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Power Sag
Thanks CalG, and my apologeez anyone else. I did not read the original post closely enough. "less than a second" :nutter: Sorry. Cap's or Xfmr fields can act as buffers but I think care should be taken using this approach on a phase converter... What's having problems with the sag...- Doug S.
- Post #5
- Forum: Transformers, Phase Converters and VFD
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Two motors on one VFD
Yes you can. However: 1 - Normally you would have two loads combined to be smaller than the nominal hp of the drive. For reasons you can guess. 2 - The drive will NOT like the switch drawn on the cooling pump circuit. 3 - Do you really want to have your pump tied to the VFD? I should think...- Doug S.
- Post #3
- Forum: Transformers, Phase Converters and VFD
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Power Sag
Bigger wire. Where you need the bigger wire depends on the "origin" of the sag. Is the voltage dropping at your branch circuit only, feeding panel, or all the way back to your source? FWIW if you wanna sound like you know what yer talk'n about use the term voltage drop. Good Luck, Doug S.- Doug S.
- Post #3
- Forum: Transformers, Phase Converters and VFD
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Inexpensive pressure sensors
Pierce, I have no cheap sources, especially for a chlorine environment, with an analog output. My guess would be a local surplus guy? There is an abundance of surplus right now. However, have you considered making a flow sensor? A spring, a flapper, and a pot would do the trick. Another...- Doug S.
- Post #4
- Forum: Transformers, Phase Converters and VFD
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Specs for a transformer?
Running a VFD rated a bit larger than the rated motor is a good rule of thumb. However, I doubt this will be a production machine? And I doubt you'll be hogging out deep cuts with the feed cranked up? You'll probably be fine using the VFD with the current motor. Have fun, Doug S.- Doug S.
- Post #5
- Forum: Transformers, Phase Converters and VFD
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Specs for a transformer?
I am NOT familiar with that specific lathe, but I'm guessing you'll be money ahead to find a more standard motor. (Can you pull the motor?) Running it from a VFD would be another route. You can spec. the motor voltage and base freq. in most VFD's but you'll need to start w/ a 480v vfd, which...- Doug S.
- Post #2
- Forum: Transformers, Phase Converters and VFD
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VFD review
Sounds like you have a good grasp on the situation. As usual, the devil is in the details. When you find 'm let us know. Plenty 'o folks here that have already dealt with any problem/mistake you come across. Doug S.- Doug S.
- Post #2
- Forum: Transformers, Phase Converters and VFD
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y vs delta in the wiring
Peter, have you been reading your code book? ;)- Doug S.
- Post #9
- Forum: Transformers, Phase Converters and VFD
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VFD rated more than motor ?
Not only is that not a problem, but is suggested by yours truly, and common practice. You will want to set the drive parameters to match the limits of your motor! Nothing to calculate here, you need a 400v drive. OR look to see if the motor can be wired to run at 220v. This info would be on...- Doug S.
- Post #2
- Forum: Transformers, Phase Converters and VFD
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Royersford Excelsior 21
My 20N will take over an inch... never done it, never (really) used it. (Came with my lathe, for my lathe.) It would more than likely overcome the counter weight, it's a beast. As mentioned MT bits require patience or cash. I'd watch local (or regional) auctions, they can go really cheap...- Doug S.
- Post #29
- Forum: Antique Machinery and History
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Royersford Excelsior 21
I know Andy's mentioned this before, and I'm pretty sure I've made this reply before... =) My 18n hangs fine on Royersford. However if I stick a 9" long 3/4" bit in, it doesn't return with out help. =) Doug S.- Doug S.
- Post #23
- Forum: Antique Machinery and History
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motor voltage ?
Take a closer look at the name plate. The motor can probably be wired for a lower voltage, and it sounds like it is. I see bigger imbalances on new(ish) motors fed from POCO generated 3 phase. Doug S.- Doug S.
- Post #6
- Forum: Transformers, Phase Converters and VFD
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Papplewick's Pumping Plant Poses Problem for PM Poster
Your titles are of no concern to the likes of me. If I see you are the author I can be certain of eye-candy. Thanks, Doug S.- Doug S.
- Post #10
- Forum: Antique Machinery and History
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motor voltage ?
I thought that's what I said. That aside, you are correct, I just was trying to spoon feed. =) Doug S.- Doug S.
- Post #4
- Forum: Transformers, Phase Converters and VFD
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motor voltage ?
It might but not for very long. If the motor is wired for 575v you are putting over double the current through the windings. The internal motor "wires" are not designed to sustain these current levels and the motor will burn up in short order. The motor will use less current when there is no...- Doug S.
- Post #2
- Forum: Transformers, Phase Converters and VFD
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a LITTLE HELP ON TIME VS CURRENT GRAPH FOR BREAKERS
If your wire is already "over sized" ( Is it #8,#6, or larger? ) spend the $10.00 to $20.00 for the appropriate larger breaker. You can purchase breakers listed to run at 100% of their rated load. This way when the building burns down from something totally un-related you might still get your...- Doug S.
- Post #14
- Forum: Transformers, Phase Converters and VFD
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Nimhcells for rebuilding cordless power tools
As mentioned stick with ni-cad, that's what's coming out. ALSO I have found the NIMH is no fun when it's been sitting for a couple of weeks. You grab your bat-drill to zip in a screw and it's got no zip. Ni-cad has a few advantages yet... My 2¢ Doug S.- Doug S.
- Post #5
- Forum: Transformers, Phase Converters and VFD
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Puzzling VFD/motor interaction
I am wondering if Vector is of any benefit on a planer? ( I might be missing something? ) My 1.5¢ Doug S.- Doug S.
- Post #7
- Forum: Transformers, Phase Converters and VFD
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Starters and relays
Visible or audible sparking? =) You probably have a bum contactor, but as mentioned MAY have other problems that are causing contactor to act up. Is the contactor coil itself chattering or does it appear/sound like it's solidly pulled in? Have you checked any thing with a meter? ( are you...- Doug S.
- Post #6
- Forum: Transformers, Phase Converters and VFD
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two motors running one machine
Might, but then at that point you couldn't simply purchase the 15hp motor...:confused: Also, you CAN run two motors from 1 vfd, but it would need to be sized accordingly. Along with a bunch of other considerations, it would be pointless unless you already had the stuff on the shelf and didn't...- Doug S.
- Post #9
- Forum: Transformers, Phase Converters and VFD