This idea of using using an AC/DC PSU to run a motor is approximately what we have done. However, to keep it a 3-phase AC drive we use a VFD and being a fluid pumping situation we can vary the pump speed if we wish. The only problem with VFDs is they are horrible for EMC and some companies even offer a line reactor accessory. Apparently there is a new generation of these devices coming out that are much quieter.
-Doug Douglas E Powell Laporte, Colorado USA [email protected] http://www.linkedin.com/in/dougp01 On Thu, Apr 6, 2017 at 1:56 AM, john Allen <[email protected]> wrote: > As Dave said, this is “age old problem” that we also faced at HP Bristol > in the 1980s when we built peripherals that had to operate across the World > – and that meant from 100V 50 & 60Hz in Japan and up to 240V 50Hz for the > UK and a few other places, AND +/- to cope with the relevant required local > tolerances (and so effectively meant +/- 10% *across the board*). This > meant careful selection and testing of PSUs *and of the ratings to be > marked on the end-use products*, but fortunately most of our products did > not have directly mains-powered motors. > > > > In practice, if you have a product that does have such motors then it may > well mean that you need to produce separate models with different motors > for the geographical areas that operate at the extremes of the > voltage/frequency ranges – especially those at the lower end thereof – *or > else change the designs to use DC motors supplied from full > voltage/frequency range-capable PSUs (or, *possibly, use AC motors rated > for the lowest “worst case” voltage/ frequency / tolerance combination, *but > with solid state control systems which ensure that those motors are > operated within that regime regardless of the actual supplied mains > voltages/ frequencies/ tolerances*?). > > > > OTOH, the latter approaches are probably impracticable in most cases for > cost /space /weight / technology reasons , and so that means you need a > “horses for courses” approach. > > > > John E Allen > > W. London, UK > > > > *From:* Nyffenegger, Dave [mailto:[email protected]] > *Sent:* 06 April 2017 00:43 > *To:* [email protected] > *Subject:* Re: [PSES] Voltage Rating vs Voltage Specification > > > > Ha! Age old problem. Just have to explain it as you did. And also for > the end product consumer nameplate I don’t put the +-10% rating on the > plate. Had a major motor manufacturer recently trying to tell me that the > motor they have rated for 230V was OK to run at 208V because it’s good for > 230 +-10%. Had to explain to them that I need it to run at 208V – 10%. > Crickets on that one. > > A previous motor from that manufacturer was rated for something like 208V > @60Hz but 190V @50Hz and sure enough when tested at 208V + 10% @ 50Hz the > windings saturated and drew crazy current. > > > > Likewise have to explain to design engineers that they cannot use a 230V > motor in the product rated at 208V and rate the end product at 208V – 0%. > > > > -Dave > > > > *From:* Doug Powell [mailto:[email protected] <[email protected]>] > *Sent:* Wednesday, April 05, 2017 6:52 PM > *To:* [email protected] > *Subject:* [PSES] Votlage Rating vs Voltage Specificaion > > > > Hi all, > > > > Has anyone found a good way to explain to non-compliance types the > difference between voltage rating and voltage specification? After all > these years I still run into this discussion and have not found a good way > to clear the air. > > > > A classic example is an open frame AC/DC power supply used to produce the > housekeeping voltages within a larger product. In a recent example, the > PSU datasheet stated the voltage input range as 85 to 264 VAC. This is > great and I really like that specification. However, I also had a design > engineer who took those numbers from the datasheet and transcribed them > directly to the rating label of his product. As a result the agency > engineer wanted to apply the ±10% rule to the rating label voltage and > the rating tests were then 76.5 to 290.4 VAC (this was not an ITE > product). Note: a little quick math shows that the 264 VAC upper limit of > the PSU is actually a result of 240 V plus 10%. > > > > All this seems obvious to me but apparently not to everyone ... and maybe > it's me who is just a few sandwiches short of a picnic. > > > > I would be grateful to hear any experiences where explanations were > successful and lasting. > > > > > > -- > > > > Douglas E Powell > > [email protected] > http://www.linkedin.com/in/dougp01 > > - > ---------------------------------------------------------------- > > This message is from the IEEE Product Safety Engineering Society emc-pstc > discussion list. To post a message to the list, send your e-mail to < > [email protected]> > > All emc-pstc postings are archived and searchable on the web at: > http://www.ieee-pses.org/emc-pstc.html > > Attachments are not permitted but the IEEE PSES Online Communities site at > http://product-compliance.oc.ieee.org/ can be used for graphics (in > well-used formats), large files, etc. > > Website: http://www.ieee-pses.org/ > Instructions: http://www.ieee-pses.org/list.html (including how to > unsubscribe) <http://www.ieee-pses.org/list.html> > List rules: http://www.ieee-pses.org/listrules.html > > For help, send mail to the list administrators: > Scott Douglas <[email protected]> > Mike Cantwell <[email protected]> > > For policy questions, send mail to: > Jim Bacher <[email protected]> > David Heald <[email protected]> > > - > ---------------------------------------------------------------- > > This message is from the IEEE Product Safety Engineering Society emc-pstc > discussion list. To post a message to the list, send your e-mail to < > [email protected]> > > All emc-pstc postings are archived and searchable on the web at: > http://www.ieee-pses.org/emc-pstc.html > > Attachments are not permitted but the IEEE PSES Online Communities site at > http://product-compliance.oc.ieee.org/ can be used for graphics (in > well-used formats), large files, etc. > > Website: http://www.ieee-pses.org/ > Instructions: http://www.ieee-pses.org/list.html (including how to > unsubscribe) <http://www.ieee-pses.org/list.html> > List rules: http://www.ieee-pses.org/listrules.html > > For help, send mail to the list administrators: > Scott Douglas <[email protected]> > Mike Cantwell <[email protected]> > > For policy questions, send mail to: > Jim Bacher <[email protected]> > David Heald <[email protected]> > - > ---------------------------------------------------------------- > > This message is from the IEEE Product Safety Engineering Society emc-pstc > discussion list. To post a message to the list, send your e-mail to < > [email protected]> > > All emc-pstc postings are archived and searchable on the web at: > http://www.ieee-pses.org/emc-pstc.html > > Attachments are not permitted but the IEEE PSES Online Communities site at > http://product-compliance.oc.ieee.org/ can be used for graphics (in > well-used formats), large files, etc. > > Website: http://www.ieee-pses.org/ > Instructions: http://www.ieee-pses.org/list.html (including how to > unsubscribe) <http://www.ieee-pses.org/list.html> > List rules: http://www.ieee-pses.org/listrules.html > > For help, send mail to the list administrators: > Scott Douglas <[email protected]> > Mike Cantwell <[email protected]> > > For policy questions, send mail to: > Jim Bacher <[email protected]> > David Heald <[email protected]> > -- Douglas E Powell [email protected] http://www.linkedin.com/in/dougp01 - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
