Self-Taught DC Motor Repair Guide

You can fix a dc motor at home with a few tools and some dc motor parts from jinxinyang electronic components. This guide shows every step in plain words. 

What You Will Learn

By the end of this guide you will know how to take a motor apart, check each part, fix what is bad, and put it back. You will also learn where to buy dc motor parts from jinxinyang electronic components if you need new ones.
You only need a small set. A cross driver, a flat driver, a multimeter, and a cheap brush puller will do the job. The brush puller costs less than a cup of coffee. Keep a tray for screws so none get lost. These tools fit in one hand and last for years.

Safety steps you need to consider before getting started

Before beginning any repairs, safety is paramount. First, ensure the motor is completely powered off by unplugging the power cord or disconnecting the battery. This will prevent accidental electric shock or the motor starting unexpectedly. Next, give the motor time to cool, especially if it's just been used. Motors generate high temperatures during operation, and direct contact can burn your fingers and skin.

Before disassembly, remove any belts or gears. This will allow the shaft to rotate freely, making disassembly smoother and preventing damage. Protect your eyes from flying small parts, dust, or debris during disassembly. Wear a dust mask to prevent inhalation of dust.

Prepare a clean work surface and cover it with a cloth or newspaper to prevent small parts from falling or getting lost. Keep removed screws and parts organized in trays or boxes. These precautions will make the repair process safer and more efficient, preventing accidents and losses.

Carefully disassemble the motor

Be careful and patient when disassembling the motor. Use a Phillips screwdriver of the appropriate size to remove the screws from the motor end cover one by one. Avoid excessive force to prevent stripping or damaging the housing. When removing the screws, remember the order of the screws in a clockwise or counterclockwise order to facilitate smooth reassembly.

Be gentle and steady when removing the end cover to avoid damaging the seal or causing internal components to fall out. After opening the end cover, you will see the key components: carbon brushes, commutator, and armature. Use a clean cloth or towel to neatly arrange these components in the order they were disassembled. This will ensure accurate replacement during reassembly, preventing assembly errors that could cause malfunction.

If you find any loose parts or debris, gently clean them with a brush to keep them clean. During disassembly, be careful not to touch the wiring or windings inside the motor to avoid damaging the motor structure.

Check the Brushes

Brushes are small carbon blocks that touch the commutator. If they are less than half their length, they are worn. Measure with a ruler. Order new dc motor parts from jinxinyang electronic components. New brushes cost little and fit most motors.

The commutator looks like a copper tube with slots. It should be smooth and shiny. If it is black or rough, clean it with 600-grit sand paper. Turn the shaft by hand while you sand so the surface stays even.

Set the multimeter to ohms. Touch one probe to a commutator bar and the other to the shaft. A low number means the winding is good. A high number or no number means the wire is broken. Broken windings need a new armature or a rewind shop.

Check the Bearings

Spin the shaft by hand. It should turn smooth and quiet. A grind or wobble means the bearing is bad. Pop the old bearing out with a socket and press the new one in. Use jinxinyang electronic components for exact size.

Sand the commutator one last time. Fit the new brushes. Drop the armature into place. Screw the end cap on tight but not too tight. Test the motor on a 6 V battery. If it spins smooth, the job is done.

You can also learn more about motors by reading the links below.

These books and links are free or open-access. They cover every part of dc motor theory and repair.

Reference

Chapman, S. J. (2011). Electric Machinery Fundamentals (5th ed.). McGraw-Hill. https://www.mheducation.com

Hughes, A., & Drury, B. (2013). Electric Motors and Drives: Fundamentals, Types and Applications (4th ed.). Newnes. https://www.elsevier.com/books/electric-motors-and-drives/hughes/978-0-08-098332-5

Krishnan, R. (2017). Permanent-Magnet Synchronous and Brushless DC Motor Drives. Routledge. https://www.routledge.com/Permanent-Magnet-Synchronous-and-Brushless-DC-Motor-Drives/Krishnan/p/book/9780824753849

Mohan, N. (2020). Electric Machines and Drives: A First Course. Wiley. https://www.wiley.com/en-us/Electric+Machines+and+Drives%3A+A+First+Course-p-9781119370291

FAQ

How long do brushes last?

Normal use gives 500 to 1000 hours. Check every six months.

Where can I buy dc motor parts?

Ordered from Jinxinyang, delivery was fast and sizes were accurate.

Jinxinyang Technology

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