Vfd???

W

wassomeoneelse

Joined
Jan 19, 2007
Messages
123
I am in some serious need of information about VFD control vs a three step pulley. After talking with the wife about ordering a KMG grinder, I figure anything that I can save on will allow me to get the attachments that I want for the machine, but at the same time allow me to have variable speed. If it doesnt work out cost wise, I have no problem going with a three step pulley to control the speed. I am thinking about buying a three phase motor and control and installing it with the help of a friend. I talked to a salesrep from automationforless and he said the following microdrive would be all i needed for running my kmg "along with the appropriate 3 phase motor". I need some feedback on this. He said that it would take in one phase and change it to three phase to the motor. Am I missing something? :confused: It doesnt seem like it is too expensive at all. Just need some opinions on this product... along with any ideas that I could do it myself at a reasonable cost.

http://www.automation4less.com/store/proddetail.asp?prod=X200-015NFU

Thanks
Bryan
 
It looks like it would probably work but it looks to have a NEMA-1 enclosure which is
not proof against conductive dust. That's what I have and it hasn't died in about 2 years but
a number of people on this forum have seen their expensive VFD's go POP suddenly.

The controller that Rob Frink sells has NEMA-4 enclosure which eliminates this threat. That's
why it costs more. If I had understood this when I bought my KMG I would have gone with
a controller from Rob just for the peace of mind.
 
Well, I want to first say thankyou for the responses that were given. I learned something new about nema 4. I will keep that in mind while I look for a vfd. It definately gives me something to think about. I think I am leaning towards just ordering it from Rob and buying the extras when it is Christmas and my birthday.
Again,
Thanks,
Bryan
 
wassomeoneelse said:
I think I am leaning towards just ordering it from Rob and buying the extras when it is Christmas and my birthday.
Click to expand...

That's exactly what I did and I have NO regrets. Let's face it, Rob has already done his homework. You may luck out and find a better deal somewhere else, but peace of mind is worth something too, and Rob stands behind what he sells.

Good luck with your purchase and let's see some pics when you get her set up!!!:thumbup:
 
I saw a picture of a VFD NEMA-1 set up in a large-ish light metal box with Hollywood type air cleaners on both ends. There is something about how much enclosure volume is necessary and I can't find the link to the thread... it's here somewhere. Might be a person could contact the manufacturer and get some ideas about what is needed.

Mike
 
See the links on page 2 of this thread for various VFD's - the posts by Stacy and myself
including codes for nema 1 and nema 4 enclosures

http://www.bladeforums.com/forums/showthread.php?t=563787&page=2

It is so much cheaper to do it now. You can save yourself from buying 2 motors when you upgrade later- just get the 3 phase you need for the VFD and be done -
You can also save this way - 3 phase motors are usually cheaper than the equivalent single phase - used in industry - lots of surplus about.


Stacy also has some valid points re DC motors and full torque at low speed ( DC motors cost more though )
 
Last edited:
Look on ebay for a Dc motor


I snagged a Baldor 2hp for 250 bucks

Msrp is like 2 thousand dollars or something insane on the baldor website

but you can probley get one for pretty cheap if you look around

I cant stop mine period but i can slow it down but its usually at the top end speed
 
The VFD doesn't convert single phase to three phase power. You either have to have 3 phase service from the power company or you have to use a phase converter.
 
RUGUR said:
The VFD doesn't convert single phase to three phase power. You either have to have 3 phase service from the power company or you have to use a phase converter.
Click to expand...

That all depends on your VFD. I have 2 Siemens Micromaster VFD's (.5 kW and 1.5 kW) and they are both able to convert 1 phase to 3 phase...

Cheers Rody
 
Excuse me. What I really meant to say was, I don't believe the other VFDs that have been mentioned in this thread do convert single phase to three phase power.
 
The 95% of electronics in the VFD don't care how it is fed - 3 phase or 1 phase.
Both get rectified into a DC voltage and then the VFD magic happens. The reason
higher HP VFDs require 3 phase has to do with limiting input current to reasonable
values.

To simplify, feeding VFD via 3 phase requires only 1/3 of current, per phase, compared to delivering the same power via 1 phase. So you have less of resistance loss, heating of wires and don't require as thick of wires and as powerful of breakers etc.

Also, most industrial shops do have 3 phase available to them.
 
Sure Mike, It's a FM50, 3hp, 220 in 3ph. out from Factory Mation
http://www.factorymation.com/s.nl;j...e3eSc3uNaNuTe34Pa38Ta38Mc350?sc=2&category=32
They had by far the best price when I was looking. Mounted in an old Craftsman tool box with generic air filters from Advance. I was going to put a muffin fan but a friend who almost has a Phd. in electrical engineering looked it over and said that wasn't necessary. No heat build up problem so far. The VFD is bolted to a piece of 1/4" aluminum for additional heat sinc. One cord is 220 in and the other is the 3 phase out going to a receptacle. I have male plugs on the equipment. It generally stays with the belt grinder. I infrequently use my surface grinder so it is no problem to just carry the box over to the other machine and plug it in. And the same with my lathe when I get around to putting a 3ph motor on it. The box isn't airtight but it is pretty much dust proof so far. It could be made more so with some cheap weather-stripping around the lid. It's worked real neat for me for a couple of years now. I picked up several matching plug/receptacle sets on e-bay so only need to add a plug to anything needing 3ph carry the box over and go.
Matt
 
the price still is the best, 2 years later. An excellent deal !

Do you operate it via the smallish console or have separate switches and POT for
RPMs ?
 
matt walker said:
Sure Mike, It's a FM50, 3hp, 220 in 3ph. out from Factory Mation
http://www.factorymation.com/s.nl;j...e3eSc3uNaNuTe34Pa38Ta38Mc350?sc=2&category=32
They had by far the best price when I was looking. Mounted in an old Craftsman tool box with generic air filters from Advance. I was going to put a muffin fan but a friend who almost has a Phd. in electrical engineering looked it over and said that wasn't necessary. No heat build up problem so far. The VFD is bolted to a piece of 1/4" aluminum for additional heat sinc. One cord is 220 in and the other is the 3 phase out going to a receptacle. I have male plugs on the equipment. It generally stays with the belt grinder. I infrequently use my surface grinder so it is no problem to just carry the box over to the other machine and plug it in. And the same with my lathe when I get around to putting a 3ph motor on it. The box isn't airtight but it is pretty much dust proof so far. It could be made more so with some cheap weather-stripping around the lid. It's worked real neat for me for a couple of years now. I picked up several matching plug/receptacle sets on e-bay so only need to add a plug to anything needing 3ph carry the box over and go.
Matt
Click to expand...

What spec are the switches and pot, and where did you get them? I am quickly starting to really like your idea.
 
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