Reactor and EMC filters

[PaulBr]

Are line reactors and EMC filters placed at the input of VFD serving the same purpose? We are OEM. Machines that we make have incoming 3 phase power - line reactor - EMC filter - VFD (3HP or 5HP Unidrive SP by Control Technique). Most likely we would need to have EMC filter because these machines have CE label. I am wondering if we are able to remove line reactor from this chain.
Any input?

 

[Skogsgurra]

The line reactor is there to improve distortion power factor (not displacement power factor). The EMC filter is there to reduce conducted EMI. Both may be needed, but if you are in a country that doesn't care for some current distortion, you needn't bother. It is all up to the local code.

Unlike a thyristor controller, a frequency inverter doesn't need line reactors to operate safely.

Gunnar Englund

http://www.gke.org

 

[CJCPE]

Yes, as skogsgurra says, reactors reduce the harmonic content of the current drawn by capacitor filtered diode rectifier circuits. EMC filters are designed to reduce higher frequency noise that may be conducted back to the power source.

 

[ScottyUK]

You will find Control Techniques to be a very helpful companies for tech support - quite a refreshing change in this age of call centres staffed by drones. Are you UK based?


----------------------------------

I don't suffer from insanity. I enjoy it...

 

[PaulBr]

We are located in US, Ohio. But we are making machines for North American and European markets.

PaulBr.

 

[ScottyUK]

Not sure what the US end of Control Techniques is like for support, but if you're stuck the UK guys are very good. At least there isn't too big a language barrier.

I agree with Gunnar and CJCPE - unless you have to meet harmonic limitations then you shouldn't need the reactor. Some very large drives need line reactors to reduce the peak current drawn by the rectifier, but not at 5HP.

I do think you may fall foul of the harmonics limitation regs in Europe at this power level. Europe has slowly been tightening the requirements on harmonic-producing loads: check out IEC 61000-3-2 : 2000. I'm not hugely familiar with this standard because it was published after I left the power electonics sector, but it should help you work out what you need in place for the European market.

----------------------------------

I don't suffer from insanity. I enjoy it...

 

[ozmosis]

I would say for the cost of the AC line reactor, I would suggest you keep them in. If you are supplying your machines around N.America and Europe, that's quite a range of supplies your machine will be connecting to and as well as providing a method of reducing the effects of harmonics, the line reactors will provide some protection to the drive's input bridge rectifier in the event you get surges or spikes on the supply. I imagine the last thing you want is problems on your machine in Europe due to a blown rectifier on a 3 hp drive. For reliability, peace of mind etc is this worth shaving off a few dollars?

 

[Marke]

Hello PaulBr

If you are exporting into Europe, you need to ensure that you install the drives in the manner for which they have been tested to gain the CE mark. If the CE testing and certification was done with both the EMC filters and line reactors, then you need to use both in order to comply with the CE certification. If the testing was only done with an EMC filter, then that is all you need to comply.
Note: there a major differences between EMC filters, you need to use the type specified in the documentation.
The AC line reactor can have an influence on the EMC performance, so if it was in place in the original testing, you need to use the correct type.

Some VFDs include internal inductors in the DC circuit. These serve a similar purpose to the AC line reactors in reducing the level of harmonics in the supply (reducing distortion power factor). If there are DC chokes within the drive, the advantages of the AC line reactors are reduced.

Best regards,

Mark Empson

http://www.lmphotonics.com