Inspecting / Replacing your Motor Brushes

The brushes on A1 Elite with Stitchrite SR machines start off as sticks of carbon, 16mm long and of 6mm square cross-section – the same material as used for pencil leads. Their function is to conduct the electricity from the wires to the rotor of the motor. Carbon is used not just for its conductivity but also because it is softer than the copper it must run on and it is also a lubricant in its own right. It WILL wear down with use, however. When one of the brushes gets to be 8mm long it is time to replace both of them. It is recommended by A1 Quilting Machines to CHECK your brushes after 1500 hours of machine usage. Because one will wear faster than the other you may decide you can do another 1000 hours just by swapping them over. At the very least you will get an appreciation of how fast your brushes are wearing. If you see black dust collecting under your motor or start to have the motor ‘backfiring’ then please check immediately – as this is a clear indication that your motor brushes are wearing too much.

To compensate for the wear the brushes are mounted on springs which keep the carbon stick pushed onto the copper rotor. In all old motors (pre Platinum version)Β  the brush unit resembles a jack-in-a-box when you get it out and more particularly when you try to get it back in again. You can easily access both brushes that are located on each side of the motor opposite each other.

Remove the slot-headed black plastic screw-in cap that retains the jack-in-a-box spring-thing-with-the-carbon-brush-attached. Unscrew this black plastic cap to access the brush assembly. The worse case will be on the left-hand side of the machine so you might like to start there. If this brush is, say, 12mm long you will get good mileage by swapping it with the right-side brush which will be maybe 14mm long. If the left brush is 8mm or less contact us for a new set. At $24 a pair (incl GST) it is CHEAP INSURANCE.

Align the curve at the end of the carbon brush with the long axis of the motor, push the jack back in the box with your finger and then insert a very small screwdriver under your fingertip, from the side, to take over the holding-in duties. Now you can position the black-plastic-cap-and the screwdriver over the hole and withdraw your tiny screwdriver. Turn carefully in a clockwise direction until you feel the threads meshing.

WHY should you do this? IF you are the lucky sort, when your brushes become too short to make contact with the rotor, your machine will just slow down and eventually stop – usually noticeable over a day or so. Replace the brushes and you’re away again. HOWEVER, it is possible to permanently damage your motor if symptoms are ignored for too long. It’s not worth NOT doing this job.