Cable Length Restriction for Drives

I am not sure about your question. Neither the dv/dt...?! Anyway,the effect will be minimal, once those devices all have some kind of feedback analysis from the pulses they generate and optimize the pulse response according with the load. or you can buy another cable with larger section to reduce the the voltage drop to a decent value.

this is not really a problem!

What does the VFD manufacturer or your contracted electrical engineer say about moving the drive so far away? These are the individuals that have some official standing at your facility, not us. Having said that, allow me a stab at your problem.

All of the VFD that I am familiar with operate solely in the audio frequency range. This is such a low frequency range that transmission line concerns will not be a problem with a 200M cable length. So considering then a lumped element analysis, the only concerns I have about the wiring between motor and drive is using a heavier gauge wire to minimize the added voltage drop and power loss. I would use a shielded multiconductor cable for the cable run to reduce the interference radiated by this cable. Now many a VFD work in a closed loop mode where an encoder sends back data on the operation of the motor shaft. Depending on desired motor speed and the resolution of the encoder, this could easily become a transmission line problem. But I doubt that most fans systems would worry about this. I'm sure though that the guys at NASA Ames do worry about this.

Seems you hot linked to a site that disallows that

You should be OK if you use shielded cable such as Belden LINK and calculate for voltage drop LINK

If you have to use larger than 4/0, move the VFD closer to the drive.

Cable must be routed in RGS conduit between the VFD and the drive.

Wow, you mean that to make a real recommendation you actually have to know what parts you have. I thought we were here just to absolve managers from consulting a valid authoritative individual.

All kidding aside, GA.

GA

GA.

On smallish drives we have often added about a 3% 3 phase inductor at the drive on the feed to the motor. Works OK for V/Hz appication but not recommended in general for Flux vector control.

The manuals for the VFD will spell out the installation and cables and filters recommended for their drive.

Besides banning AM radio reception in whole Southern India and SERIOUSLY increased losses nothing else to it.

The distance between the VFD terminals and the the Motor terminals should not be too high. Otherwise; the link between the VFD and the Motor; acts a transmission line; and results in transient spike voltages at the motor terminals. The peak of this voltages may reach approximately 2000 V for the motor rated voltage of 415 V AC; when the cable length is belond 100m. Even though the duration of this spike is very less; because it repeats itself at the carier frequency of the pulse width modulation; in the range of kHz; the effect will be destroy the part of the winding; close to the termination. Motor is more likely to fail due to iinsulation failure of the lead cables; slot mouth failure.

I am glad that you brought this issue to the discussion!

This in deed can be a problem... I was assuming that those cables had the necessary impedance adaptation.

but if they not, any way it can be fixed...there are things called filters, and the responsible can design them to "earth" potentially dangerous harmonics!

or so I think...?