Cncst4060

**Doddy** · 11-09-2020

I cannot recommend using that new spindle with the VFD that you have. The limited frequency range I can handle (it just means a lower maximum RPM - 18k RPM), but the lower power drive means that you carry significant risk of damaging the VFD.

There are settable parameters on the VFD that allow you to set motor current - but my feeling is that these are used to trigger the over-current protection, not to limit the motor current.

The problem now is that you've sourced the spindle - the supplier may be reluctant to support any subsequent change.

...unless anyone else knows more about the VFD motor-current settings?

**petesos** · 11-09-2020

Understood Doddy
What surprises me as you have so rightly pointed out the capacity of this VFD is rated at 300Hz yet the spindle that came with the machine is rated at 400Hz.
Why would the company send a boxed machine ( brand new ) with a vfd that is not even rated to handle the spindle they put in the box .

So i must ask what sort of price is a VFD box that would handle this 1.5 spindal

Would the 100Hz short fall in the vfd make much of a difference to the spindle.

So am now thinking shouuld i go and buy another vfd box to run this new spindle

**Doddy** · 11-09-2020

The frequency is not much of an issue - the spindle is typically a 2-pole motor, which basically means each complete 3-phase cycle1 = 1 revolution. So at 300Hz (300 cycles/sec) = 300 revs/sec. 60 secs in a minute = 18000 revs/min. If you drive at 400Hz, 24000 revs/min. Yes, you can drive the motor at 18000 rpm or 300Hz - that works.

With the original spindle - the VFD is rated correctly for the 800W spindle (or thereabouts).

The problem is the new spindle is 1500W, which is likely to damage the VFD. That you can't spin the spindle as quickly as its designed is another issue, but wouldn't damage either spindle or VFD. Why would the supplier provide that VFD?, you'd have to ask them, but usual suspect would be cost.

**petesos** · 11-09-2020

Can i ask you Doddy
Am i just as well buying a new 1.5 vfd box and running the spindle from that , separate from mach3 as i need to move on and start machining the urethane bushes and sort out the cost with the supplier later , i see you can get the 1.5kw vfd box for 50 quid or so

Sorry only just seen this post

**Doddy** · 11-09-2020

You ask what sort of price for a suitable VFD - that's very much down to what you want to pay. You can get a quality VFD for - I don't know, several hundred quid. You can get a cheap one for fifty quid, that the advert caveats for low-loads only (which worries me). The usual suspect often used is a HuanYang VFD - not the best, but swamped the market with an affordable solution that many of us bought (the market is currently swamped with cheaper versions). Caution is needed with the HuanYangs as the Chinese are known to knock off their own knock-offs, and the suggestion is there are counterfeits out there. For that reason I'm not going to link any because I don't want the responsibility of pointing you at something that could be wrong.

But, to try to be helpful, the basic spec you're looking for is:-

220VAC single phase input, 50Hz
220VAC three phase output, 0-400Hz
1.5kW (higher is okay, lower is not)

**petesos** · 11-09-2020

Originally Posted by Doddy

You ask what sort of price for a suitable VFD - that's very much down to what you want to pay. You can get a quality VFD for - I don't know, several hundred quid. You can get a cheap one for fifty quid, that the advert caveats for low-loads only (which worries me). The usual suspect often used is a HuanYang VFD - not the best, but swamped the market with an affordable solution that many of us bought (the market is currently swamped with cheaper versions). Caution is needed with the HuanYangs as the Chinese are known to knock off their own knock-offs, and the suggestion is there are counterfeits out there. For that reason I'm not going to link any because I don't want the responsibility of pointing you at something that could be wrong.

But, to try to be helpful, the basic spec you're looking for is:-

220VAC single phase input, 50Hz
220VAC three phase output, 0-400Hz
1.5kW (higher is okay, lower is not)

Thank you Doddy
That is plane and simple to me and understand your concern about the cheap vfd .
now to start thinking about this

**Doddy** · 11-09-2020

Pete, sorry, this appears to have been a less than ideal introduction to CNC.

A word of caution, particularly buying a spindle separately to a VFD, you will likely need to configure the VFD for the spindle - that's the next hurdle. I could suggest contacting the spindle supplier to ask if they have a suitable ready-configured VFD that is affordable.

Just a thought.

**petesos** · 14-09-2020

Originally Posted by Doddy

Pete, sorry, this appears to have been a less than ideal introduction to CNC.

A word of caution, particularly buying a spindle separately to a VFD, you will likely need to configure the VFD for the spindle - that's the next hurdle. I could suggest contacting the spindle supplier to ask if they have a suitable ready-configured VFD that is affordable.

Just a thought.

Hi Doddy
Just seen this ,,,bugger .never mind onwards and upwards.
Here is a few photos of the VFD that i purchased today , I bought this one as i didn't want to go and spend a load of money on a real good one yet as i would like to see if this set up works first and if it is viable .
The wire for the spindle was marked from 1 to 4 to start with so i soldered Wire 1 to pin 1 . Wire 2 to pin 2 and so on ( this was on the socket for the spindle.
And using my tester on the connectivity setting i tested each wire and connected them as follows

I connected the No 1 wire to the V
No 2 wire to the W
No 3 wire to the U

Then i pressed run and turned up the speed and at H 16 an error message came up.
any ideas please

**JAZZCNC** · 14-09-2020

Did you set the VFD parameters to match your spindle ie: Voltage, current, freq, etc. If not this could be your problem as the defaults may not match your spindle.
I don't know this VFD and don't have a manual to see the fault codes but the usual suspects for fault codes on startup or slowdown is too fast Acceleration or deacceleration settings.

If you have them set to accelerate too quickly and you call for a high RPM then the VFD try's to get to speed in the set time by dumping high amounts of current into the spindle and this trips a Fault because it pushes higher than the set parameter. Likewise if you haven't setup the VFD parameters and it's on the default which is often set low the same will happen.