VFD for Machine Tool

[entropy]

Originally Posted by CarterKraft

I used the cheapest 3hp VFD off evilbay I could find for my old Buffalo drill press.

I couldn't be happier and after not doing it 4 years sooner I was pissed at myself for putting it off.

I still want to hook up the drill presses start/stop buttons add a RPM dial and a foot switch but so far running it all off the VFD itself has been fine.

I've been wondering about putting one on my old 110V Drill press rather then convert it mechanically to run slower...

[TheBandit]

Carterkraft - Could you possibly share a write-up on how you did that? I would love to see.

[entropy]

I ordered and it should be here next week, just one, and figure I'll learn before I buy the 2nd one.
Have to move a bunch of heavy things that are in the way first

E

[Scrambled]

I know it is over kill, but I went with the phase perfect digital phase converter. I have had zero problems with it. It just works. I also have a RPC. It worked fine too, but you had to be careful with the wild leg. Some of my equipment did not like it. All I had to do was switch two wire and everything was better.

Steve

[entropy]

Originally Posted by Scrambled

I know it is over kill, but I went with the phase perfect digital phase converter. I have had zero problems with it. It just works. I also have a RPC. It worked fine too, but you had to be careful with the wild leg. Some of my equipment did not like it. All I had to do was switch two wire and everything was better.

Steve

I will admit that I looked at these but realistically for my application... Overkill

[CarterKraft]

Originally Posted by TheBandit

Carterkraft - Could you possibly share a write-up on how you did that? I would love to see.

Let me take some pix and Ill put one of my world famous incomplete detail lacking build threads LOL.

I didn't clarify but this really only works for speed regulation of 3 phase motors.
If you have single phase tools there will be no benefit.

My buffalo drill press was sitting on the ground at the back of my shop while I was struggling with a POS JET drill press at the front...

[jhovel]

I know you ordered your VFD, so this is for others and future readers:
One of the biggest problems you mentioned is that the information on the 'net is so contradictory (losing HP vs. not losing Hp, for example).
The reason I gather is that many of the opinions are posted by people without sufficient electrical and physics knowledge.
To understand what's going on in a 3-phase motor when you change the frequency of a VFD, there are a number of inter-related things at work. If a person doesn't understand the difference and relationships between torque, speed (rpm) and Hp for a start, then all further opinions are just that - but not fact.
The next issue is that fewer people know enough about magnetic flux, magnetic saturation, magnetic slip and how these are managed by VFDs.
Most VFDs can control not only frequency but also output voltage and output current. Doing so allows them to do soft starts, active braking and DC stopping and locking of the motor. They also maintain torque at the motor shaft across a wide range of speeds and can be set to allow over-power operation for a limited time, should the motor experience brief exceptional loads.
A general point to make is that installation and control setups are actually very easy, but require a little study of the available control parameters and their effects - which is where most people get unstuck. But there is always help available in forums like this one.

I have pretty well all my machine tools running on VFDs in my shop - and only have single phase 240V power supply. In all, I have about 12 VFDs of varying sizes and makes running. Some machines (surface and cylindrical grinders) even have more than one VFD to enable independent control of functions.
I made all the control panels and cabinets myself. This is very safe to do, since the control voltages and currents are much lower than say car electrical systems. No chance of harming yourself or anything else. You get it wrong, the VFD will simply not do what you expect. All it takes is a little study, as mentioned.
VFDs will always outperform rotary converters in terms of efficiency and functions - and I suspect price. They are now very low-cost mass-produced items - almost all made in Taiwan or China, even American or European brands. I have some older European models (Siemens and a couple of Italian ones) which are significantly better quality, alas now also made in the far East and no longer comparable to the old ones - except they are smaller and MUCH cheaper now.
Hope this is of some help to someone.
Cheers,
Joe

[CarterKraft]

my crappy 3 phase VFD post can be found here.