Well I'll be a monkeys uncle, the step up transformer does have a N lug but nothing is connected to it.
Voltages at the drive input are UV 525 UW 512 VW 508 Ug 225 Vg 225 Wg 370 John On 5/29/2012 6:44 AM, gene heskett wrote: > On Tuesday, May 29, 2012 07:33:26 AM John Thornton did opine: > >> While laying on the floor to change taps yesterday on the step up >> transformer I noticed it says INPUT WYE. The transformer has 3 sets of 3 >> lugs for input 208, 220, 240. The only other wires on the transformer >> are 3 lugs for 390v to the infeed unit and 3 lugs at 480v for the >> cooling pump. The step up transformer frame is grounded to the same >> place as everything else in the machine. >> >> John >> > You said "INPUT WYE", but made no mention of a center N connection. How > can it be a WYE if there is not a neutral? Perhaps I'm still a pint low on > coffee? > > More to the point, what voltage do you actually measure, to ground, from > those 390 volt points? > >> On 5/28/2012 8:34 PM, Dave wrote: >>> Yes, many/most big servo drive systems that I have worked on use a >>> Delta primary - Wye secondary with a grounded neutral. >>> >>> I think the grounded neutral on the Wye keeps the voltage in check on >>> the drive capacitors from a line to ground standpoint. >>> >>> I've purchased this type of transformer for a couple of different >>> servo projects. They tend to start at about 10 KVA and cost about >>> $1200 at that size. >>> >>> I think I have a 6 KVA unit in my shop. Hmm... come to think of it, I >>> have used that transformer to power Siemens VFDs and Parker servo >>> drives off of my rotary phase converter without any problems. >>> >>> If you were closer, I'd loan it to you. >>> >>> Delta primary, Wye secondary transformers are pretty common around >>> here. But many are sold specifically as drive isolation >>> transformers. >>> >>> You have a step up transformer in your machine right now though, prior >>> to your Siemens 611U power input module (fancy DC power supply); How >>> is that wired? >>> >>> Dave >>> >>> On 5/28/2012 8:05 AM, John Thornton wrote: >>>> Gene, >>>> >>>> The phaseperfect install guide did mention that when you need >>>> balanced voltage to ground to use a delta wye transformer after >>>> their device. So I have to assume they are out there but so far my >>>> google only turns up descriptions of the beast. >>>> >>>> John >>>> >>>> On 5/27/2012 4:09 PM, gene heskett wrote: >>>>> Now, here John, is another thought if my train of thought follows >>>>> and this thing is hooked up delta on the outside, but is 3 >>>>> individual loads to ground inside the kit, and which I can see >>>>> objecting to the over voltages the phase converter generates,you >>>>> might be very pleased with how it works IF you interpose a 3 phase >>>>> transformer between your phase converter output and the supply to >>>>> this kit. Hook the input side up as a delta load, ignoring the >>>>> center of the wye this idler motor has AND the center of the >>>>> primary side wye (other than making sure, if it has individual >>>>> bolts per phase, that they are connected together). >>>>> >>>>> Then ground to the machines neutral and effectively to ground, the >>>>> center of the wye of this 3 phase 1/1 transformers secondary, and >>>>> feed your kit with the outside 3 corners of the wye. That should >>>>> go a long ways to restore the "to ground" voltage balances. The >>>>> transformer will of course need to be rated at about 125% of the >>>>> kits actual load. And not having researched it, I'd have no clue >>>>> as to the ready availability of such a beast. >>>>> >>>>> Doing a google search, I came across this: >>>>> >>>>> <http://www.elec-toolbox.com/usefulinfo/xfmr-3ph.htm> >>>>> >>>>> which might make it a bit clearer than my word pictures. >>>>> >>>>> Cheers, Gene. >>>> --------------------------------------------------------------------- >>>> --------- Live Security Virtual Conference >>>> Exclusive live event will cover all the ways today's security and >>>> threat landscape has changed and how IT managers can respond. >>>> Discussions will include endpoint security, mobile security and the >>>> latest in malware threats. >>>> http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ >>>> _______________________________________________ >>>> Emc-users mailing list >>>> Emc-users@lists.sourceforge.net >>>> https://lists.sourceforge.net/lists/listinfo/emc-users >>> ---------------------------------------------------------------------- >>> -------- Live Security Virtual Conference >>> Exclusive live event will cover all the ways today's security and >>> threat landscape has changed and how IT managers can respond. >>> Discussions will include endpoint security, mobile security and the >>> latest in malware threats. >>> http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ >>> _______________________________________________ >>> Emc-users mailing list >>> Emc-users@lists.sourceforge.net >>> https://lists.sourceforge.net/lists/listinfo/emc-users >> ------------------------------------------------------------------------ >> ------ Live Security Virtual Conference >> Exclusive live event will cover all the ways today's security and >> threat landscape has changed and how IT managers can respond. >> Discussions will include endpoint security, mobile security and the >> latest in malware threats. >> http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ >> _______________________________________________ >> Emc-users mailing list >> Emc-users@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/emc-users > > Cheers, Gene ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
