More Tinkering- Drillpress upgrade *w/pics*

[Alan in Little Washington]

My ongoing effort to upgrade some of my woodworking machines recently focused on my Delta 16 1/2" drillpress. My biggest complaint was changing speeds. Since I am a tinkerer I drill both wood and metal which require drastically different speeds. Changing belts was always a pain, especially if having to swap both belts. I decided to convert the drill press to electronic variable speed using a VFD (variable speed drive) which also required swapping out the single phase motor with a 3 phase motor and running them on 220V. In the process I also increased the hp from 3/4 to 1.5 hp. Though you can convert VFD frequency to RPM, I decided to add a tachometer to make it easy to monitor the drill RPM.

Here is the completed unit. The work light was a prior mod as was the Woodpeckers after-market table.

A little closer look shows the digital readout, red speed knob, and small toggle switch; all of which mounted neatly in the front of the original switch housing. The tach is wired so that it powers up and the remote mounted display lighted when power is applied to the VFD with the original large start stop buttons.

Here I have flipped the small toggle switch which starts the drill turning and have turned the speed knob to adjust the speed which is set at 999 RPM in this pic.

The VFD is mounted to a thin steel plate attached to the motor mount below the new Leeson 3 ph motor.

Here is a look inside the pulley cover. I removed the idler pulley (it just lifts out) and in its place I mounted an electrical box and 220V outlet. A power adapter that provides 9V DC for the tach is plugged into the. I will eventual replace the standard V-belt with a Powertwist link belt.

The orange cable in front of the quill pulley goes to the tach pickup which is mounted to the small bracket screwed to the side of the pulley housing. The tach circuit is "mounted" in a "temporary enclosure" (plastic bag :-D ) which will be replaced with a hard case. Also partially visible is the alternating black and white pattern I glued to the top edge of the bottom sheave of the quill pulley which is the target for the tach pickup.

 

[Monty]

Re: More Tinkering- Drillpress upgrade

Awesome! So... you're running a 3ph motor on 220V. I'm ignorant on this topic - why is it necessary to use a 3ph motor for this?

 

[Alan in Little Washington]

Re: More Tinkering- Drillpress upgrade

Awesome! So... you're running a 3ph motor on 220V. I'm ignorant on this topic - why is it necessary to use a 3ph motor for this?

The variable frequency drive needs a 3 phase motor.

 

[michaelgarner]

I wish I could do that to mine, but I dont know any of that stuff

 

[Monty]

Re: More Tinkering- Drillpress upgrade

So the 3ph motor works with the VFD even if the motor is being run on 220V instead of 3ph? Obviously it must! Very nice work!

 

[NCPete]

Re: More Tinkering- Drillpress upgrade

I think I saw elsewhere that the VFD(at some minimal power level?) actually creates a 3phase signal, hence the necessity for three phase motor.

 

[Joe Scharle]

Alan, how did you get 3ph to your house? I'd have to pay for the entire cost of the drop here.
Joe

 

[Monty]

Re: More Tinkering- Drillpress upgrade

I think I saw elsewhere that the VFD(at some minimal power level?) actually creates a 3phase signal, hence the necessity for three phase motor.

OK, I see - kind of the same way the Powermatic 3520 lathe works: it also has a 3ph motor on a 220V circuit, with electronic speed control.

 

[SteveColes]

Man, am I confused:sad9cd: Are you saying that you are using 220 2 phase to run the VFD which outputs 3 phase?

 

[cpowell]

That is a clean installation, Alan. I really like the speed pot and tach feedback. :icon_thum

Did you use 3-phase voltage input to the inverter or single phase?

Chuck

 

[cpowell]

Man, am I confused:sad9cd: Are you saying that you are using 220 2 phase to run the VFD which outputs 3 phase?

Steve, it is possible to supply 3 phase output with a single phase input. Voltage input would be supplied to L1 and L3, with L2 and L3 jumped together to prevent a phase loss fault on the inverter. L1, L2 and L3 are the inverter input voltage terminals.

If single phase input voltage is supplied, the required input current on a 3 phase inverter will be roughly 1.73 times the rated motor Full Load Amps (the rating at max output). Ideally the inverter input current rating would be oversized to roughly twice the motor full load amps in this application. The higher rated inverter would have larger capacitors which will smooth the "ripple effect" seen on rectified single phase AC voltage. Larger capacitors will also provide better filtering of the higher harmonic content seen when using single phase rectified voltage.

Chuck

 

[woodguy1975]

There are drives (inverters) capable of taking in single phase. Any inverter above 5 HP requires 3 phase incoming power. The inverter creates the phases necessary to run the machine. It uses frequency modulation create the variable speed.

To simplify things you can run a 5HP or smaller 3 phase motor on a single phase inverter. Above that HP you need a 3 phase inverter. Again I'll stress the need to not use just any 3 phase motor. The frequency content and lower running speed of a motor on an inverter requires that motor to have thicker insulation and better heat dissipation. You can find (Inverter Duty) motors on ebay all the time. One thing to keep in mind is if you get an Inverter duty motor it can't run on line power. You must power that by an inverter. I seriously don't recommend running a noninverter duty rated motor on an inverter. Especially on a lathe where you may run the motor at a very low RPM with very high load for an extended period of time. That is asking to smoke a motor.

More information than you typically need to know, but since Alan keeps pumping these things out to show you guys to see, you need all the information before attempting to do something similar.

 

[SteveColes]

Alan, would you provide some detailed info. I am interested in the model # of the motor and the manufacturer and model number of the VFD. Also where you got all the tach stuff would also be helpful.

Thanks

 

[toolferone]

Alan,this is very cool stuff. I agree with Steve, a detailed parts list and instructions would be wonderful.

 

[NZAPP1]

I would like the tack info I just picked up a 2- 2 HP VFD's and inverter duty motors on Ebay :eusa_danc One for the lathe and one for the drill press

 

[sapwood]

Alan, that's thinking and tinking. The wizardry is beyond me, but the results are fantastic. It's a feature anyone would love to have on their drillpress :eusa_clap

Two more words: patent attorney :mrgreen:

Roger

 

[Alan in Little Washington]

Re: More Tinkering- Drillpress upgrade

So the 3ph motor works with the VFD even if the motor is being run on 220V instead of 3ph? Obviously it must! Very nice work!

The VFD runs on standard 220V, 60Hz, single phase (or 3 phase) and puts out variable frequency (0 - 400 Hz), 3 phase.

 

[woodguy1975]

Alan,this is very cool stuff. I agree with Steve, a detailed parts list and instructions would be wonderful.

I'm still suggesting an inverter duty motor. I know Allen didn't use one, but you really should especially if you plan on running on the lower rpm range.

John

 

[Alan in Little Washington]

Ok, ok. A few more details. First, Woodguy is right about overheating a motor if you are not using an inverter duty motor, or not careful using a VFD (variable frequency drive.) There a lot of details I left out because I didn't want to bore you.

To answer a few of your questions, my shop has standard single phase 110/220V power. VFD's come in many different configurations. Two of my VFD's run on 220V one will run on 110V or 220V. Some VFD's require 440V input and output 440V. My VFD's can run with single phase power input. Some VFD's need three phase input power, others will work on either single phase or three phase. The output of all of my VFD's is 220V, 3 phase, hence the need for a 3 phase motor.

First, due to the way VFD's control RPM, by varying the frequency of the output power (some VFD's have outputs rated at 0 - 400 Hz) the speed of a (3 phase) 3450 RPM induction motor can be varied from 0 to over 5000 RPM. You don't get something for nothing, however. At high motor RPM, overheating is not a problem, but premature bearing wear can be. The problem comes at low frequency/RPM. Without going into the technical details, due to the way the iron and the magnetic field in the motor react, motors can overheat when run with low frequency (less than 60 Hz) power. They also lose torque at low RPM. For this reason you will notice many of the variable speed VFD lathes like the Delta, still require some belt changes. The Nova DVR lathe uses a specially designed DC motor (the motor is the headstock.) There are motors designed to work with inverters (VFD's). The main differences with "inverter duty" motors, is not that they can't get hot also, but they handle it better- they have better air flow through the motor and the temperature rating of the winding insulation is much higher than a standard motor.

For those wanting to attempt this kind of modification to your tools, I strongly recommend that you spend some time educating yourself on VFD's first. You need more than basic electrical knowledge and skills to install and wire it. All but the most basic VFD's have many parameters (my drill press VFD has almost 60 parameters) that you must program. While they have default settings, most require that you tailor at least some of the settings to your specific application. Examples of parameters are: minimum freq, starting freq, max freq, ramp time/rate, overload, switching rate, decel time, dynamic braking, torque boost, and many more. While some VFD's work on 115V, most need 220V. They have capacitors inside, generate high voltages, and have currents that can severly shock or kill you. You would not believe the number of PAGES of cautions in the manual for one of the VFD's. By the way, none of my mods are permanent, and each tool can be returned to its original configuration.

I made conscious tradeoff decisions with my two applications.

As far as the lathe goes- I set up the motor to spindle pulley ratio at almost 3:1 so at low spindle speeds I am still turning the motor at a reasonable RPM. I don't do production work and don't spend long hours at the lathe. The lathe motor (a Baldor), while not VFD rated, is a well made, open-drip proof design that has good airflow. It is close at hand so I can easily monitor the temp. It is double the hp of the original lathe motor. At the low prices I paid for both the VFD and motor (on Ebay) I feel I can afford to take a chance with overheating. By the way, prices have gone up on all this stuff since I bought them. Though you can still get 3 phase motors fairly reasonably, VFDs in the 1- 3 hp range seem to be going for much more.

Much the same can be said about the drill press. One big difference here is that the drill press doesn't run nearly as long or require nearly as much torque. But as I said, I am continually going back and forth between drilling metal and wood and have been really bad about running it at the proper speed because of the awkward belt/pulley changes. So I felt a VFD was worthwhile. Now I will keep a speed chart by the drill press and be able to quickly and easily set the proper speed for the material being drilled and the bit size.

As far as the tachometer, it is a great little device for those who want to know the RPM of a drill press or RPM and SFPM (surface feet per minute) for a lathe, mill, etc. Here is the link to MKC Tools. They now offer a KB DC motor drive with built in tach package. A DC motor is another option that you might want to investigate, though 1-2 hp DC motors can be hard to find and a little expensive also.

Detailed instructions and parts lists would be of little use due to the nature, wide variety, and availability of this stuff and the fact I got mine off of Ebay. At new prices this installation could cost between $500-$1000. This is not an easy plug & play mod. I have a nice little Baldor VFD that I couldn't use because I couldn't program it for remote operation- though the model # matched, the software program did not match the manual I got on the Baldor web site.

If you visit Little Washington, I'll talk your ear off about this stuff, but a written "how to" would be too difficult.

 

[woodguy1975]

I would recommend against any open style motor like a drip proof. They don't handle a dusty environment of a shop well at all. I know Alan knows what he is doing so he will kee an eye on it, but you've gotta think about the environment.
Did you know that just because a motor is TEFC (Totally enclosed fan cooled) doesn't make it dust proof? There are additional seals that must be added to those motors to keep the dust from prematurely wearing out the bearings of the motor along with clogging the centrifugial switch if it is a single phase motor. There is a lot of knowledge that you must have before you make modifications on your own as Alan has also stressed. I would not do anything like this on your own without doing your research and knowing what you are stepping into. I'm willing to provide help to anyone as is Alan I'm sure, but in the end you need to bring yourself up to speed on what not to do and what you can do.

I have designed and built a number of large machines professionally and even when you think know what you are doing you'll find you didn't know it all. :eyeslam:Every drive (inverter) is different, every application is different.....