MotionRebuild shelfUnplug and unscrew

Brushed DC motor

Also called pmDC, permanent magnet DC, toy motor, hobby motor.

Two wires, a commutator, and a permanent-magnet stator. The most reusable motor in household trash, and also the easiest one to mis-voltage.

If you are new to this category

These parts spin, push, or pump. A motor is a machine that turns electricity into turning. Some start turning as soon as you connect a battery. Others look identical and will not move until a small circuit tells them which coil to power next. The label, or the number of wires, is how you tell them apart.

Count the thick wires before you apply power. Two wires usually mean a brushed motor that can run from a battery. Three thick wires usually mean a brushless motor. Keep the board that came with a brushless motor.

A brushed motor

Two wires mean you can try a low, current-limited voltage and it should spin. The case often hides a label. If the only label you can find is on the machine, that voltage is the one to believe, not a hobby guess.

Mains voltage. Line voltage, and the DC bus just after the rectifier, both kill. A disconnected cord is not a discharged supply.
Sheet metal and glass. Case steel, shattered platters, lamp glass, and magnet chips cut deeper than they look.

Specification. The right-hand column is what is typical. The label on the part in your hand wins if they disagree.
What to look for	Usual figure
Wires	2, sometimes 3 with a speed tap
Toy / optical sled	1.5–12 V, tens to a few hundred mA
Automotive blower, window	12 V, several amps, stalled current much higher
Treadmill	Often 90–130 V DC at 10–20 A. Read the plate. Not a 12 V motor.
Life limit	Brushes and the commutator. Sparking and black dust mean they are nearly done.

Volts are electrical pressure, amps are how much current is flowing, and ohms are how hard the part resists that flow. A higher voltage than the part was built for is how salvage parts die on the bench. If a cell in the table says “read the stamp”, that stamp is the whole specification.

What people actually use it for

Robot drive, pump, fan, winch, generator experiment (any brushed DC motor is also a generator)
High-voltage treadmill motors as a lathe or grinder drive only with the original control board

Leave this one when

The brushes are down to nubs, the shaft is bent, or the only label is a treadmill plate and you wanted 12 V.

Buying a new one is the better idea when

A known 12 V gearmotor is cheaper than diagnosing a seized car window motor if you only need one.

How to tell if this one still works

Current-limited supply, brief. It should spin smoothly, not just twitch and smell. Measure no-load current so you know what 'healthy' is for that motor.

Step-by-step on the bench: Identify an unknown motor

Tools you will want: Meter, Current-limited supply, Screwdrivers.

Words on this page

Short meanings, so the rest of the entry is readable if you are not already doing this every weekend.

commutator: The copper drum and brushes inside a brushed motor. They switch the coils as the shaft turns. A healthy two-wire motor of this type runs from a battery.

Where people actually find it

9 notes, most useful first. “Leave it” means the part is in that machine and you should not take it: it is dangerous, worn out, or only useful if you already know that exact repair.

Harvest at a glance
From	Call	How many	How often	Where it sits
Treadmill	Prize	1	always	The front roller.
End-of-life car	Prize	several	usually	Blower, windows, wipers, seats.
Motorized toy	Prize	1–4	always	The gearbox.
CD / DVD / Blu-ray drive	Worth it	1–2	usually	Tray and sometimes the sled.
Inkjet printer	Worth it	1–3	usually	Carriage and paper feed.
Flatbed scanner	Worth it	1	sometimes	Carriage, if it is not a stepper.
DVD or Blu-ray player	Worth it	1	usually	Tray.
Cordless drill	Worth it	1	sometimes	Older tools.
Clock radio or stereo	Bonus	1	sometimes	Cassette decks.

Prize — take this firstTreadmill1 · always
In this particular machine
Often 90–130 V DC, high current. The plate is the spec.
Where to look
The front roller.
How to get it out
Unbolt. Do not assume 12 V.
The condition to expect
Good.
Prize — take this firstEnd-of-life carseveral · usually
In this particular machine
12 V, high current. Wiper motors include a park switch so they know where 'down' is.
Where to look
Blower, windows, wipers, seats.
How to get it out
Unbolt. The blower resistor pack is a separate, hot, useful part.
The condition to expect
Good.
Prize — take this firstMotorized toy1–4 · always
In this particular machine
3–6 V typical. No nameplate.
Where to look
The gearbox.
How to get it out
Measure no-load current.
The condition to expect
Good.
Worth pullingCD / DVD / Blu-ray drive1–2 · usually
In this particular machine
Small 5–12 V motors. Some sleds are steppers instead.
Where to look
Tray and sometimes the sled.
How to get it out
Unplug or desolder the two wires and label them.
The condition to expect
Usually strong. The plastic gear on the tray is the worn part.
Worth pullingInkjet printer1–3 · usually
In this particular machine
Modern inkjets are mostly DC motors with encoders, not steppers.
Where to look
Carriage and paper feed.
How to get it out
Cut the harness with the connector.
The condition to expect
Good.
Worth pullingFlatbed scanner1 · sometimes
In this particular machine
Small, with the encoder.
Where to look
Carriage, if it is not a stepper.
How to get it out
Keep the sensor.
The condition to expect
Good.
Worth pullingDVD or Blu-ray player1 · usually
In this particular machine
Small DC motor.
Where to look
Tray.
How to get it out
With the belt if there is one.
The condition to expect
Good.
Worth pullingCordless drill1 · sometimes
In this particular machine
A stout motor. Brushes are the wear item.
Where to look
Older tools.
How to get it out
Check them.
The condition to expect
Good.
Bonus, if you are already in thereClock radio or stereo1 · sometimes
In this particular machine
Capstan motor.
Where to look
Cassette decks.
How to get it out
The belt is tar. The motor may be fine.
The condition to expect
Belts are scrap.