Jump to content

EMC and inverters


Recommended Posts

Inverter (VSDs) are great sources of noise and can cause all sorts of problems.

These problems can be reduced by the correct installation practices. I have a few suggestions and perhaps others can add to the list.


  • Use a screened cable between the motor and the drive. Connect the screen to the motor using a screened gland and connect the screen to the drive using a screened gland.

  • If the screened cable has an earth core, connect it to the earth terminal in the motor and in the drive.

  • Connect all input/output control cables via screened cable terminated at the drive and the control end by screened glands.

  • If the drive does not include an input filter, mount the correct filter as close to the input to the drive as possible. Bond the earth of the filter to the chassis of the drive as close as posible.


      Add your rules also.

      Best regards,

Link to comment
Share on other sites

  • 2 months later...

mount the drive as close as possible to the motor have the cable lenght in the supply cable and not the motor cable.


Should screen only one end of signal cables to prevent earth loops.

Link to comment
Share on other sites

And for our North American readers, "screened" means shielded. As of yet, this type of cable is not readily available in the US (although more available in Canada), but if you can find it, that is the best way to go. Look for "tech cable", which is actually a brand name but is being used now generically to describe 3 conductor shielded armored cable.


Anonymous, if you read Marke's post carefully, he meant terminate the earth core conductor at both ends. He had addressed the screen/shield connection by stating that it should be connected at the VFD, which implies only one end, but now that you restated it, that was good clarification.

"He's not dead, he's just pinin' for the fjords!"
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Create New...