looking to get something like a variable frequency drive, but don't need something that costs $850
looking to get something like a variable frequency drive, but don't need something that costs $850
(OP)
I want to get a 5 hp, 1800 rpm electric motor, and run it from 0 to 1800 at a steady rate. Variable frequency drives are all huge, very expensive units that have multiple applications. Does anyone know if there is something simpler? I literally just want a knob that I can turn from low to high frequency. Is this possible?





RE: looking to get something like a variable frequency drive, but don't need something that costs $850
I will of course buy it off of my local distributor for a LOT less than that and make a very tidy profit selling it to you for that price by the way...
"Will work for (the memory of) salami"
RE: looking to get something like a variable frequency drive, but don't need something that costs $850
1 - it should be 3 or 5 hp (I think for its application, the more torque the better)
2 - i want to be able to run it from 0 rpm to its max rpm
What kinds of products should I be looking at for this?
Please and thank you!
RE: looking to get something like a variable frequency drive, but don't need something that costs $850
"Will work for (the memory of) salami"
RE: looking to get something like a variable frequency drive, but don't need something that costs $850
RE: looking to get something like a variable frequency drive, but don't need something that costs $850
Big difference between 5HP and 10HP. What happened?
Maybe you should elucidate the entire concept here.
"Will work for (the memory of) salami"
RE: looking to get something like a variable frequency drive, but don't need something that costs $850
www.KilroyWasHere<dot>com
RE: looking to get something like a variable frequency drive, but don't need something that costs $850
Mike Halloran
Pembroke Pines, FL, USA
RE: looking to get something like a variable frequency drive, but don't need something that costs $850
You haven't search hard enough. Try Ebay or Automation Direct. Under half your price, or less.
RE: looking to get something like a variable frequency drive, but don't need something that costs $850
Just be very careful with FleaBay drives old drives that have been sitting on a shelf somewhere can often suffer from an early demise because capacitors inside of them degrade if not powered up. There are things you can do about it if you have the right tools, but from the nature of your question, you would be better served by steering clear of them.
There are also a lot of VFDs being sold on FleaBay now that are being spewed out of a factory in China often with no brand name on them or you can see the name Huanyang in the photo, but never mentioned in the ad and sold at impossibly low prices. Those are absolute trash and are of such poor quality that people have to go through 3 or 4 replacements to get one that works out of the box. In many cases, the vendors are front companies of surplus junk dealers who buy them in bulk, sell them dirt cheap, then disappear before they have to replace anything. The mfr in China will refuse to honor any warranties, they will tell you to take it up with your vendor, who is long gone (or has changed names).
"Will work for (the memory of) salami"
RE: looking to get something like a variable frequency drive, but don't need something that costs $850
That doesn't really matter all that much though. I've basically been told to just source the necessary components, and I'm looking for my best priced most suitable options. I believe that it is a 10hp, 3 phase, 230V motor. As well as a VFD that is capable of running linearly through a minimum to maximum RPM range so that I can do testing. Someone had suggested I use a gear box, and just switch the RPMs, but I want to run the full range.
RE: looking to get something like a variable frequency drive, but don't need something that costs $850
RE: looking to get something like a variable frequency drive, but don't need something that costs $850
"Will work for (the memory of) salami"
RE: looking to get something like a variable frequency drive, but don't need something that costs $850
RE: looking to get something like a variable frequency drive, but don't need something that costs $850
RE: looking to get something like a variable frequency drive, but don't need something that costs $850
That's potentially useful information: if you expand a bit on the reasons why then someone might be able to offer some ideas on a solution.
FWIW, 10HP sounds like a massive motor for these tests, especially with a 3:1 torque multiplication. Is there any credible service scenario that would see the valve rotate at 600 rpm? I work with a lot of valve actuators and I have never seen any valve operate above 100 rpm, and most are a fraction of that. I'm not saying you're wrong, I'm just curious.
RE: looking to get something like a variable frequency drive, but don't need something that costs $850
You need an indexer that runs at representative speed, with representative dwell times. Actually, pseudo- random dwell times would probably be a better choice.
Mike Halloran
Pembroke Pines, FL, USA
RE: looking to get something like a variable frequency drive, but don't need something that costs $850
RE: looking to get something like a variable frequency drive, but don't need something that costs $850
DC motors are expensive relative to AC types, especially relatively large ones like 10HP. I think you're on the right track with an AC motor plus VFD, because while you could solve this using a DC motor and drive you'd almost certainly spend a lot more money doing so.
RE: looking to get something like a variable frequency drive, but don't need something that costs $850
Your basic premise is akin to saying "I need something like a car, but it doesn't need to have a stereo or a cigarette lighter, it just needs to move down the road when I step on the throttle and stop when I step on the brake."
"Will work for (the memory of) salami"
RE: looking to get something like a variable frequency drive, but don't need something that costs $850
A VFD is essentially a constant torque device and is linear power between the speed ranges you are looking for. You will not get "10hp" at slow speeds required.
Your opening post referred to cost as a big issue. You could be paying 3x more if you just look at power rather than torque if your speed range is 3:1.
It seems an odd test, to be honest. What are you looking to measure? Just leakage? I assume you will need some means of determining load at specific speeds, so if you are "way over-rated with the drive system" what is it you are actually testing and therefore, why are you concerned about cost?
I would have thought the major 'cost' would be the measurement equipment and, ultimately, the overall quality (or not) of her rotary valve you manufacture.