Brushed DC Motor
It is the direct current motor that reverses the direction of the winding current mechanically by means of a commutator and carbon brushes. It is driven with two cables and turns the other way when the polarity of the voltage applied to its terminals changes. This two-terminal structure is directly compatible with DC drivers having an H-bridge output.
As the voltage increases the speed increases, and as the load increases the current increases. Thanks to this linear behaviour, speed can be set without a separate feedback device, simply by changing the average armature voltage. AXI's ST42, KS250 and PT500 modules are also designed for this type of motor; however, speed setting exists only on the KS250 and PT500 side, while the ST42 is for on/off and direction-reversing applications that do not need speed setting.
- Advantage: The driver side is simple; two power cables and an H-bridge are enough, no phase order or rotor position information is required.
- Disadvantage: Brushes and commutator are wearing parts; the commutation spark produces broadband electrical noise.
When making a selection, read three current values together: the no-load current, the rated (continuous) current and the stall current drawn while the rotor is stationary. The driver's continuous current capacity must cover the motor's real current under load, and its peak capacity the start-up surge. The KS250 is listed with 15 A continuous and 45 A peak, and the PT500 with 30 A continuous and 40 A maximum values.
The context in which this term is used: DC motor and driver fault diagnosis matrix