Reactors/Filters

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Cow

Senior Member
Location
Eastern Oregon
Occupation
Electrician
I have a project requiring an EMI/RFI filter to be installed on a 60HP wellpump running off a drive. Is it kosher to use reactors in conjunction with filters?

I previously installed a filter on 125HP wellpump for the same customer, but the reactor was unhooked already(I assume because it went bad?) so that particular pump only had a filter on the line side of the drive. No reactors whatsoever.

This 60HP has reactors on the line and load side of the drive. Does it matter where in the circuit I stick the filter? I was planning to put it after the reactor and before the drive....?

The customer has a machine that reads ear tags on their dairy cows when they're loaded on a carousel. Supposedly when this well and other VFD controlled motors run it causes a lot of misreads with their equipment.

The existing reactors:
http://www.transcoil.com/Products/InputSide/KLR.htm

The filter I'm using:
http://www.transcoil.com/Products/InputSide/KRF.htm
 
Well. I can at least bump you back up the the top.:)

The Line side of the drive is not nearly as noisy as the load side, but it is electrically connected to the rest of your system. The line side is only maintaining a charge on capacitors. There are harmonics, but mainly 5th and 7th which are low frequency and shouldn't effect your barcode scanner. I would bet your larger size drive has a DC link choke that comes with the drive to reduce harmonics. If you are really worried about it a 3-5% line reactor will help to reduce harmonics and noise ever farther.

The load side of the drive is where most of the noise is, from the transistors firing. You might want to consider VFD cable to contain this noise inside an overall shield. If it is a long distance from the drive to the motor, then you might want to consider load side reactors to prevent standing wave.

I don't have any experience with your EMF filter, but I would guess it is overkill. Curious what others say.
 
Its been awhile since I worked on a drive, but as I remember the reactor on the line side protects the drive from junk on the system from other equipment and the reactor on the load side would be smoothing out the waveform going to the motor.

I would be troubleshooting at the tagging machine, a small reactor / filter choke here might be a better location. Checking with a wave form meter to see what the tagging machine is receiving as input would then allow you to know what your enemy is using in the slings and on the tips of the arrows that the tagging machine is receiving. Then load your catapult with the right flaming rock and to have a win.

Damn to many computer games lately, but you should get the idea.

Kurt
 
cow,

I am no expert on reactors use and so I cannot say for sure if use of the line side reactor in series with your EMI filter would be an issue. I believe it would be ok but could conceivably make one or the other less than optimally efficient?
I recommend you check with Transcoil since they make both.

RE: The Filter:
Since you are talking about an EMI filter - they are designed to be on the line side - not the load side.
If you read the brochure on the EMI filter it states that fact.

VF Drives do in fact produce a lot of noise on the line side that can be both conducted and radiated into other equipment and cause interference issues.
The line side EMI filter is often a strict requirement if the equipment must meet certain EMC standards, such as is the requirement for CE marking.
 
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