18:27 Dec 15, 2011 

Umdrehungen pro Minute : confirmé après recherche sur Linguee, pour revolutions per minute.

18:09 Dec 15, 2011 

Umdrehungen pro Minute (tours par minute)
(Google translation of revolutions per minute, I'm not a German speaker)

15:54 Dec 15, 2011 

That's important extra context, and certainly helps explain things!

What have you got for that 'u/m'? Looks like it ought to be 'rpm', but I don't know what the 'u' would stand for in some other source language; then again, it might be nothing to do with the rotational speed, as these are variable speed anyway ;-)

15:44 Dec 15, 2011 

That makes sense now. I think it is a translation from either Danish or German into English.

15:41 Dec 15, 2011 

Ah yes, now that makes much more sense: it certainly would seem then that there might be 2 electronic control units, on for each motor in the unit.

15:32 Dec 15, 2011 

There are actually 2 brushing units on the top, and two brushing units at the bottom. May it be that 2ea refer to 2 motor units, each equipped with variable speed and inverter ?

15:24 Dec 15, 2011 

Well, of course we need more context to be sure, but that is certainly one plausible possibility; however, the punctuation of the source text looks dodgy, so Nicolas really does need to check the accuracy so as to avoid making an error.

It could be a variable speed controller AND an inverter, or as you say, a variable-speed inverter (but the punctuation is wrong for that)

It is also unclear why, in that case, they would have used 'each' — does this ONE motor actually have TWO drive units?! Or is this in fact saying that there are two of them overall? It might be non-native quality EN, and they meant to say '2 off', but it still seems to imply that ONE motor has TWO drives...

15:24 Dec 15, 2011 

Brushing motor bottom 4Kw-1400 u/m – 2 ea- Variable speed, Inverter

15:20 Dec 15, 2011 

...there is a VARIABLE FREQUENCY DRIVE (with an inverter inside) for each of the TWO motors (as specified by the asker). So there are 2 motors, each equipped with a VFD. Does that make sense?

15:14 Dec 15, 2011 

I think you'll find this is probably just referring to some kind of speed control device (variateur?), and as for the '2 ea.', I'm pretty sure it just means 'two of each of the following items:...'