# need some enlightenment



## ohiosparky99 (Nov 12, 2009)

recently started terminating VFD cabinet that feeds about 20 motors on conveyor line, have only hooked up a few large VFD cabinets like this, just curious but i noticed that the feed comesinto the panel, from there to the overload,from there to a small reactor, from there to the VFD and then out to the motor, my question is what exactly is the reactor doing, what is its porpuse and how does it work?? its like this for all 20 motors, all motors have separate OL's, seperate reactors. and separate VFD's if this helps


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## ampman (Apr 2, 2009)

do you mean rectifier if not the only reactors i know about are in nuke plants or subs


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## ohiosparky99 (Nov 12, 2009)

no, not rectifiers, they definately say reactor, sorta look like a transformer


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## RIVETER (Sep 26, 2009)

I believe they would be a surge or spike arrester. We have them but I've never work on one.


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## ampman (Apr 2, 2009)

ohiosparky99 said:


> no, not rectifiers, they definately say reactor, sorta look like a transformer


 can you post a pic.


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## RIVETER (Sep 26, 2009)

I went to another area of the plant and drug some drawings out. The reactors were in series with the phases so they appear to be there to help prevent current surges. They are mounted external to the panel; I don't know if it was for heat considerations or space. Anyway, I'd say they ARE surge suppressors.
You can see that if the reactor is in series with the phases that a sharp increase in current would cause the fields of the reactor to increase and oppose that current much as the CEMF opposes current when a motor first starts up.


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## gardiner (Sep 25, 2007)

The reactors are usually a type of coil to build reactence in an electronic circuit


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## mattsilkwood (Sep 21, 2008)

Here you go.
http://ecmweb.com/mag/electric_line_reactors_vfds/


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## Lz_69 (Nov 1, 2007)

The VFD converts the line ac to dc via a rectifier circuit but like all rectifier circuits there is a ripple current so they use either capacitors or inductors(aka. reactor) to smooth the ripple out. It make a more stable dc current to invert into the variable ac output.


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## RIVETER (Sep 26, 2009)

The reactors I've seen typically are ahead of the VFD>


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## ACDC (Apr 15, 2010)

Hi,
When you add a line reactor it reduces the current(A) harmonic content.
This will lead to reduced rms input current, reduced supply voltage distortion, better input power factor and increased life of the DC link capacitors.

Actually just a filter!


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## John Valdes (May 17, 2007)

Everything you need to know was on the page right before this one.
http://www.electriciantalk.com/f28/line-reactor-load-reactor-12787/


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## ohiosparky99 (Nov 12, 2009)

Thanks for helping to clear that up, so is it safe to say that the reactor should probably be the first piece of equipment after the OCPD, ahead of the VFD and the Motor to " clean up and filter" the voltage for the entire circuit and not just the motor??

Thanks for the help


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## ACDC (Apr 15, 2010)

ohiosparky99 said:


> Thanks for helping to clear that up, so is it safe to say that the reactor should probably be the first piece of equipment after the OCPD, ahead of the VFD and the Motor to " clean up and filter" the voltage for the entire circuit and not just the motor??
> 
> Thanks for the help


you're welcome!
...just a bit of advice, if the vsd manual is available take the time to go through it. It will explain most of what you need to know.:thumbup:


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## cdnelectrician (Mar 14, 2008)

mattsilkwood said:


> Here you go.
> http://ecmweb.com/mag/electric_line_reactors_vfds/


 
Good article!!!:thumbsup:


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