and stator and is usually made in two pieces which also incorporates the bearing housing so if you want a significantly different bearing housing you have a fairly major fabrication and machining job on your hands.

Having said that, while it may be desirable to replace a generic bearing with a branded one this is usually a like for like swap as you will presumably just want better quality rather than a radically different size and is not usually a hugely difficult task on larger AC motors such as you find on lathes etc.

I say AC because they are usually capable of fairly easy disassembly but the same applies to larger DC motors as well. The smaller ones tend to be a bit more difficult to get into and are less likely to have separate spares readily available.


In addition to Chris Johns' answer I have done further research to answer this question and have discovered the following:

(1) In general, there are no special customizable motors made; motors are made in such a way that they can be taken apart with the right tools, so every motor more or less is customizable with the right tools.

(2) Some manufacturers sell "modifiable" motors that allow a buyer to alter the way the motor is configured to a limited degree, but usually you must be making a bulk order to take advantage of this. Note that such "modifiable" motors only allow the customer to switch out components for fixed alternatives that the motor manufacturer has pre-determined.

(3) To change the bearings on a motor requires equipment such as bearing pullers and snap ring pliers. It may also require an arbor press for the larger motors or even a hydraulic press for really big motors.

(4) In many cases you can get different bearings with the same form factor, so you can change your bearings to a different type with no further modification. For example, you could change ball bearings with roller bearings.

(5) If your wanted bearing is in a different form factor, you may need to modify or fabricate the plate that holds the bearing to the frame, or alternatively create an adapter that fits to the existing plate.

(6) If the motor does not have enough room to accommodate your bearing, you can remove the motor's bearings entirely and place your bearings outside the frame. This will probably require removing the motor's bells, the end caps. Your subframes for holding your custom bearings must be aligned so that the spacing between the rotor and stator is exactly equal all around. (If you can improve this spacing, you may be able to improve the performance of the motor over the factory build.) You will probably need a new, longer shaft to place bearings external to the existing frame.

(7) The shaft of nearly all motors is joined to the rotor with a simple interference fit, or a force fit in the case of very small motors. To remove the shaft warm the rotor to approximately 200F using a heating strip or other mechanism and cool the shaft using freeze spray, a cooling jacket, dry ice, or some similar mechanism. The shaft should now be removable with an arbor press. You can try to force the shaft out cold with a 10 ton hydraulic press, but this risks damaging the rotor, so using a thermal differential is recommended. A new shaft can be inserted into the motor by the same method.


Not the answer you're looking for? Browse other questions tagged or ask your own question.