can any one help me on AC drives?

Answer 1

"A good AC drive technician understands the operation of the variable speed drive and the functions of its components.
An outstanding AC drive technician also understands the effects of the load on the drive and the effects of the drive on the load."
...James Shumberg

Exactly what is an AC drive? The word "drive" is used loosely in the industry. It seems that people involved primarily in the world of gear boxes and pulleys refer to any collection of mechanical and electro-mechanical components, which when connected together will move a load, as a "drive". When speaking to these people, an AC drive may be considered by them as the variable frequency inverter and motor combination. It may even include the motor's pulley - I am not sure.

People in the electrical field and electrical suppliers usually refer to a variable frequency inverter unit alone, or an SCR power module alone (when discussing DC drives) as the "drive" and the motor as the "motor".

Manufacturers of variable frequency drives (VFD) used to refer to the drive as just that, a "variable frequency drive". More manufacturers are referring to their drive as an "adjustable speed AC drive". To make matters worse when a motor is included in the package it may be referred to as an "adjustable speed AC drive system".

A variable frequency drive is an adjustable speed drive. Adjustable speed drives include all types; mechanical and electrical. Now is it clear? Don't worry about it. It's not clear to anyone. As you read on, when I refer to the "drive" I am referring to the variable frequency inverter alone.


A little about AC drives
The main power components of an AC drive, have to be able to supply the required level of current and voltage in a form the motor can use. The controls have to be able to provide the user with necessary adjustments such as minimum and maximum speed settings, so that the drive can be adapted to the user's process. Spare parts have to be available and the repair manual has to be readable. It's nice if the drive can shut itself down when detecting either an internal or an external problem. It's also nice if the drive components are all packaged in a single enclosure to aid in installation but that's about it.

The paradox facing drive manufacturers today is that as they make their drives easier to use, the amount of training with which they must provide their users increases. This is because as drives become easier to use they are purchased more and more by people of less and less technical capability. As less technical people get involved in drive purchases the number of misapplications goes way up. I call this phenomenon the "dumb trap". (When manufactures discover this phenomenon they simultaneously discover how dumb they've been. Some have not yet discovered it.)

Ambiguous Motor Theory
The real action in an AC variable frequency drive system is in the motor. This is really where it all happens.
To be an AC drive application Wizard (which is several levels higher then Guru) one must understand how motors use electric power. It is essential. I cannot emphasize the importance of this.

All loads moved by electric motors are really moved by magnetism. The purpose of every component in a motor is to help harness, control, and use magnetic force. When applying an AC drive system it helps to remember you are actually applying magnets to move a load. To move a load fast does not require more magnets, you just move the magnets fast. To move a heavier load or to decrease acceleration time (accelerate faster) more magnets (more torque) are needed. This is the basis for all motor applications.

Answer 2

The 'real ability' value mark downs would be in accordance with ability ingredient. The section-controlled DC stress would have a poor ability ingredient at decrease speeds, drawing near an very almost perfect ability ingredient at finished velocity. The V*A used interior the motor isn't that plenty different. The DC motor demands a magnetizing container to be energized (different than PM automobiles), as does the AC. The AC magnetizing contemporary is extra complicated to make certain, yet is calculated by using larger end drives, such which you will discover the 'loss' or 'overhead' of only turning the shaft with out load.

Answer 3

What kind of help you want? You can e-mail me. Be specific.