starter basics. motor principles n dc motors interaction of magnetic fields to convert electrical...

Starter BasicsStarter Basics

Motor PrinciplesMotor Principles DC motors interaction of magnetic fields DC motors interaction of magnetic fields

to convert electrical energy to to convert electrical energy to mechanical energymechanical energy

Current is applied to field and armatureCurrent is applied to field and armature Conductor tends to move from weak Conductor tends to move from weak

magnetic field to strong magnetic field.magnetic field to strong magnetic field. For armature to continue rotating, the For armature to continue rotating, the

current flow must be reversed.current flow must be reversed.

Conductor CurrentConductor Current Conductor has Conductor has

magnetic flux magnetic flux lines around it lines around it

Opposes north Opposes north and south fields and south fields which causes which causes loop of wire to loop of wire to turn.turn.

MagnetMagnet Has north and Has north and

south pole.south pole. Magnetic lines of Magnetic lines of

force move from force move from north to south north to south pole.pole.

Conductor in Conductor in Magnetic FieldMagnetic Field

As current As current travels through travels through conductor and conductor and fields, conductor fields, conductor moves.moves.

Flux lines Flux lines always tend always tend to want to to want to be straightbe straight

Fields act Fields act on each on each otherother

ROTATION OF CONDUCTOR ROTATION OF CONDUCTOR IS IN DIRECTION OF IS IN DIRECTION OF WEAKER FIELD.WEAKER FIELD.

Electromagnetic MotorElectromagnetic Motor

Made of Laminated CoreMade of Laminated Core Solid Steel ShaftSolid Steel Shaft CommutatorCommutator Lap and Wave WoundLap and Wave Wound

Stationary Field WindingsStationary Field Windings

Iron Core & Windings concentrate magnetic fieldIron Core & Windings concentrate magnetic field Fields have north and south pole based on Fields have north and south pole based on

direction windings are wound around pole shoesdirection windings are wound around pole shoes

3 Methods of Connecting 3 Methods of Connecting FieldsFields Series WoundSeries Wound

Maximum torque Maximum torque when startswhen starts

Shunt WoundShunt Wound Used in smaller Used in smaller

motorsmotors Compound Compound

WoundWound Constant speedConstant speed

Page C143

The The powerpower is in the size of the windings, the size of the is in the size of the windings, the size of the windings, the number of turns and how its woundwindings, the number of turns and how its wound

PERMANENT MAGNET PERMANENT MAGNET STARTER MOTORSTARTER MOTOR Has no field circuitHas no field circuit Very light weightVery light weight Usually gear reduction starter motorsUsually gear reduction starter motors Fairly fragileFairly fragile Permanent magnets are stronger than Permanent magnets are stronger than

typical permanent motors (Made of typical permanent motors (Made of boron, neodymium and iron)boron, neodymium and iron)

ANDAND THATS ALL!!THATS ALL!!