[allenj20]

I decided to go ahead and start a thread for this. I finally decided to just get rid of the BLDC and Mikini electronics as I have had a ridiculous amount of trouble with the Mikini electronics over the last three years.

And now that the spindle is actually working I find it is entirely gutless in the low end of the RPM range. So I finally decided there was no other real choice than to gut the Mikini electronics and replace them with parts I know will actually work.

So I have decided to go with an AC motor and VFD setup. And to replace the Mikini breakout board with a more standard CNC4PC bob. So here is what I have so far.

2HP Hitachi sensor-less vector VFD
http://www.driveswarehouse.com/Drive...200-015SF.html

2HP Inverter duty motor
Y368 Products

CNC4PC C23 BOB
CNC4PC

One problem I will run in to is that the new motor weighs 45lbs. The BLDC motor on the machine weighs 22 pounds as I just weighed it. I have one of the original 1610Ls and it does not have a gas strut on the Z axis. So I am going to have to add a gas strut to the Z axis. Anyone have one on their machine and want to post some pictures of how it is mounted so I can get some ideas on how to mount one? Measurements and or specs for the strut would be useful too.

Anyone have any input on pounds of force for the strut?

[Brian L]

I have purchased the gas struts for other things, a good source is Guden Hinges and Industrial Hardware: Guden Home Page, they have them from small poundage all the way up to 250 pounds of force. They also have mounting hardware.

[mcphill]

Why "step down" to a 2 hp motor?

Are you planning to retain the "manual mode" use of the machine, or just bypass all the Mikini hardware and control straight from the PC?

FWIW, here is a solution I was looking at.

Motor: http://www.automationdirect.com/adc/..._to_30HP)/Y541

Driver: http://www.ebay.com/itm/3-HP-Sensorl...#ht_6204wt_910

These would net you a 3 hp power, and a top speed of 5400 rpm. Huge benefits over the system you spec'd, I think... It would cost about twice as much, though...

I am looking at going a different direction now, though. I have found a Vector Drive that will work with the existing BLDC motor on the Mikini. I do plan to order it and see how it goes. Hoping it will be a "transparent" change, but give significantly better control/power out of the motor... I have found the drive I want online, but have had a hard time finding a way to order one so far. Plan to look in to it over the Christmas break...

[allenj20]

It's not stepping down at all. This spindle does not put out 3 HP at any range that is usable for steel or drilling with larger diameter drills. I suspect it does not put out 3 HP at all. That sticker is just a sticker put on in China as far as I am concerned. I have a real mill with a real 3HP AC motor and VFD and there is no comparison this spindle is a gutless wonder and the real 3HP spindle on my other mill never quits no matter what I have thrown at it. I mean this BLDC stalls out on a .50 DOC with a W drill in 6061 at 1000 RPM. That's a cut the X2 mini mill will make without complaint.

Look at the Tormach's 1.5HP and VFD and read their paper on VFD versus BLDC they are closer to the truth. I honestly don't think this is a 3HP BLDC period regardless of the drive used it's a very suspect Chinese 3 HP.

My goal is to get rid of the Mikini electronics all together as they are crap. Why would I try to keep them they are not at all reliable or good.

So the reason I did not go to 3HP is weight and AMPS it would be about 20 amps just for the motor and the motor would weigh close to 70 lbs. Also a real 2 HP will be just fine you will see. The driver you point to is a three phase input FYI. Mine keeps the single phase and the same total 20 AMP input requirement and keeps the weight to a more reasonable 45lbs even at that I am doubling the weight of the motor.

[mcphill]

Wasn't trying to piss in your Cornflakes there!

The drive I linked can be spec'd for single phase as well. I called and spec'd out all the parts from them and discussed the application as well.

I am sure your solution will work, was just curious about some of your specifics and the rationale at why you decided on those specific parts. Please keep us all updated!

[allenj20]

You didn't piss in my cornflakes. What irritates me is the lack of guts of this spindle, not you, so don't misunderstand. Sorry if I came off that way.

I thought a lot about a 3HP spindle but I don't think it really makes sense power wise, weight wise, or even requirements wise for this size of machine. As I said I don't think we are getting anything like 3HP now.

So on the drive you specced if you derate it for single phase you wouldn't get 3HP out of it. Hitachi makes a single phase 3HP VFD see here http://www.driveswarehouse.com/Drive...200-022SF.html but it requires 22 amps all by itself. I don't see on that posting what the amps required for that drive are.

Cheers, Allen

Wasn't trying to piss in your Cornflakes there!

The drive I linked can be spec'd for single phase as well. I called and spec'd out all the parts from them and discussed the application as well.

I am sure your solution will work, was just curious about some of your specifics and the rationale at why you decided on those specific parts. Please keep us all updated!

[mcphill]

You are probably right that 2 hp is more than what we have now, and more than enough for the machine... The Lenze drive is sized for the application specified. I think they actually use the 5 hp version and derate to use it for 3 hp when you supply single phase power. Again, I had a pretty lengthy call with the place where I was going to buy from.

Here's a link to the "right" part: AC Tech SMVector Drive - ESV222N02YXB - 3.00 HP - 9.6 Amp - NEMA 1 Enclosed | | Precision Electric, Inc.

They state 9.6 Amps output - don't see a supply rating...

[Al_The_Man]

I have found a Vector Drive that will work with the existing BLDC motor on the Mikini. . I have found the drive I want online, but have had a hard time finding a way to order one so far. ...

Do you have a link to the drive, I am curious to see a VFD drive that works with a BLDC motor?
Al.

[mcphill]

It took me FOREVER to find it again yesterday, Parker's site is atrocious!

Parker Hannifin, Compumotor Division, North America - A Complete Family of Motion Control Products

http://www.compumotor.com/new_ulm/pd...out%20asrd.pdf

I have yet to actually discuss the application and get the pricing for this option, so I am not 100% sure it will work yet...

[Al_The_Man]

I am just curious how they fit all that into such a small package, where just about all other drive manufacturers need the room to put the large power supply usually associated with VFD and BLDC DC power supply?
Sensorless BLDC has been around for a while but that IS small for a VFD of that capacity?
It resembles more the appearance of a 3ph slow start.
Be nice to see some working applications?
Al.

[allenj20]

Thanks swath that's what I needed.

[allenj20]

Well the motor is here.

[mcphill]

Unless I am mistaken (due to the perspective), Dat's a BIG motor!!!

[allenj20]

You are not mistaken. And it's from the MicroMax series. You can begin to see why I did not go with a 3HP motor it's bigger still of course. As it is this will only just fit I think.

I also ordered the gas struts yesterday from McMasterCarr I ordered 2 50lb struts for 100lbs total they have a 16 inch stroke and a max length of 35 inches.

The VFD should be here this week as well.

Unless I am mistaken (due to the perspective), Dat's a BIG motor!!!

[howecnc]

What does that way?

[allenj20]

45 lbs

What does that way?

[SWATH]

This thread is getting exciting! Thanks Allen, it gives me hope for a productive machine.

[Al_The_Man]

I would be interested to know how those HP curves were obtained?
And what type of control for the BLDC?
Here is part of a application paper that shows a comparison.
The BLDC typically will have max torque down to zero rpm.

Hmm, I wonder if you could try to power the existing BLDC motor with your new VFD controller and see if there is a performance difference. Thant would be interesting.

Do not use a VFD to power a BLDC.
It is designed for different technology.
Al.

[allenj20]

Both sensorless vector drives and BLDC are constant torque variable horsepower. The difference is the VFD has more horsepower at lower RPMs than the BLDC. The BLDC is basically linear horsepower as in the graph.

If our Mikini BLDC setups are truly constant torque it must be like 0.2 ft-lbs or something (just kidding... sort of).

Bottom line I have a BLDC setup I will sell at a reasonable price

Also generally yes VFD are for AC motors. But we were talking about the manufacturers claim that this inverter can drive DC motors.

That's not all that crazy when a VFD puts out a semi-sinusoidal variable freq wave it is doing so with PWM. When driving a DC motor brushless or otherwise you can use PWM to vary the speed you are just not creating an approximation of an AC frequency. Basically both a brushless DC drive and a VFD are DC chopper drives the difference is in the output. It should be trivial to make the VFD dc chopper output a DC PWM pulse. It does this anyway it just fakes and AC wave for the AC motor.

I would be interested to know how those HP curves were obtained?
And what type of control for the BLDC?
Here is part of a application paper that shows a comparison.
The BLDC typically will have max torque down to zero rpm.


Do not use a VFD to power a BLDC.
It is designed for different technology.
Al.

[Krenovian]

Bottom line I have a BLDC setup I will sell at a reasonable price .

Allen, I sent you a PM

Curtis