INDUCTION MOTORS AND THEIR USES
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Joined: Sep 2010
14-10-2010, 11:56 AM
ABB REPORT.doc (Size: 226 KB / Downloads: 159)
ABB motors (India) is one of the six manufacturing units of ABB India. The factory is located at Faridabad about 40km from Delhi in the state of Haryana in north central part of India. The technical backup is received from ABB Motors in European countries.
• ABB is pioneer to introduce high efficiency (eff 2) motors in India in the year 1991
• ABB was again pioneer to introduce EFF1 motors for frame 315 & 355 in the year 1998
• It is the only motor factory in India to be accredited for IMS (Integrated Management System) combination of ISO 9001 – 2000, ISO 14001 – 1996 & OHSAS 180001 – 1999.
• We are the only company in India to offer complete range of EFF1 (High Efficiency motors) in frame 100 to 355.
• Standard three-phase TEFC (HX & HX+)motors, IS:325
• Standard three-phase SPDP motors, IS:325
• High Efficiency EFF1 Motors ( Frame 100 to 280)
• M2000 motors, (Eff1 Frame 315 to 400)
• Ring frame motors, IS:2972 Part III
• Auxiliary motors for a.c. electric locomotives
• Auxiliary motors for three-phase electric locomotives
• Non-sparking motors type ‘n’, IS:9628
• Increased safety motors type ‘e’, IS:6381
• Roller table motors
• Flame Proof Motors (Frame 112 / 132 are in production, Frame 100 under development, Frame 160 under Certification)
• Crane duty Motors
• Brake Motors (externally mounted)
• Induction Generators
• Windmill Generators
• Motors for frequency converter drive
• Custom built motors
• Type Three-phase squirrel-cage induction motors
• Output 0.18 ... 500 kW; 0.25 ... 675 hp
• Voltage 415 V; 220 ... 660 V
• Frequency 50 Hz; 25 ... 60 Hz
• Duty S1 ... S8 acc. to IS:12824
• Ambient 45oC; 20 ... 70oC
• Altitude up to 1 000 m
• Insulation Class ‘F’/Class ‘H’ (VPI on request)
• Frame HX71- HX280 & M2BA315 - 400
• High Efficiency – ABB motors are engineered for high efficiency for minimum life cycle costs.
• Low noise level – The motors are designed to ensure low noise level.
• Accessories – Space Heaters, thermistors, RTD and BTD’s on request.
• Terminal Box – Terminal Box suitable for both copper and aluminum cables. Terminal box size sufficient for easy termination and maintenance of cable.
• All motors are provided with deep groove ball bearings with C3 clearance for high load capacity.
• Special care taken at the time of order for considering right bearing at the time
of order (e.g. Roller Bearings for belt Application or Insulated bearing for VFD Application).
• Dual mounting holes – Motors are provided with 6 nos. mounting holes instead of 4 nos. as standard practice in the industry. This facilitates easy replacement and easy inventory management.
Active In SP
Joined: Feb 2011
21-02-2011, 11:36 AM
Induction_Motors_Lecture_4.pptx (Size: 1.04 MB / Downloads: 67)
Effect of Rotor Resistance on Torque-Speed Characteristics of Induction Motor
Increasing rotor resistance
• Increases starting torque
• Reduces Starting current
• Increases Slip
• Reduces Motor Efficiency
• Increasing slip reduces converted mechanical power, lowering motor’s efficiency
Variations in Induction Motors Torque-Speed Characteristics
Design Requirements for Induction Motors
1. Higher starting torque
2. Lower slip at normal speed (good efficiency)
3. Lower starting current
How to achieve these goals
1. Higher starting torque is achieved by increasing rotor resistance
2. Lower slip at normal speed is achieved by decreasing rotor resistance
3. Lower starting current is achieved by increasing rotor resistance
“Design requirements are conflicting”
How to Overcome these Conflicting Requirements?
Use a wound rotor motor
◦ Insert resistance in the rotor circuit at startup
Gives higher torque and lower current
◦ Remove the resistance when motor reaches normal speed
Decreases the slip and increases the efficiency
Drawbacks of Wound Rotor Motors
◦ More expensive
◦ Need more maintenance (slip rings, brushes)
◦ Require a more complex automatic control circuit than cage rotor motors
Then what should one do?
Figure out a way to add extra rotor resistance at start and remove it during normal running without slip rings and without operator or control circuit intervention
Desired Motor Characteristics