VDf Cables

[mad4x4]

Looking for some OEM or Industry guidance, due to mechanical damage some of our drive cables have been compromised. (Document to reference would be great)

Our contractor in a Shipyard have asked if they can SPICE some VDF Cables ( Between Motor and VDF) rather than pull in a new conductor. These are Medium Voltage large KW drives, 100/200KW with long 60~70m runs.]

I guess this request has come as a cost saving request?


Marine Application for ship

 

[JesperMP]

Yes you can.
We have a terminal box where we transition from regular screened cable to highly flexible screened cable.
Anything that changes the impedance slightly will be a source of reflections, i.e. more noise, but we do it and don't have problems with it.

 

[Puddle]

I guess this request has come as a cost saving request?

Time and money I'd imagine. That cable could potentially be 120sqmm, that's got to be what, £50 per meter?
It's going to be a day or two of work for several people to install a full new cable.

 

[JesperMP]

I assumed that the question was for a screened cable between a VFD and a motor.
But now I think that by "VDF" maybe you mean something else.

 

[mad4x4]

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I assumed that the question was for a screened cable between a VFD and a motor.
But now I think that by "VDF" maybe you mean something else.
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No your correct the Cable between the Motor and the Variable Speed Drive

 

[Saffa]

When you take a VFD cable via a motor isolator you do essentially the same thing. You'd use an isolator with VSD glands that keep the screen continuous.

If it was me, and there was space to do so, I would use a ferrous junction box and VSD brush glands. Joint cables internally using crimp connectors.

If there's no space, then joint the normal way. Use a foil wrap to replace the screen, seal overall using thickwall glued heatshrink.