Model Engine Maker

Help! => Machines, Tools and Fixtures => Topic started by: mikemill on September 01, 2019, 12:18:25 PM

Title: Syil X3 CNC Mill Spindle
Post by: mikemill on September 01, 2019, 12:18:25 PM
I have a Syil X3 CNC milling machine, I think I must have been one of the first to buy theses machines some 9 years ago, they were cursed with problems most being electronics, but managed to solve the issues as they came up.
However, the spindle control board has finally given up the ghost all other stepper motors work well. Even if I could find a replacement board my faith in them has long since gone. I would like advice on controlling the spindle which is powered by a 20V DC brushless motor. Is it possible to use a VFD and change the output via a rectifier to DC?
I have looked for DC motor controllers but the highest voltage I could find was 80V
Any ideas would be appreciated

Title: Re: Syil X3 CNC Mill Spindle
Post by: Muzzer on September 01, 2019, 03:54:27 PM
In simple terms, no. The output from a VFD is actually a PWM voltage with a constant peak voltage (around 340Vdc with 240Vac input), an average voltage that is generally proportional to the set speed and a frequency that is porportional to motor speed. A DC brushless motor drive needs to know the motor position, so it's not possible to use a std VFD - with that motor you are pretty much obliged to stick with a compatible brushless driver board.

Can't you fit an induction motor in place of the brushless motor? Then you could use a VFD. There must be loads of people out there who have had the same thoughts.
Title: Re: Syil X3 CNC Mill Spindle
Post by: Jasonb on September 01, 2019, 04:34:09 PM
For the wattage they are quite a bit smaller than the average induction motor so you may have to mount one outside of the head and would you be able to get the revs, if like the KX3 then that runs to 5000rpm with almost 1:1 toothed belts

Thanks for the explanation of the way the motor works, I now know why there are two sets of wires to it, similar smaller wattage motor from the SX2.7

Title: Re: Syil X3 CNC Mill Spindle
Post by: Muzzer on September 01, 2019, 09:54:38 PM
Brushless DC motors are usually driven with a simple, flat waveform ("6-step" or "trapezoidal") and the commutation is usually done with 3 Hall effect sensors, which are buried in the motor. The drive scheme is pretty simple but the performance is not as good as that of a sinusoidally driven motor such as an induction ("asynchronous") or permanent magnet ("brushless AC") motor and the cogging torque and noise is usually greater.
With a VFD, you can drive an induction machine above base speed, notwithstanding the mechanical (burst) speed limit. Alternatively, there are induction motors designed for high speed operation - my larger machine has a motor rated for up to 6500rpm. Another approach would be to run a lower motor speed with a larger pulley.
Title: Re: Syil X3 CNC Mill Spindle
Post by: RonGinger on September 01, 2019, 10:20:02 PM
I have been struggling with the DC motor that came on my Grizzley G0704 mill. The control blew some time ago and I have fitted a couple motors but have not been happy with any of them. I tried an induction motor and VFD but it was just to big and bothered me on top of the mill.

I recently found a brushless DC motor and control on Amazon sold as replacement for commercial sewing machines. It was under $100 for a 500 watt motor. I have not installed it yet so I  can not offer any results, but it looks like a nice motor.
Title: Re: Syil X3 CNC Mill Spindle
Post by: mikemill on September 02, 2019, 09:36:10 AM
Thanks for the suggestions, I have found this controller

Do you think it would do the job?

I also concidered attataching a seperate motor fitted to the side of the head and controlling it via a VFD but cound not find one small enough


Title: Re: Syil X3 CNC Mill Spindle
Post by: mikemill on September 12, 2019, 11:55:51 AM
I have found a motor driver suitable for the 230v DC brushless motor.
I connected power in to windings also hall sensors, and set various switches but no movement from spindle.
I have attached specs and notes, any help would be appreciated

Title: Re: Syil X3 CNC Mill Spindle
Post by: Allen Smithee on September 12, 2019, 12:53:38 PM
Be aware that there are two kinds of brushless DC motors - "sensored" and "sensorless". The sensored ones have hall-effect sensors built into the motor to sense the rotor position so that the controller and commutate the windings synchronously. The sensorless ones have circuits that detect the back-emf "kick" as the magnets pass the windings and use this ti time the commutation "asynchronously". Speed is usually controlled by commutation timing on sensored motors and by PWM on the sensorless ones, so they need very different kinds of controller.

Sensorless motors and controllers are smaller, lighter and cheaper, but sensored motors and controllers can be configured to give much greater low-speed torque and they are generally smoother (less cogging, less virbration) with lower electrical and physical noise.

Title: Re: Syil X3 CNC Mill Spindle
Post by: Muzzer on September 12, 2019, 02:33:55 PM
Have you connected up the alarm output to see if it is objecting to anything? I see one of the error states is caused by incorrect Hall signal.

On the face of it, this appears to be suitable for driving a brushless motor with Hall sensors. There is always the possibility that your Hall signals may be inverted relative to what the drive is expecting. Perhaps if you look at the datasheet for the motors that are sold alongside these drives, you might be able to figure out what is required.

Does the supplier have any other data apart from a simple GA drawing, eg a user manual? Or do they even offer any sort of technical support?
Title: Re: Syil X3 CNC Mill Spindle
Post by: Admiral_dk on September 12, 2019, 05:19:20 PM
It should be obvious, but .... we all overlook details from time to time ....

So have you connected an E-Stop safety switch between the EN and SGND pins ? - it should short them when not engaged, to enable running of the motor.

Do you have either a speed voltage on the SV input or a PWM speed signal on the SVP input ? - a lot of controllers expect zero voltage on the Analog Speed input to equal Zero RPM.

Best wishes

Title: Re: Syil X3 CNC Mill Spindle
Post by: mikemill on September 14, 2019, 05:29:16 PM
I contacted the manufacture and they came up with a wiring solution totally different to the notes on their spec notes, and hey ho the bugger WORKS, much to my relief.

With hindsight I should have done that in the first place, rather than annoying MEM
members, so thanks to those who replied with suggestions.

As I said I am out of my depth when it comes to theory of electronics, but to get the mill working who in my part of the world is going to take on a task like this? Answer NO ONE.