Post By motion guru
vfd costs and quality.
I have found a supplier that has some discontinued products for sale. They are bran new Emerson Sk drives. They have decided to sell a skb1100075 for $99.00 (110 single phase in 230 three phase out) 1 hp, a ska1200075 (230 single phase in 230 three phase out) 1 hp for $69.00 and a skcd200220 (one or three phase 230 in and 230 three phase out) 3 hp for $99.00. From what i can find on the net this sounds like really good pricing. Any one else think this is a good deal ? They only have maybe two dozen total to unload.
Emerson has used many sources over the years. If you try Emerson's OWN website for those units you cite, several of those were made by Control Techniques show up as 'superseded', 'formerly... and 'no longer ..
Originally Posted by curious george
The SK series still show as a current product line, but..
A) If they are widely available at deep discount, as they seem to be, yet limited in quantity, are they current 'Revision levels'? Stale stock? Or NIB customer return / order cancellation... or what? UNlimited availability would indicate the usual 'list price' game and getting what the real market supports.
B) ANY VFD has an expected life for its filter capacitors, may need them 'reformed' if it has been stored long and used little or not at all.
C) Most older VFD will not have benefited from generally improving technology and new solutions to former problems.
These may be fine units. Or not.
I've been wishing it so myself, more especially for the superseded units available even more economically, but search as I might, cannot find enough independent information either way to yet want to take the risk vs a Teco, Hitachi, or Lenze/AC Tech. And there again, one still wants 'new as possible' to reduce risk of a dud or short-lived unit.
Adding; And BTW $99 for the 3 HP unit sounds really fishy. Even discounted they seem to go for over $300. Even a Huanyang 3 HP gets more than $99.
Actually the drives are not that old. The company that is selling them is a major farm supplier in the midwest. When questioned about them, the supplier said they were for a project that did not come to fruition.(some kind of hydroponic farming operation) Most companies this large would just throw them out and write them off. This company put them in the steals and deals section. With the only description being 1hp vfd drive, and no data (not even the emerson part #) online they were merely overlooked by customers. They were put on sale at half and when that didn't work they halfed them agin.
I just purchased a few of the motors that were to go with the project. One and two hp, brand new, in original packing, Dayton TEFC 3 phase, inverter duty, industrial duty , both at a price of $69.99 each. There are no motors left but there are 20 something drives left. I am contimplating buying all of them and then hocking them on the Internet for $10 more than I paid for them. Everybody would get a really good deal and I would make some beer money.
Seen similar behaviour on cancelled Telecoms projects. If you've been scouting used VFD prices for the past several months , (guilty!), and the source is genuine - then, yes - Helluva deal.
Originally Posted by curious george
Just seemed WAY too good to be true at first glance!
'i got mine' - finally.
Or at least what I think I wanted, given that Altivar 71's are not universally beloved, so good luck with wotever you decide.
Emerson and Control Techniques are the same company via. a ~50 percent stock swap years ago.
The SK drive is a solid drive - and it is far more capable than most of the drives typically used for making 3phase from single phase. And as far as product lifecycle goes - it should be around for a while yet.
Originally Posted by motion guru
Given other tidbits accumulated on your background, I'm taking that as just the sort of assurance I needed. I'll put them onto my 'bargain hunt' search pattern.
One thing worth mentioning is that for the casual / occasional drive user, Emerson/CT drives tend to be less "user friendly" than others. Don't get me wrong, they make great quality drives with lot's of capabilities, but the user programming is, in my opinion, cumbersome and complex unless you already are pretty handy with drive programming. That's why, in my opinion, Emerson C/T abandoned the traditional distribution model here in the US years ago and went with their "Local Drive Center" model, because the LDCs are corporate funded so they can afford to field all the help calls from the field. So if you have an LDC in your neck of the woods, or you are a trained Drives System Integrator, as motion guru's company is, then they are great. But for other geographical areas, mine for one, there is ZERO support for CT drives other than like around here, maybe a few ex-employees still kicking around after the LDC closed a decade ago (if you can find them somehow).
Bottom line: for savvy drive users it's a good drive. But if you like the TECO FM50 yet think the FM100 is too complex, you are probably not going to like the SK drives in my opinion.
Does strike me as more than a bit stone-age that despite what must be a multi-million if not muti-billion dollar niche, not one VFD drive maker on the entire planet has yet hired anyone to write a human-interface instead of making the user learn machine code. And I count the Altivar 71's 'seven language' interface not enough better to matter.
Originally Posted by Jraef
To be fair, programming a PABX with a DTMF keypad and bloody 'beeps' instead of a screen wasn't much better.
That said, the average $100 camera, phone handset, internet / WiFi router, or PC MB BIOS has been doing a better job for Donkey's Years. Doesn't take a great deal of NVRAM to store text messages and a phrase or two of guidance for each of the settings.
Jreaf - you are killing me!
While I admit that the drive has some limitations for visability when programming via the display and pushbuttons, the manuals with detailed flow charts are by far the easiest to follow of any drive I have worked with and if that isn't good enough, download the free software and program it through the seial port with the graphical interface.
And once you have learned the SK drive, you now know virtually every other CT drive whether the Servo, DC, or UniDrive. Same menus with the same parameter numbers and flow charts. Even comes with built in Macros to set up the configuration for a half dozen different common ways to connect the drive I/O and/or run from the keypad.
Puzzled ? The manual that comes with the drive is straight forward. I had no problem programming the drive, was a piece of cake. Biggest problem was deciding on what program to use. Since I used an external 10k thumbwheel pot and a enable switch and a start button the AV.pr was the ticket for me. I am gonna fiddle with the next setup to add reverse for my drill press. Yes you can the free sofware on the cd that comes with it to program it, but to me it was so easy, I didn't bother.
For you bargain hunters out there the site is teksupply.com. they are in the steals and deals section. Better yet just use the part #. Their part #s are
109457 for the SKA120075 which is 240 single in rated at 1.0 hp. The 109527 is kinda cool, its 110 in and rated 1.0 hp. (SKB1100075) The 109548 is a SKC2000220 rated 3 hp.
I suggest any buyers should do their own homework if they need more info. When I was trying to get some info from a saleman , he stuttered and admitted he google the part # and was reading off emersons page. He admitted he didn't have a clue so I said just give me the OEM #'s and I look it up myself. I gave up on the buying and selling idea for beer money, I got to many things to do. Having been a master electrician at the largest UPS manufactured in the US for 30 years has left me with more projects than I will ever complete.
As to the capacitor aging issue, the test papers that come with the drive show sep. 2009. Not that old. I did however read someones master thesis on some edu website and learned a few things. Live expectancy depends on type and conditions. Typical storage for electralitics is 5 to 10 years in storage. What I didn't know was storage is in the box. In use, with power is a new ball game. This explains why the guys 20 year old tv still works. Under power they last a long time. There is even some mil spec for rejuvinating them when they sit to long. Rather interesting, people should check out the facts.