Test with a multimeter

DC motor

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Now: Winding resistance: shaft at the start

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Pin 1: Terminal 1 (1) Pin 2: Terminal 2 (2)

Red probe Not connectedBlack probe Not connected

Hold the probe and drag it to the tip of a leg. Tapping works too: first pick the probe, then the leg.

Set the range to Ω (resistance).

Measure step by step

The winding of a brushed DC motor shows a few ohms (about 8 Ω in this guide). As you turn the shaft the value changes slightly because the brushes move onto different commutator segments, but it must not be OL at any position.

Disconnect the motor from the circuit. While the shaft turns, it produces a small voltage at its terminals: turn the shaft slowly by hand while measuring.

  1. 1Winding resistance: shaft at the start
  2. 2Turn the shaft half a turn, measure again
  3. 3Continuity