Articles

Resurrecting an Old Technology VSR Motors

A 170 year old electrical technology, called variable switched reluctance (VSR) motors was resurrected in the 1980s with the advent of electronic controllers. The Texas based Le Tiurneau.inc has developed a wheeled front end loader for mining work which use large horsepower VSR motors for its wheel drives. Basically, a VSR motor comprises a rotor and a stator with a coil winding in the stator. The rotor, which consists of a laminated permeable material with teeth, is a passive device with no coil winding or permanent magnets.The stator typically consists of slots containing a series of coil winding, the energization of which is electronically switched to generate a moving field.

When one stator coil is set on, a magnetic flux path is generated around the coil and the rotor. The rotor experiences a torque and is moved in the line with the energized coils, minimizing the flux path. with the approximate switching and energization of the stator coils, the rotor can be encouraged to rotate at any desired torque and speed.VSR Motors offers the following advantages: Since there are no brushes ringing, there is no requirement of commutator maintenance. the motor is more robust since there are no coils or moving parts.

A VSR motor can maintain higher torque and efficiency over broader speed ranges than is possible with other advanced variable speed systems. In addition, as the commutation can be accurately controlled with respect to the rotor angle, the motor will operate at its predicted high efficiency. With VSR technology it is possible to design a low cost motor with over 90% system efficiency and variable speed.VSR motors can be programmed to precisely match the loads the serve, and their simple rugged construction has no expensive magnets or squirrel cages like the induction motor. VSR motors are smaller than DC motors.

VSR motor is inherently resistant to overload and immune to single point failure. They have a high level of fault tolerance and are immune to switching faults. According t a spokesman of Le Tourneau, While the initial cost of SR motor and control is a little more expensive than standard DC system, in the failure, there may be little or no difference in the manufacturing costs due to decreasing prices of electronic components.

VSR motors are not without their drawbacks, however. The most significant downside is the acoustic noise and the large vibration caused by the motor's high pulsating magnetic flux. Another limitation is torque ripple. But while these drawbacks have an effect in small horsepower VSR motors, they are of no significance in large horsepower traction motors.

.Praise is the Professor and Head of the Dept of Information Technology of Calicut University. with more than 25 years of Professional Experience in University of Calicut.

By: Praise Paul

Technical Training

Holographic Church with God Like Images - Do you ever get up on Sunday Morning and just dread going to Church and listening to more of the same? You feel as if you have your own personal relationship with Jesus yet, somehow sitting in a room with 100?s if not 1000?s of others chanting and.

th Birthday Gift Experiences - When someone you know turns 40, you will want to make certain that their special day is remembered.

What you need to know about silver and silver jewelry - Silver is perhaps the most readily available and affordable precious metals on the planet.

Strategic Issues for Successful BC ECommerce - Developing shopping cart software needs dip technical knowledge of database management along with accounts and billing practice and their applications apart from network security.

Inflatable Pancake For VSTOL Aircraft - Due to the need to take of and land aircraft in smaller spaces and also to provide more safety to air travel new technologies will be needed.

more...