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baldysm
08-02-2011, 02:28 PM
I am looking at buying a high speed spindle for my mill.

http://cgi.ebay.com/All-New-12V-TB-650-Package-Deal-CNC-Router-Spindle-/170675955859?pt=LH_DefaultDomain_0&hash=item27bd146893

Is what I am looking at. Seems to get good reviews (and not in ebay as well).

25k rpm is too fast for some of what I do.

I talked to Wolfgang and he has a speed control for $135, and I'm thinking I can do better, but my knowledge of motors and electronics isn't up to the task. Based on his comments, it works, but it's not ideal and needs some refining.

What options do I have for a variable speed power supply? The motor is 12v and provides 200 watts cutting power.

Any advice for the electrically challenged?

aboard_epsilon
08-02-2011, 02:50 PM
as usual ..i may be wrong ..everyone can shout me down and i wont bark back ..some variable speed devices work in a way ..that the motor will be still be using 200 watts but turning slower .. with a 25,000 rpm motor..you better have good cooling, if that's the case ..

all the best.markj

JoeFin
08-02-2011, 02:57 PM
Wish Hurco made upgrade kits for their spindles as well. Newer more advanced bearings and 50% more Hp would make a world of difference from the 4000 rpm and 2 Hp

TGTool
08-02-2011, 03:17 PM
IIRC it's the PWM speed controls that will give you better performance at partial speed on those universal motors.

ikdor
08-02-2011, 03:31 PM
If you get a speed controller plus a servo tester from an RC shop, you should be able to control the speed for peanuts.

Igor

MaxHeadRoom
08-02-2011, 03:34 PM
You may be better off getting a high quality router, They have universal motors but there is a guy on the CncZone manufacturing speed controller for Universal routers that has rpm feed back control and rpm display.
So far it has good feedback.
I got one on the initial introductory price of $100.00.
Called SuperPID.
One running off of 12DC does not seem alot of range for precise control, also without feedback you get speed fluctuation with load.
Max.

macona
08-02-2011, 04:20 PM
I would buy one of the chinese water cooled spindles before I bought that thing.

Black_Moons
08-02-2011, 05:00 PM
I allways kinda liked the idea of speed multiplyer attachments.

darryl
08-02-2011, 05:29 PM
Seems to me that as long as you're going to use a brush-type motor, and you have standard power available, you'd be better off using a higher voltage motor. Nothing wrong with a permanent magnet motor- lately I've been looking at brushless types and considering what type of speed control can be integrated into the commutation controller. The brushless types are quite suited to high speed and long life, and since they are mostly using the more powerful magnet types, they are very powerful for their size.

The trick would be to find one that is wound to run from 160vdc, which is simple rectified 110vac. The downside is that a controller is required, and that can often cost as much as, or outweigh the cost of the motor. But then the upside is that since you'd be adding a speed controller anyway, the cost of that would at least partly recovered in not needing the controller- provided that a suitable circuit could be found that can do the commutation and speed control in one unit, using a potentiometer. These little motors, being permanent magnet, would not run directly from a typical 3 ph source, although they are 3 ph motors.

These are the two main deterrents to using this type of motor in the home shop, running from typical available power which is ac- single phase 110 or 220, etc. A suitable controller is required, and a suitably wound motor is required. Other than that, they are suited for high speed operation with smoothness and long life, so could be ideal for high speed spindles.

macona
08-02-2011, 06:32 PM
I allways kinda liked the idea of speed multiplyer attachments.

Problem with those (I have one) is they have a pretty short duty cycle. They get hot pretty fast.

Tormach came out with one that will fit their machines as well as any machine with a 3-3/8" quill. It is belt driven. Pretty cheap, about $900. No real specs on it like runout though which is pretty critical for tiny endmills.

http://www.tormach.com/Product_PCNC_acc_spindle.html

baldysm
08-02-2011, 06:44 PM
Knew you guys would get my head spinning. :)

I'm totally open to some other spindle. I have a Sherline CNC mill that needs a better spindle for wax, brass and the occasional engraving on titanium.

The motor is a 540 motor, which apparently is used for RC cars. Can't be too hard to control the speed on them. I am kinda concerned about power and reliability.

The Sherline spindle has a max speed of about 3000 RPM. They offer what is essentially a pencil grinder as a higher speed spindle, but it's 50,000 RPM IIRC, and there some runout issues. It helps, but it's not great.

I also have the 10,000 RPM spindle from Sherline, and that has some over heating issues, especially when run for extended periods, like I tend to do.

I'm always at max speed on the Sherline spindle. Unless I'm using an edge finder, I'm almost always using a 1/8" shank tool and power isn't much of a concern

I will not go with a Chinese piece of **** spindle. I'm American, and advertise my products as made in the USA, and I do my best to buy American and employ Americans. Unless I have no other reasonable choice, I practice what I preach.

Unless someone has a better option, I need a PWM speed controller and an adapter for 110v?

darryl
08-02-2011, 07:45 PM
If you want to run that 12v motor at about 20 amps (200 + watts) then you either need a fairly robust power supply (for the current capability) or a lead-acid battery with trickle charger. There are a few speed control circuits based on the 555 ic that will easily do the job. You'll need a capable output device, preferably a mosfet, a potentiometer, the ic itself, some support components such as resistors and capacitors, a bit of pc board- the rest is wire, suitable enclosure, terminals-

This is basically a pwm circuit. You'll have some choices, one is the base frequency to use. It would help if you can make it adjustable, since it can make the difference in the noise level from the motor. Another choice would be the minimum speed you're able to set, although this probably won't be important for running a high speed spindle.

If you'd be willing to tackle this minimal electronic project, just look up motor speed control circuits using the 555 timer ic. I've looked up a few of them in the past and they are out there.

Because that is a 12v motor, and the ic will run fine on 12v, you just run the whole thing from the battery and rely on the trickle charger to keep it up. I think I've mentioned this before, but you could check into those power failure lighting units. Some are 6 volt, some are 12. They already have the charge maintenance circuit and the battery- you might consider it a bonus that they will also act as a power failure light :) Just mount a terminal block on the outside of it, run a pair of wires from the battery directly to that, then run some wires to your control box which you mount conveniently near the machine.

macona
08-02-2011, 07:58 PM
I will not go with a Chinese piece of **** spindle. I'm American,

Well, you might be getting an American piece of **** spindle instead. You know nothing about the design of the spindle.

john b
08-03-2011, 12:06 AM
Will this work 0-90vdc https://www.surpluscenter.com/item.asp?item=11-2269&catname=electric john b.

form_change
08-03-2011, 07:56 AM
Have you thought about using an air motor? Might be easier than trying to get electrons to behave themselves.

Michael

macona
08-03-2011, 12:21 PM
Have you thought about using an air motor? Might be easier than trying to get electrons to behave themselves.

Michael

I have tried that. Works, but unless you have a big compressor it is not very appealing. I had a 5hp compressor running continuously when I used mine.

gwilson
08-03-2011, 12:29 PM
Agreed,Macona. Air powered tools waste so much energy. It takes a BIG compressor to run a fairly small hand piece.

I have a 1/10 H.P. Dumore hand grinder I am going to use as a high speed spindle. Will make a thick aluminum bracket to attach it to the quill of my vertical mill. It runs 10,000 RPM. I have a router speed control that can slow it if needed.

Since this spindle will only be used with very small endmills(under 1/16"),it should have plenty of power.

I missed out on a clever little cast iron speed increaser that was on Ebay. You put a 3" pulley into the quill. The attachment clamped around the spindle,and had a 1" pulley on its spindle. A belt was added to connect them.

Probably quicker to mount the Dumore powered spindle I am going to make,though.

TRX
06-02-2012, 11:22 AM
I would buy one of the chinese water cooled spindles before I bought that thing.

I've been looking at those. The general spec seems to be 220-250V, 400Hz. The motors are rated at 800 watts.

Maybe I'm looking in the wrong places, but 400Hz power supplies in the 800 watt range (shouldn't it be closer to 1500 watts to allow for motor efficiency loss?) cost a lot more than the danged spindle does.

lakeside53
06-02-2012, 12:21 PM
I agree with Gwilson. Dumore Tool Post grinders will make great high speed spindles. They are a precision sipndle, and built for high speed. For $200-500 you can buy them on Ebay, and some (like mine for $300) are pristine.

lakeside53
06-02-2012, 12:22 PM
I've been looking at those. The general spec seems to be 220-250V, 400Hz. The motors are rated at 800 watts.

Maybe I'm looking in the wrong places, but 400Hz power supplies in the 800 watt range (shouldn't it be closer to 1500 watts to allow for motor efficiency loss?) cost a lot more than the danged spindle does.


They are 3 phase. You use a VFD - even the cheap Hitachi's do 0-400hz.

TRX
06-02-2012, 04:00 PM
3-phase! A VFD is cheap enough, but none of the ads I looked at (one up in another tab right now) says a word about 3-phase!