From: Dave <EMC@DC9.TZO.com> - 2012-05-31 16:28:52
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Looks to me like it is more like a $1264 question. ;-) I don't know. That's why I would try and borrow one first. Know of any plants where you do work that has a spare transformer lying around? I've put a couple of them together before to get the right voltage.. IE 240 to 480 and then 480 to 380 etc. Dave On 5/31/2012 12:06 PM, John Thornton wrote: > I just ran another program to drill and tap a slew of holes in a 1/2" > steel plate with no problems except for I picked the 5/16-18 tap and > drill for the 1/4-20 holes and proceeded to tap all 8 of them at the 20 > TPI pitch... no biggie I'll tap them out to 3/8 and plug them and tap > them over again. > > $64 question will the isolation transformer do the same thing the 7.5hp > spindle motor is doing on the Samson? > > John > > On 5/31/2012 9:43 AM, Dave wrote: > >> You are probably right. When the drive load surges it is likely faulting >> out on what it thinks is a lost phase or phase undervoltage. >> >> It might be interesting is to run this test again and put a clamp on >> ammeter on each leg feeding your Mill and see how balanced the currents >> are. >> >> I have never really had any problem with my phase converter running >> loads so I haven't paid much attention to it, but I think I only have >> run capacitors connected between one phase and the made up phase. I >> know I don't have any >> between both of the two original phases. I was always more concerned >> about the current balance between phases than voltages. The voltages >> have always been within reason ( as I recall ). But then this is one >> of those things that I don't pay much attention to unless it isn't working. >> >> I suspect that the 611 is expecting a stiff power supply - which most 3 >> phase services can provide. If you have a large pulley you can attach >> to your phase converter motor shaft to add inertia to the rotor, you >> might want to attach it. It would help the motor supply surge current >> to the 611 drive. >> >> Dave >> >> >> >> On 5/31/2012 10:04 AM, John Thornton wrote: >> >>> A little update this morning after last night's experiments I built on >>> that a bit this morning. I upped the MFD's on the B-C and A-C caps a >>> little at a time till I got close to what I think I wanted in voltage. >>> This is what I ended up with... >>> >>> Phase ===========> A-B B-C A-C >>> Caps 50MFD 100MFD 220MFd >>> RFC on 246v 263v 271v >>> Samson @440 RPM 246v 247v 249v >>> 611 Drive on 245v 243v 241v >>> Engraving @6k RPM 244v 243v 234v >>> >>> I grabbed a program at random an it turned out to be engraving my >>> company logo at 6k RPM. Now mind you this was not 0 to 6k but 0 to 2k >>> with a 0.09 second pause between 100 RPM increases up to 6k. To my >>> surprise the program ran to the end without a fault including rapids at >>> 295IPM on the Z axis. When I go to town I'm going to snatch up a few >>> more caps to play with and bump up A-C a bit more to try and even it >>> out. This will at least allow me to make parts for the time being until >>> I either get an isolation transformer or generator. The interesting >>> thing that I discovered is if I start up the Samson lathe with the 611 >>> on I get a fault and have to reset the drive. This leads my tiny brain >>> to think that it is a voltage drop to some degree that is tripping out >>> the 611... what do you guys think? When my neighbor gets around to >>> showing me how to store the traces in the scope I'll try and capture the >>> wave form when this happens. >>> >>> Thanks for all the help and ideas. >>> >>> John >>> >>> ------------------------------------------------------------------------------ >>> 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. 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