Brushless motors

[sp1nm0nkey]

I've seen several people replace their spindles with AXI outrunner motors, but haven't been able to find much information on what materials they were cutting afterwards. I'd like to not lose my ability to cut stainless and titanium. I'm not so much interested in higher spindle speeds, just the ability to change speeds faster. Thing is, I have spare brushless outrunner motors lying around... that's why this is so appealing. As far as driving the motors goes, I was planning on using a switch mode power supply and a micro controller to generate the pulse train to chose speeds.

Also, how noisy is the machine after installing the new motor?

[ee_t]

Whats the model # of the largest motors you have laying around?

The noise would depend on your drive method, if its direct, what kind of coupling. If its divided down, what type of belt. I see no reason if using a v-belt it would be any louder than a stock taig, as long as the RC motor has decent bearings.

Some related threads but I didn't see any answers to your questions:
Can RC Brushless Motors be used as Spindle Motor ???
Sherline spindle motor suggestions?
High Speed Spindle for SIEG X2 Mill - getting technical

[Vermiculite]

I was impressed with the setup that this guy has on his taig cnc mill ( http://www.recumbents.com/WISIL/shumaker/default.htm ). I am considering it myself. You can get some monster outrunners pretty cheap (see here http://www.hobbycity.com/hobbycity/s...28eq:_70-40%29 ) I don't know alot about them but I would asume that you could run this motor well below capacity increase duty cycle.

[vlmarshall]

I've wanted to do this for quite a while... but the speed controller issue holds me back. There are plenty of excellent ESCs available, bit I want computer control of speed and direction.

[Vermiculite]

Somebody my be able to correct me but since a servo tester can be used to drive an esc, maybe a pc servo motor controller could work. These might be options http://www.pc-control.co.uk/howto_servo.htm or http://www.rentron.com/SerialServo.htm

I am sure there are people already doing it who could share.

[japroach]

I've wanted to do this for quite a while... but the speed controller issue holds me back. There are plenty of excellent ESCs available, bit I want computer control of speed and direction.

Speed control in one direction should be straightforward. We would take the spindle PWM signal from mach3/EMC, feed it into a microcontroller, and output the standard 1-2ms ESC input signal.

For reversing, we would add another output from mach3 (CCW relay output), and connect it to the micro as well. In reverse, the ESC signal is 1-1.5ms, and forward 1.5-2ms (or whatever the ESC is calibrated for).

Preferably the ESC would be:
higher voltage (if using that 48V motor)
reverse capable (without a special command sequence).

[japroach]

Here is a list of full reverse ESC's I found:

Hobby King Brushless Car ESC 100A - $38
- 17V
- some complaints of cutting out in the comments
- appears to have a simple reversing mode (if the manual someone linked to is accurate)

Turnigy Brushless ESC 60A w/ Reverse prog. (v2.2) - $43
- 12V
- I believe special procedure for reverse (brought to full brake, then neutral, then reverse again). Don't think this is an issue, just more work.

Seaking 60A V2 - $38
- 24V
- water cooled, so not suitable without modification

XERUN-60A-SD (V2.0) - $80
-12V


The hobby king 100A looks ok. 12V PC supply seems appropriate unless using one of the "monster" outrunners, which are in the 100kv range.

Can anyone recommend a better ESC (it doesn't have to have reverse)? Or a cheap test motor?

[Vermiculite]

Some stuff I already had but I bought some more toys to have a play with, and they arrived yesterday. My power supply amps is limiting but as far as I know should be fine for a milling machine that runs well with a 1/4hp motor. Started looking into these when I thought my taig spindle motor was on the way out as it was making a clicking noise. It ended up the grub screw on the pulley had come loose. I have no experience with this type of motor so it will be a learning curve (hopefully not too costly). If I get time I will hook them up later.

Here is what I have
-24v 15A switch mode power supply
-(ESC) Hobbyking SS Series 90-100A ESC Cells: 2-7S Li Po Max Current: 90A No BEC
-(ESC) 50A Brushless ESC FLBL50A (no backward) Input Voltage: 50A: 2-7S LiPo
-(motor) TURNIGY 63-74 200kv Brushless Outrunner 10~36V Kv : 200 rpm/V Shaft diameter : 10mm Weight : 900g
-(motor) Hobbymate HB2835-H 3800KV Maximum current: 37A Battery cells: 3S Perfect for 450 RC helicopters
-(motor) TURNIGY 50-65C 320kv : 14.8V-29.6V Current capacity : 60A/60s Max Power: 1200W Shaft diameter : 8mm / 0.31in
-Esky servo driver
-TURNIGY Servo driver
-TURNIGY 5-7.5A (8-42v) HV UBEC

I included the obligatory giant outrunner in the hand photo.

[awetmore]

Is your goal with this to get a higher RPM motor, or a lighter but just as powerful motor, or something else?

Have you done the conversions to figure out what the HP rating is on these motors?

alex

[Vermiculite]

Is your goal with this to get a higher RPM motor, or a lighter but just as powerful motor, or something else?

The standard motor is 60hz which is a problem for me in Australia. Treadmill motors don’t seem to be as prevalent here either. Most other people seem to be using outrunners for pcb milling but I want to know if these motors are suitable replacements for the Taig mill. I mostly mill aluminium and from what I have seen these motors should definitely have the power, duty cycle could be the problem. They also have the advantage of being variable speed which means no more belt changing.

I hooked the two larger motors up and they ran without anything exploding, simple test with no load. Here is the vid if anyone is interested. Nothing fancy just seeing if they would run ok. Need to test rpm, current and heat. I ran the larger motor for a couple of minutes and it was warm to touch (a fan maybe needed).

Turnigy 50 65
[nomedia="http://www.youtube.com/watch?v=LxBICGtm4GQ"]YouTube- turnigy 50 65.mp4[/nomedia]

turnigy 63 74
[nomedia="http://www.youtube.com/watch?v=Zwyx-8oO0S0"]YouTube- turnigy 63 74.mp4[/nomedia]

[japroach]

Some stuff I already had but I bought some more toys to have a play with, and they arrived yesterday. My power supply amps is limiting but as far as I know should be fine for a milling machine that runs well with a 1/4hp motor. Started looking into these when I thought my taig spindle motor was on the way out as it was making a clicking noise. It ended up the grub screw on the pulley had come loose. I have no experience with this type of motor so it will be a learning curve (hopefully not too costly). If I get time I will hook them up later.

Here is what I have
-24v 15A switch mode power supply
-(ESC) Hobbyking SS Series 90-100A ESC Cells: 2-7S Li Po Max Current: 90A No BEC
-(ESC) 50A Brushless ESC FLBL50A (no backward) Input Voltage: 50A: 2-7S LiPo
-(motor) TURNIGY 63-74 200kv Brushless Outrunner 10~36V Kv : 200 rpm/V Shaft diameter : 10mm Weight : 900g
-(motor) Hobbymate HB2835-H 3800KV Maximum current: 37A Battery cells: 3S Perfect for 450 RC helicopters
-(motor) TURNIGY 50-65C 320kv : 14.8V-29.6V Current capacity : 60A/60s Max Power: 1200W Shaft diameter : 8mm / 0.31in
-Esky servo driver
-TURNIGY Servo driver
-TURNIGY 5-7.5A (8-42v) HV UBEC

I included the obligatory giant outrunner in the hand photo.

Nice, I ordered the same smaller motor and a cheap esc with governor to see if its of any use. Although if its controlled via the PC, its easy enough to run a spindle encoder for feedback.

Is your goal with this to get a higher RPM motor, or a lighter but just as powerful motor, or something else?

Have you done the conversions to figure out what the HP rating is on these motors?

alex

The larger motor is rated at 3,200W, the smaller 1200W. If this is input power, we need to take another 20% off (lets say, it could be much better) for efficiency. Divide that result by 746W/HP and we get 3.4HP.
This is a bit unrealistic as some are destroying their motors if they run 3kW. So lets be safe and take ~1/3rd of that with forced air cooling as a practical maximum?

If you want to push it, the magnets should be re-glued. Also bearings and misc hardware, should probably be replaced.

[Vermiculite]

Nice, I ordered the same smaller motor and a cheap esc with governor to see if its of any use. Although if its controlled via the PC, its easy enough to run a spindle encoder for feedback.

I have no experience with spindle encoders but it doesn't look too difficult.

I had a bit of time yesterday so I made up a motor mount. The pulleys I have take an 8mm shaft so I had to bore a timing pulley to fit the taig spindle and wasn't quite aligned so I will try again. I fitted the 50-65 motor and everything went together ok though I will need to add another hole in the aluminium bar that attaches to the side of the spindle as the lower t-nut is now too low. I will probably end up using the larger motor but i need to get a pulley for it.