Lift application using AC Drives(VFD)

This might help...

http://www.joliettech.com/dc_drive_types.htm

http://www05.abb.com/global/scot/scot239.nsf/veritydisplay/046e0b4cdc2fe50ac1257466003a8443/$file/3adw000059.pdf

A lift, when "empty" requires more torque to lower than to raise due to the counter balancing bias on the hoisting ropes.

Consider this when developing the model of operation in your mind.

Hydraulic and screw driven lifts are something else again...

Why are you exploring this mate?

Why are you exploring this mate?

=> I was asked this by a Electrical consultant, and I was not able to give the wright answer.

I am confused because of the counter balancing weight.

Is anybody manufacturing lifts using linear motors?.

I didn't think so....

....but the concept was not totally outside the realm of possibilities. So I checked.

Read all about it here:http://research.sabanciuniv.edu/14074/1/tjee.pdf

I couldn't find any real examples. I didn't look real hard though.

Maybe you can find some.

I believe they are using linear motors on theme park rides. The linear motors move the ride up to the top, where the linear motors stop providing lift. The descent is a free-fall with permanent magnets used to provide the braking action at the bottom. I believe they are also used in roller coasters to provide the lift to the top of the ride.

It's gets more complicated when you consider the changing weight of the hoisting ropes over the car and the counterweight too.

Lift design and maintenance has specific safety considerations and esoteric design considerations. The electrical consultant (friend?) should be consulting a vertical transportation engineer.

It's still a good topic and I'm looking forward to reading the posted responses.....

All academic. Right? We're not gonna read about it in this year's Darwin awards....

There are too many lift applications to give specific answer to the question. As a lift can be made that it only uses one quadrant. Such as those that the motor pumps hydraulic fluid which cylinder does the lifting.

Can you be more specific in your application?

VFDs (variable frequency drives) are the standard now in chairlifts and reversible aerial tramways. These are very similar to elevators. They can easily start with full loads or no load and are reversible. You also have full variable speed control, for "creep" speed when stopping and starting thru full nameplate rpm. They are easily ramped up and down. VFDs also can provide dynamic braking control.

I am getting too many reply here, but except first few reply , other just not seems to be usable.

The application I am talking about is a Lift used in residential buildings, commercial complex which is meant for human being.

Just want to know the quadrant of operation when the lift car is getting up or down and the counter weight down and up.

Then refer to #1.