Hey guys just as a quick question. I am sick of my single speed 1hp on my NWGS and am planning to run a 2hp 3 phase off of a VFD. Likely a teco since I am on a bit of a budget due to a new mortgage etc. my question is I currently have a 6 inch drive wheel, so what speed of motor would you recomend? Would I be better to go 1800 and overdrive it when I need to, or go 3450 and under drive it. I assume I am better off with an 1800 overdriven, but wanted to be sure. At 60hz I would be running about 2700 sfpm. How far up could I take it with that setup, and will I lose power by overdriving it? Thanks so much guys.
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Quick VFD question on motor selection.
- Thread starter Grayzer86
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3450 at full speed is perfect for blade grinding.
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Grayser, I'm no expert but I bought a KMG grinder a couple years ago and they are set up with a 5 nch pulley attached to a 1725 RPM motor and a 2 1/2 inch pulley on the jackshaft which drives a 4 inch drive wheel at the belt. KMG so sells a 6 inch drive for those who want a faster top speed but most guys use the 4 inch. The guys that build the grinder in a box have to use a direct drive so they use a 3400 RPM motor direct to a 4 inch drive wheel. The KMG with the 5 inch belted to a 2 1/2 inch pulley doubles the 1725 RPM speed to 3450 RPM which drives a 4 inch drive wheel. It is about the same final speed for both set ups. With your grinder I believe you have to use pulleys to drive the belt so a slower motor would be better if you have a 6 inch drive wheel. This is just my opinion from studying the subject.
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Grayser, I know of least on knife maker that converted a KMG to direct drive so I am sure that you could modify a NWGS to run that way. You might take a look at David Sharps blog. Just google it and you will see many pictures of his grinders including his direct drive mod. Take note that the shaft on a 3450 Rpm motor does not stick way out from the motor so your face mount has to be somewhat thin like 1/4 inch steel which should work fine and you may have to tighten the drive wheel a little further out on the shaft to make it line up. I think it is a simple system and might be better than jackshafts and pulleys or maybe it is such a small improvement that it may not be worth the effort. To me it is always fun to modify something and make it smaller and less complicated. Last I have a Kbac 27 d VFD which is the gold standard for most knife makers and they been selling for about 60% of what I paid a couple yeas ago. I found one for sale from an electrical supply company for $326 plus shipping just yesterday. It's your money but if it were me I would stretch the budget just a little bit and get the KBAC 27 D that is top notch equipment. Larry
I would love to get a kbac but being in Canada cost seems prohibitive. The cheapest I have found it will be over 500 once exchange and shipping is figured in. I can pick up the teco fm50 for 190 shipped, meaning the difference will just about buy the motor. Don't get me wrong, I know the kbac is what I should go for, but for the difference in price I will probably just build a dust proof enclosure. Other than on and off, it will not be adjusted that much, so I am not that concerns with ease of access for right now.
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Try getting a quote at Motion Industries.
You can pick it up in person.
There is already a stock in Canada, so no need to ship them over the border.