Category: TMEIC

Introduction to TMEIC

A Global network

TMEIC is built on a proud heritage in the industrial automation,

control and drive systems business.  TMEIC’s global business

employs more than 2.200 employees, with sales exceeding $2.4

billion, and specializes in Metals, Oil & Gas, Material Handling,

Power Generation, Cement, Mining, Paper and other industrial

markets.

TMEIC Corporation, headquartered in Roanoke, Virginia, designs,

develops and engineers advanced automation/ variable

frequency drive systems, motors and generators.

Typical Drive Applications in the Power Plant

Variable frequency drives are used to control the speed of fans,

pumps, and mills in power plants.  VFDs are also used to smoothly

start large motors, synchronize, and connect them across the line.

The following seven pages describe four typical applications and

present the reasons why electric drives were chosen.

These selected drive applications are:

• Induced and forced draft fans

• Cooling tower fans and pumps

• Boiler feed pumps

• Service water pumps

• Boiler environmental control pumps/fans

Salient Pole Synchronous Motors

• Ideal for hot strip mills, roughing and finishing stands

• Excellent torque and superior efficiency

• Unit power factor and easy controllability

Squirrel Cage Rotor Motors

• Designed for reels and medium-power stands

• Strong performance at ultra-low speeds

• Constant power across the weakening range

Built to NEMA MG1 and JEM 1157 standards

Shared Benefits

• High efficiency and rugged design

• Minimal maintenance requirements

• Fast, responsive control

• Exceptional acceleration and deceleration

• Flexible performance in harsh environments

Motors for Metal Rolling Mills Features and Benefits

Design Feature

• High strength coil head bracing and connections will withstand magnetic

forces under frequent reversing direction of rotation.

• On squirrel cage motors, an optimal brazing between rotor bars and

end rings will permit the motor to withstand the repeated acceleration,

deceleration and reversal of rotation that is typical in this steel processing.

• Detailed analysis of the electromagnetic field patterns and ventilating

airflows yields an optimized motor design with maximum cooling and

efficiency.

• Application of TMEIC vacuum pressure insulation (VPI) system and

very large autoclave can process any size of stator.

• Static and dynamic strength analysis of stator, frame, rotor, shaft and 

bearings.

• Selection of appropriate forged steel shaft with high tensile strength.

Customer Benefit

• High reliability and longevity with no unplanned production interruption.

• Lower energy expenditure.

• High reliability and longevity with no unplanned production interruption.

• High strength of insulation required for special operating duty and steel

mill environment will ensure long operating life.

• Greater mechanical strength to sustain the multi-directional forces, 

vibrations and electro-magnetic forces ensure continuous operations.

AC adjustable speed motor drive systems are the preferred technology for

new rolling mill installations and modernization projects.

Precision Power for Demanding Steel Applications

TMEIC provides advanced AC adjustable speed motor drive systems tailored

for both new rolling mill installations and modernization projects. Two motor

types meet the range of rolling mill demands: salient pole synchronous motors

deliver high torque and power for roughing and finishing stands with excellent

control and efficiency, while squirrel cage rotor motors serve medium power

needs like reels and auxiliary stands with rugged construction and precise

low-speed torque. Both motor types are engineered for superior efficiency,

reduced maintenance, and reliable performance under extreme rolling conditions.

Squirrel Cage Rotor Motors

• Designed for reels and medium-power stands

• Strong performance at ultra-low speeds

• Constant power across the weakening range

Built to NEMA MG1 and JEM 1157 standards

Shared Benefits

• High efficiency and rugged design

• Minimal maintenance requirements

• Fast, responsive control

• Exceptional acceleration and deceleration

• Flexible performance in harsh environments

The high-speed switching coupled with the three- level power bridge design

delivers a smooth sine wave to the motor and power system.

Bringing Reliable Control To System Applications

High-power, precision-controlled processes are ideally suited for the TMdrive-70e2

with its efficient high current IEGT power devices and control cards common to

the drive family. Flexible arrangement of converter, inverter and cooling units

allows for maximum power density, resulting in minimum floor space, and

installation cost.

Coordinated drive systems are an integral part of numerous manufacturing processes

in the metals industry. TMdrive system drives address all of these applications with

a robust control platform and a common Microsoft Windows based tool. The tool

supports local and remote connectivity, and is an invaluable asset for system and

process analysis. Due to its high reliability, simplicity of design and high efficiency,

the TMdrive-70e2 is perfect for compressor, fan and pumping applications.

It provides accurate speed control and high efficiency while eliminating

the need for high maintenance mechanical flow control devices. The TMdrive-70e2

is also well suited for applications like grinding mills and mine hoists, where high

overloads and impacts are a part of everyday operations.

Features

•  Low Voltage Gate Drive Given that the IEGT is a MOS structure, it can

be gated (turned on/off) with ±15 V

•  Minimal Snubber Circuitry With the high dV/dt capability of the IEGT,

there is only need for a small dc clamp snubber circuit.

•  High-Speed Switching The IEGT is switched at a rate of 500 Hz in this

application.

Benefits

•  High Efficiency and Small Size

A very compact phase leg assembly is achieved with:

• A reduction in snubber circuitry

• Integral forward diodes

• Integral clamp diodes

•  Higher Performance

The reduction in snubber circuitry allows a higher chopping frequency,

lowering the torque ripple applied to the motor and harmonics fed back

into the power system.

•  Motor and Power System Friendly

The TMdrive-70e2 is a new version of the popular TMdrive-70.

The drive offers 4kV class output, and is suitable for induction or

synchronous motors. The drive features:

•  Smaller size

•  Lower weight

•  Additional safety features

The new drive provides the same excellent benefits as the original:

• High reliability

• Regenerative converter

• Simple configuration and maintenance

• High energy efficiency and low cost of ownership

System Applications for the TMdrive-70e2 include:

• Main drives for hot strip steel mills

• Main drives for Cold Mills

• High power drives for compressors, fans, pumps, grinders and mine hoists

IEGT Technology Dramatically Lowers Cost of Ownership

The Injection Enhanced Gate Transistor (IEGT) is a breakthrough

in power switch technology, providing lower cost of ownership.

The high-speed switching coupled with the three- level power bridge design

delivers a smooth sine wave to the motor and power system.

Bringing Reliable Control To System Applications

High-power, precision-controlled processes are ideally suited for the TMdrive-70e2

with its efficient high current IEGT power devices and control cards common to

the drive family. Flexible arrangement of converter, inverter and cooling units

allows for maximum power density, resulting in minimum floor space, and

installation cost.

Coordinated drive systems are an integral part of numerous manufacturing processes

in the metals industry. TMdrive system drives address all of these applications with

a robust control platform and a common Microsoft Windows based tool. The tool

supports local and remote connectivity, and is an invaluable asset for system and

process analysis. Due to its high reliability, simplicity of design and high efficiency,

the TMdrive-70e2 is perfect for compressor, fan and pumping applications.

It provides accurate speed control and high efficiency while eliminating

the need for high maintenance mechanical flow control devices. The TMdrive-70e2

is also well suited for applications like grinding mills and mine hoists, where high

overloads and impacts are a part of everyday operations.

IEGT Technology Dramatically Lowers Cost of Ownership

The Injection Enhanced Gate Transistor (IEGT) is a breakthrough

in power switch technology, providing lower cost of ownership.

Features

•  Low Voltage Gate Drive Given that the IEGT is a MOS structure, it can

be gated (turned on/off) with ±15 V

•  Minimal Snubber Circuitry With the high dV/dt capability of the IEGT,

there is only need for a small dc clamp snubber circuit.

•  High-Speed Switching The IEGT is switched at a rate of 500 Hz in this

application.

Benefits

•  High Efficiency and Small Size

A very compact phase leg assembly is achieved with:

• A reduction in snubber circuitry

• Integral forward diodes

• Integral clamp diodes

•  Higher Performance

The TMdrive-70e2 is a new version of the popular TMdrive-70.

The drive offers 4kV class output, and is suitable for induction or

synchronous motors. The drive features:

•  Smaller size

•  Lower weight

•  Additional safety features

The new drive provides the same excellent benefits as the original:

• High reliability

• Regenerative converter

• Simple configuration and maintenance

• High energy efficiency and low cost of ownership

System Applications for the TMdrive-70e2 include:

• Main drives for hot strip steel mills

• Main drives for Cold Mills

• High power drives for compressors, fans, pumps, grinders and mine hoists