Continuous Regenerative braking of a downhill conveyor

[Fullelove]

How can I use regenerative braking continuously. I have a stacking conveyor that that wil be running down hill and then gradullay luffing up as we fill a dam with concrete.

I want to use regenerative braking continually (24hrs a day) for the first 6 months as the weight of the load will drive the conveyor down. Speed control isn't critical as the whole system will be working at one speed but I want to control the speed of the luffing conveyor to match the other conveyors

After 6 months the conveyor will be driven as normal for a total of 2 years. Hence the option must also be cheap.

It is my understanding that standard drives do not like being driven in this mode of operation on a continuous basis. Please advise

 

[mdonner]

I suggest using a VSD in conjunction with an embedded/external regenerative breaking system.
This may not be the cheapest to install, but I believe will have the lowest overall price (design, install, maintain, control, operate).

Such a unit works in a cement factory for several years now, 24/7, controlling a several 100's HP blower motor ramping up and down all the time to keep a control set point.

 

[mdonner]

I failed to mention an important aspect:
The regeneration system is connected to mains power lines to supply the network when regenerating.
If mains supply disappears for any reason, you will have NO BRAKING!!! You will need powerfull emergency braking/holding drum to kick in on mains failure.

 

[Fullelove]

Were the blower motors operating in continuous regeneration mode 24/7. The application is not a short cycle braking. Wil this make a difference.

 

[mdonner]

No difference. No duty cycle limitations.
Check with Reliance Electric / Allen Bradley (under Rockwell Automation) local rep./dealer

 

[jraef]

Look up Bonitron on the web. They make stand-alone regenerative brake systems for exactly your type of application. They can be retrofit onto and standard VFD. But heed mdonner's advice. When you loose power, the load can run away on you. Back it up with an adequate emergency stopping brake system.

Quando Omni Flunkus Moritati

 

[RadarRay]

I believe Eurotherm has a drive which when you load the correct software becomes a regenerative front end. So it will work either way. This is the same as Mdonners description because you require two IGBT bridges to do it if you are going AC.

If you wanted to go DC any old regenerative DC drive would be able to do this. Only problem is, the plant power factor takes a hit.