TECO Squirrel Cage Induction Motor

• Output: Ranging from 300 kW up to 15,000 kW
• Number of Poles: Available in 2 to 18 Pole configurations (other configuration available upon request)
• Cooling Method: Options include TEAAC (Totally Enclosed Air-to-Air Cooled), TEWAC (Totally Enclosed Water Air Cooled) & TEFC (Totally Enclosed Fan-Cooled).
• Degree of Protection: Ranges from IP54 to IP66
• Frames: Available in sizes ranging from 315 up to 1250
• Ambient Temperature: Design rated for operation at 40°C with acceptance up to 50°C.
• Design Elevation: Suitable for locations up to 1000 meters above sea level.
• Service Factor: Rated at 1.0 @ 40°C ambient.
• Mounting: Complies with IM international standards
• Voltages: Available up to 13,800V
• Insulation Class: Equipped with “F” insulation rated at 155°C with temperature rise limited to ΔT = 80K for enhanced safety
• TECO Westinghouse patented Thermalastic™ Insulation System for all High Voltage designs, superior form wound winding design.
• Duty: Continuous (S1).
• Design: Conforming to “N” design specifications.
• Thermal Protection: Configurable based on customer specifications.
• Bearings: Equipped with Anti-friction Bearings and Oil forced or self-cooled Sleeve Bearings.
• Frame Material: Constructed with Fabricated Steel Heavy Duty Cast Iron Construction or Heavy Duty Fabricated Steel Construction.
• Colour: Customizable based on customer preferences.

• We offer many tailored features to meet your specific needs and requirements as our valued customer.
• Altitude Above 1000m: Available upon request for elevated locations.
• Rotor Material: Choose from aluminium, copper, or brass rotor options depending on the starting torque requirement of the application.
• High Ambient Temperature: Suitable for environments exceeding 40°C.
• Special High Torque designs are available to suit the specific application.
• Special Low Inrush Current designs are available to suit the specific application.
• Base Options: Select from various base configurations, including rail, sliding base, extended feet, rebuilt feet, and anchorage plates.

• Bearing thermometer with gauge with/without contacts

• • Cable Gland Designs: Options for cable gland configurations into the terminal box gland entry size and positioning
  • Insulation Class: Upgrade to Class “H” insulation rated at 180°C.
  • Classified Area Application: Suitable for Ex-n and Ex-p classified areas.
  • Cooling Options: Choose from self-cooled, forced ventilation and air-to-water heat exchanger cooling methods.
  • Current Transformers (CT) for Differential and Integral Protection: Configure for specific protection needs.
  • Encoder: Supply incremental or absolute encoder for precise speed monitoring and speed control feedback.
  • Grounding Brush: Equipped on the drive end shaft for improved earthing of the rotor circuit.
  • Independent Hydraulic Oil Circulation System: Available for forced cooled sleeve bearings.
  • Mounting Options: Includes vertical, horizontal, foot & flange, and NEMA standard mounting configurations.
  • NEMA Standard meeting overseas project requirements
  • Noise Suppression: Installed at the air inlet and outlet for overall reduced noise levels.
  • Non-Rotational Reverse Ratchet: Enhances safety of operation.
  • Multiple Accessory Terminal Boxes: Customized to suit your specific requirements and locations if reversed engineered.
  • Surge Capacitors & Lightning Arrestors: Available for enhanced incoming supply protection to windings.
  • Service Factor: Rated for 1.10, 1.15 or 1.20 for extended performance.
  • Shaft Options: Choose from special dimensions, double shaft ends, tapered shafts, hollow shafts, and specialty steel shafts.
  • Signal Transducer: For monitoring and control purposes.
  • Sleeve Bearing: Available for specific applications.
  • Special Balance: Customized for precise applications.
  • Special Bearings: To accommodate axial or radial thrust.
  • Special Balance: Customized for precise applications.

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TECO Large Motors and Drives Brochure

IOM-TECO-MHV-SCIM-3A057H873E-Rev.05

What is a squirrel cage induction motor?

It is a three-phase AC induction motor whose rotor is a cage of conductor bars that are short-circuited by end rings. The stator induces a rotating magnetic field to the rotor, the rotor has no brushes, no slip rings and no external connection. TECO manufactures the medium and high voltage version on this page from 300 kW to 15,000 kW at voltages up to 13,800 V, for continuous duty (S1).

What is the difference between a squirrel cage and a slip ring motor?

The difference is in the rotor design and construction. A squirrel cage rotor has bars short-circuited by end rings with no external connection. A slip ring motor, also called a wound rotor induction motor, has a wound rotor connected through slip rings and brushes that connects to an external resistance that limits starting current and controls starting torque and starting time. The brush gear wears and requires regular inspection and maintaining. A squirrel cage motor on a variable speed drive gets its controlled start from the drive: the drive smooths the inrush current during starting and removes abrupt starts and stops.

What are the advantages of a squirrel cage motor?

The rotor has no brushes, slip rings or external connections, so there is nothing on the rotor to inspect or wear apart from the bearings, and as such the motor suits long continuous duty. The same construction also suits hazardous areas: TECO TEFC and TEAAC squirrel cage motors are built for safe and hazardous area installation, with oversized anti-friction or sleeve bearings. On a variable speed drive the motor also gives a controlled start and speed control without any change to the rotor design.

Can a squirrel cage motor run on a variable speed drive?

Yes. TECO medium and high voltage squirrel cage motors are designed for use on variable speed drives, and the TECO MV510 medium voltage drive is built specifically for them: its multilevel H-bridge output waveform is near-sinusoidal, which keeps motor harmonics and torque pulsation low, with virtually no cable length limitation and no external filter required. The MV510 can also start several motors in turn and transfer each one synchronously to the network supply. TECO low voltage squirrel cage motors carry inverter-rated insulation as standard.

How does a squirrel cage induction motor work?

The three-phase stator winding, when energised, produces a magnetic field, which induces a rotating magnetic field to the short-circuited rotor bars; the interaction between the stator magnetic field and the rotor circuit in turn rotates the rotor assembly, a little below the synchronous speed of the field. No power is fed to the rotor, which is why there are no brushes or slip rings. Synchronous speed is fixed by the supply frequency and the number of poles, and TECO builds the range from 2 Pole high-speed machines to slow-speed high-polarity motors.

Why is it called a squirrel cage motor?

The name comes from the rotor: the conductor bars joined by an end ring at each end, seen removed from the laminated iron core, looks like the cylindrical exercise wheel once sold for pet squirrels; hence, squirrel cage. The name describes the rotor only; the stator is the same as in any other three-phase induction motor.