DC Motors Flashcards
How is DC current different than AC current?
DC current doesn’t change direction,it always moves in the same direction. Direction of flow is determined by the polarity of the source
How do we turn AC power into DC power?
A rectifier
How do we turn DC power into AC power?
Inverters
What are the 2 basic types of DC motors?
- Brush type
- Brushless
What are the 2 types of brush type motors?
- Permanent magnet
- Wound field
What is the rotating portion of a brush type DC motor?
Armature
Windings are attached to a segmented copper cylinder called what?
Commutator
What are the 3 types of wound field DC motors?
- Series wound
- Shunt wound
- Compound
Characteristics of a series wound motor?
Field windings are in series with the armature windings. Provides high starting torque but no speed control.
Characteristics of a shunt wound motor?
Field windings are connected in shunt or parallel with the armature. Most of the time it is fed from 2 separate power sources. Great speed control unless loss of shunt field power. Low starting torque.
What manipulates speed on a DC motor?
Voltage
Characteristics of a compound motor?
They are the best of both (shunt and series wound) speed varies little with load but it can increase torque output when heavily loaded
Biggest difference in brushless DC motors?
Magnets are mounted to the rotor and the windings are in the stator. There is no armature, commutator or brushes
What are some downsides to DC motors?
Motors costs more, so does the power and maintenance
What HP are permanent magnet motors typically available in?
¼ to 5 HP
