Re: VFD question

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Brian Botton <bbotton@a...>
wrote:

>
> > > VFDs *MUST* be permanently wired to a motor. If you turn one
> > > on without a motor you will probably damage something.
> >
> > Not true. Most if not all drives will do just fine if you run
> > them with no motor connected.
>
> Well, my manuls very explicity state never turn it on, much less
> press the run button, without a motor wired in. If your manual
> explicitly says this is okay, then I stand corrected. The 3 or 4
> different vendor's manuals I've looked at say always keep a motor
> connected.
> My lathe has a 5hp motor, which means a big, expensive VFD. I

spent

> close to $700 for one with the needed capacity. I want that thing to
> last forever and I'm not going to risk damaging it.
>
> Brian

No you can switch then on, ie apply power to the VFD you just can't
press Start.
The reason for the switch on allowance is so that you can pre program
one without it being on the machine.
What is a NO NO is applying load ie start when no load is there or
switching that load either between motors or windings ie. reverse
whilst the invertor is in power mode.

I can DEFINITLY say this applies to Fugi, Mitsubitshi, IMO, Yaskawa,
Westinghouse, Baldor, Alan Bradley and Telemechanique.
These are the only ones I have dealt with and have had personally
read the manuals.
As may of these makes are badged up versions of others I can't see
there being any exceptions, They all follow the same operating
principle.

The latest type of VFD we are using at the moment, the IMO VSX series
allows you to download all the parameters into the VD via serial
cable from a laptop. As our machines are all identical this save
hours of programming but it still requires the VFD to be switch on,
on the bench.

John S.