Hey Atroz, hey Brian @hortoni, hey Andy @AndyP, hey all,
you can make the spindle cable longer than 6 m and it is often the case in industry, but the longer you make it, the thicker it has to be as the voltage drop increases with the length because of higher resistance, and the bigger the cross-section area of the individual wire, the less its resistance. Already the spindle cable I have, which is an industrial type for power chains and it is dimensionated according to formulae used in the industry, is impossible to fit into these flimsy “aviation connectors” used on the cheap chinese spindles (that’s why serious spindles have other connectors). So usually you have rather thin cables when using the cheap chinese equipment, and alone for this reason, making them longer than absolutely necessary is to avoid because it would increase resistance and thereby voltage drop, and they can get hot then.
Besides correct dimensioning of wire strength, in my VFD manual, precautions are recommended on cables lengths above 10 or 20 m. My VFD has a parameter b033 “Motor cable length” that can be adjusted from 2 to 25 m, which takes into accounter higher earth capacitance on longer cables.
Furthermore it says:
The output reactors are then shown with their part No.:
– Source: Omron MX2 User’s manual (PDF)