Re: [CAD_CAM_EDM_DRO] vfd

Jon is that part of the reason why VFD's cause so much noise that even
goes out into the supply line?
Sven Peter

Jon Elson wrote:

>
> tom mazz wrote:
>
> > Hugh,
> >
> > The VFDs do rectify input voltage to DC. The input can be single or 3
> > phase. They then use a 3-phase bridge inverter to create a new 3 phase AC
> > with varying voltage and frequency. The inverter uses pwm and the waveform
> > is filtered to a smooth AC voltage.
>
> Most VFDs do NOT filter the output waveform in any way. They just have
> the power transistors connected straight to the output, usually with current
> sensors on 2 of the lines. This is hard on the motor windings, as a lot of
> voltage stress (400 V for a 230 V system, 800 V for a 440 V system)
> is placed on the outermost few turns of wire.
>
> Jon
>
> Addresses:
> FAQ: http://www.ktmarketing.com/faq.html
> FILES: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/files/
>
> OFF Topic POSTS: General Machining
> http://www.metalworking.com/news_servers.html
> http://www.metalworking.com/news_servers.html
>
> Post messages: CAD_CAM_EDM_DRO@yahoogroups.com
> Subscribe: CAD_CAM_EDM_DRO-subscribe@yahoogroups.com
> Unsubscribe: CAD_CAM_EDM_DRO-unsubscribe@yahoogroups.com
> List owner: CAD_CAM_EDM_DRO-owner@yahoogroups.com, wanliker@...
> Moderator: jmelson@... timg@... [Moderator]
> URL to this page: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO
> bill,
> List Mom
> List Owner
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/