Syil X3 CNC Spindle Failed

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

Mike

Hi Mike have you thought of replacing the spindle and controler there are many spindles on the web with controler included.

David

The short answer is no.

A DC motor with brushes runs on (you've guessed it) DC. Motor speed is proportional to the applied DC voltage.

A brushless DC motor requires switched (AC) voltages across the colis. Essentially the switched waveforms replace the mechanical commutator with electronic switches. Motor speed is directly related to the switching rate, unlike an induction motor where the speed is load dependent to a small degree. Brushless DC motors can be run without position sensors, but the simpler, and hence cheaper, method is to use Hall effect devices on the rotor to determine position.

A VFD outputs a PWM signal where the width of each pulse changes from pulse to pulse. The output emulates a sine wave. The induction motor speed is set by the frequency of the sine wave less a few percent depending upon load. Passing the VFD output through a diode would result in a waveform similar to the input - definitely not DC.

The longer answer is that you need to use a controller designed for the type of motor you want to drive. To do otherwise will result in failure and possibly the release of the magic smoke.

Andrew

Edited By Andrew Johnston on 01/09/2019 21:34:11

I assume you mean 200V, not 20 V, as you also say you couldn't find a dc controller giving more than 80V?

Is it really a brushless motor? If it's a brush motor (and a lot of CNC machines use these, such as the Denfords), then look at KB Electronics controllers. I have one on my little Novamill and it works very well with the brushed motor. KBE drives are distributed by Axis Controls in the UK.

Thanks for the advise, I have found this controller

**LINK**

Do you think it would work?

Mike

Possibly. It claims to run over a voltage range of 24-48V which might work for a 20V motor. But like John I wonder about the motor voltage, it seems rather low and hence currents will need to be large for any significant power..

To provide a definitive answer we need more detailed technical information about the motor and controller.

Andrew

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

Thanks

Mike

Edited By Mike Palmer 1 on 12/09/2019 12:07:11

Edited By Mike Palmer 1 on 12/09/2019 12:07:57

I know nothing about a Syil X3 CNC milling machine but are you saying it is fitted with a 230VDC brushless motor?

A brushless motor only becomes a 'DC' motor when it is combined with electronics, the motor itself is driven by several windings and they need the correct AC type waveform to cause the rotation.

The diver you have bought might be entirely suitable for the motor you have but the wiring between the two must be correct, most likely the fact that it is not running now is either a wiring difference or some other incompatibility.

What details are shown on the motor rating plate?

Ian P

Ian

Thanks for reply here is link to motor details

**LINK**

Mike

Mike

That does not give any details that would allow anyone to choose or wire up a controller.

Ian P

If that is the same motor on your Syil machine, then why not buy the controller that Arc sell.

Gray

The controller Arc sell will only operate the spindle manually, as it’s a CNC machine it is ideal the machine controller runs the spindle, speed and direction.

The driver I have will do this if I can get it going!!!

I am into it for £300, if I get nowhere with new driver, I might have to consider forking out another £250 for the Arc board and run the spindle manually?

Mike

What voltage have you got going into the controller, from what I can see it does not take 240V unless that is a typo on the second image.

'DC Brushless motors' are fed from a switched DC supply rather than a true AC supply.

So a typical VFD outputs three sine waves (or at least approximations of them using PWM):

A BLDC controller outputs three differently phased square waves, using pulse width modulation to control the power:

I see that the motors supplied by the company the controler came from are 24. 36 and 48V they don't do 240V brushless motors as far as I can see

Neil

Thank you for you input, but I am not an electrical engineer these charts mean not a lot to me. I can understand conect terminal U to Hall Ha and the like.

Jason

Same as above but looking at the Arc spares for SX3 motor states 230V DC all I can do is follow what others tell me!!

Mike

Neil, in my reply I simplified the waveform required by saying the motor needed an AC 'type' supply, probably not the best word to use but I was trying to say that the motor itself is not a DC motor, it needs external commutation. The waveform fed to each winding is created from a DC bus, but then that probably started off as an AC waveform (the mains).

Motor manufacturers might describe them as Brushless DC but its mostly just to put them in a category for sales or convenience purposes.

I think that unless I had the full motor details I would bite the bullet and use the makers controller. Most likely it might be modifiable to accept external control inputs (harder if the supplier does not give any information though).

Ian P

Nobody told you to get that controller, Andrew queried it after you posted the link and I'm also questioning whether the controller you have bought will work on the motor you have as it may well be for 48V. Have you asked the supplier?

Jason

The controller I have bought is not the same one I showed in an earlier post, as got no reply from my enquiry.

Have you looked at the Arc motor spec? if so please tell me what you think the voltage is?

There are many 36, 48 60 v DC Brushless Motor controllers on the market, but as stated earlier I was trying to find one with 230V rating .

Mike

I would say the SX3 one from ARC is 230VDC

But best to look at what is on the side of your motor as Syil may have sourced parts from elsewhere, board could be different too as some of the Sieg boards are exclusive to them even if made by the same supplier.

Do you know for sure that it is not the motor that is at fault?