i didn't saw this case study in slide share thats why uploading this vedio

1. SELECTION CRITERIA OF MOTORS
FOR VARIOUS APPLICATIONS
-BY R.PRASANTH

2. What is a motor?
 Device that converts electrical or other energy into mechanical
energy or imparts motion
 Concerned with or involving muscular movement

4. AC Motor:
 The motor that converts alternating current into mechanical power
by using an electromagnetic induction phenomenon.
 Two parts: stator and rotor
 Stator: stationary electrical component
 rotor: rotates the motor shaft
Two types
o Synchronous motor
o Induction motor
Induction motor classified in to two main groups:
 Single-phase induction motors
 Three-phase induction motors

5. Single Phase Motor:
 The main components of a single phase motor are the rotor and
stator winding. The rotor is the rotating part, the stator winding
helps in rotating the rotor.
 The winding has got 2 parts; One main winding and an auxiliary
winding. The auxiliary winding is placed perpendicular to the main
winding. A capacitor is connected to the auxiliary winding.
 uses:
 Mostly used in homes and small businesses

6. Three Phase Motor:
 A 3-phase induction motor has two main parts : a stationary stator and a
revolving rotor
 The operation of a 3-phase motor is based up on the application of
Faraday Law and the Loretz force on a conductor

7. DC Motor:
 It is an electric motor designed to be run from a direct current power source
 Mainly there are two types of DC Motors
 Separately Excited DC Motor
 Self-excited DC Motor
Self-excited motors are further classified as three types:
 Shunt motor
 Series motor
 Compound motor

8. Factors To Consider In Selecting
Electric Motors
 A motor must do three things:
1. Start the equipment load
2. Drive the load once it is started
3. Survive the abuse of the surroundings in which it operate

9. Steps to motor selection:
 Start with two basic parameters
 Speed
 Torque
 Configure motion compass with specific application requirements

10. Type of Power Available
 230-volt motor should not be used if only
115-volt circuits are available
 Three-phase motor cannot be operated on electrical system with only
single-phase service
 Typical Operating Voltages:

11. Size of Motor:
 Rated in Hp
 Refers to the power that it will develop when the motor is turning at
full speed
 “Rules of Thumb” for estimating size needed:
 If equipment can be operated by hand, a 1/4 Hp motor will
usually be adequate
 If gasoline engine is to be replaced by electric motor, an electric
motor approximately 2/3 the Hp rating of the engine will be
adequate
 Replace tractor PTO with an electric motor of approximately the
same Hp

12. Starting Load:
 Selected motor must produce adequate starting torque to start the
load
 Commonly–used motors:
 Split phase
 Capacitor start-induction run
 Capacitor start-capacitor run
 Repulsion start-induction run
 Series or universal
 Shaded pole
 Three-phase
 Capacitor start-induction run & Three-phase are the most common
and produce highest starting torque

13. Speed Requirement:
 Rated at the speed the shaft will turn in revolutions per minute (rpm) when
motor is operating at full speed
 Rpm of motor should be speed needed to operate equipment at proper
speed
Bearing type
 Sleeve bearings
OR
 Anti-friction bearings
 Require less maintenance and can be mounted in any position

14. Base Type:
 Rigid base
 Sliding adjustable base
 Cushion mount
 Reduces vibration & wear
 Determined by application of motor

15. Environment:
 Provide proper protection from surroundings
 Typical motor enclosures:
 Open drip proof
 Splash proof
 Totally enclosed-fan cooled (TEFC)
 Explosion proof
 Totally enclosed-air over (TEAO)
 Totally enclosed-non ventilated (TENV)