[barchdesigns]

I have a vertical CNC Mill with a Fanuc 6M controller and everything works great. However I'm trying to find a way to make the machine draw less power upon spindle spin-up and spin-down.

See, in the next few months I will be moving it to my garage at my home without 3 phase power. After talking with our power company it is going to be really expensive to bring in 3 phase power, and also fairly expensive to get anything bigger than a 200 amp service brought to the house.

I've done some measuring and it seems the only time the machine really draws any real power is when the spindle spins up and spins down. When it is running I only pull about 8 amps on each 3 phase leg (which I think roughly converts to about 13.8 amps on a 220V single phase line). Upon spindle spin-up it pulls about 44 amps on each 3 phase leg (75.9 Amps on 220V single phase). I've talked to a 3 phase rotary converter manufacturer and they said that I should get a rotary converter double the size of what the machine uses to make sure the voltage leg-to-leg doesn't drop too far. That means I would need a single phase 150 Amp service to run the 3 phase converter to run the CNC machine. This seems especially wasteful.

So ultimately I called Fanuc to find out if there was a parameter in the 6M controller to make the spindle take longer to spin up so it wouldn't draw such a heavy load over a short time. They said No.

I replaced a Spindle Drive in my Mazak with a Toshiba VF-S11 Drive about a year ago and it actually has this parameter. It seems the old Fanuc and old Mazak work very similar with just an analog 0-10V signal to the AC Spindle drive.

Any Ideas on what to do on a budget? I've thought about replacing the Fanuc spindle drive with a $1,500 Toshiba drive so I can set this parameter and make the machine draw less power over short durations. Taking 20 seconds to spin the spindle up is OK with me and would draw less power. However I don't know what I am getting myself into with trying to replace a Fanuc Drive.

Another idea I had was to make a small circuit with a programmable chip that would sit in between the 0-10V Fanuc signal, and the AC Spindle drive. The chip would slowly ramp up the 0-10V voltage over 20-30 seconds so the AC spindle drive would slowly spin the spindle up. Would that work? If so that sounds like a $5 solution. Does the Fanuc 6M have a "RPM speed reached" signal before moving the Axis?

Any ideas on how to make this machine work on limited power? BTW It's a Mitsui Seiki VR3A

Thank You
Benjamin Barch
Barch Designs
877-201-9771

[Al_The_Man]

Did you check the drive itself to see if there are any Pots that would adjust this?
Most CNC spindle drives use a Up-to Speed and At Zero Speed output.
Al.

[barchdesigns]

I just had a look and I there are many pots on there. What an easy solution that would be! Taking a first glance, there isn't much for descriptions on the circuit board itself from what I see. The machine is currently running so I don't want to open the hinge to reveal the layers of the drive until power is off.

Do you know where I can get a schematic or manual for a Fanuc A06B-6044-H008 AC Spindle Drive?

[Al_The_Man]

You may be luck and the pots may be labeled.
Good luck getting schematics for Fanuc equipment, you may be in luck finding one if it turns out to be a 3rd party drive, some of the early 6 DC spindles were Mitsubishi Sp. drives.
Al.

[barchdesigns]

This seems promising....Here is what I found. On the front board A20B-0008-003 there are 11 pots and 7 LED's labeled as follows:

POTS
RV1 - TS Offset
RV2 - MS Peak Level
RV3 - Slow Down Reference
RV4 - AMS Peak Level
******************************RV5-RV7 = High
RV5 - Slow Down Time
RV6 - Gain
RV7 - In Position
******************************RV8-RV10 = Low
RV8 - Slow Down Time
RV9 - Gain
RV10 - In Position
RV11 - Position Shift

LED's
LED1 - Orientation
LED2 - Low
******************************LED3-LED5 = Indicators for adjusting
LED3 - MS Peak Level
LED4 - Slowdown Period
LED5 - In-Position Fine
LED6 - In-Position
LED7 - Test Mode


I am not sure what the acronyms are for (MS, AMS, TS). Would you help explain what those are? It seems like it may be as simple as adjusting the Slowdown Time pots, but would this affect the spin up time as well? Any help is greatly appreciated. Al_The_Man you don't get enough credit around here. You're one incredible source of knowledge! Thank You

Benjamin Barch
Barch Designs
877-201-9771

[Al_The_Man]

In adjusting pot on an unknown drive it is a case of recording the settings and adjusting one at a time a small amount and check the effect.
I imagine Gain will be one that may have the desired effect, also slow down times, hopefully?
Sorry I can't be of more help.
Al.

[jdeere4250]

do not touch the pots on the -0030 as they are orientation adj. if machine is doing good tool changes let them alone. this drive is as good a drive as you can get. the thing you need to change are acc/deccl pots on the -053x or -069x borad or the big board. ill let you know later.

[barchdesigns]

I've decided to hold off on adjusting anything. We're getting 320A electrical service to the house/garage now and I will be using a big enough 3 phase rotary converter so I won't need to adjust the spin up and spin down times. Thanks for the info, I would have normally just started dialing things around to see what happens. Looks like that could have been a bad case this time.