Testing The VFD, Break Resistor and Wiring to AXBBE

[Phil Mayor]

The supplier has just got back to me and suggested increasing the Break Resistor to a 1500w 75ohm type, but from my understanding a 75ohm would take even longerr to stop than my 1000w 60ohm one..?

[voyager1972]

I am following this post with interest as i am also in the middle of an upgrade to an atc spindle which i have mounted and have running from the potentiometer , i plan on using the manual tool change butoon until i get my head around the auto tool change setup ,i also have a braking mechanism which was part of the original setup with the old spindle .i love having a go at these things myself but i am finding it difficult to get information online ,so hopefully i can get some good advice on the forum , i am running uccnc with the uc300eth-5lpt and ucbb.

[Phil Mayor]

Hey Voyager,

I'm like you and also love having a go myself, I hope you can get some advice/info that will help your build, although I doubt it will be from me Muzzer has been a great help so far and he has helped me get to the stage I'm at and understand how I got there, but unfortunately I still can't get past the final hurdle - I must have read the manual 4 or 5 times but I can't see any other Parameter that relates to Breaking, so I just don't know why it's not working as it should... I have thought maybe it's the VFD itself but it is breaking, just not enough, which then leads me to think it's a parameter that just needs tweaking....

[voyager1972]

the braking mechanism was setup on my old vfd , i will hook it up and go through the settings and see what i can find on the braking side , i am stuck with the manual tool change button , i want to connect it with two solenoids in line ,one connected to the button the other connected so that it is disabled when the spindle is running , i just dont know how to go about it ,i would like it to be safe ,i dont want a tool ejected during a cut , i upgraded my machine 2 years ago from a chinese controller to uccnc ,it took me a while but i got there in the end , i am not into the electrical side of things but i really enjoyed the whole process. then i purchased an atc spindle and vfd and that is where im at now.

[Phil Mayor]

Looks like a nice Spindle that mate, yeah any help would be appreciated thanks!! I know what you mean, I have attached a diagram that has come with my Spindle, it sounds like exactly what your describing, weather you've already got this or it helps I don't know...obviously it's a different Spindle but the same principals, I could send the whole document if you think it helps..??



Also just remembered I watched a YouTube a few weeks back and Clogh42 has a video (ATC Part 10, interlock and E-stop wiring) similar to what you want and he explains it well, worth a watch it's only 30mins

[Muzzer]

The supplier has just got back to me and suggested increasing the Break Resistor to a 1500w 75ohm type, but from my understanding a 75ohm would take even longerr to stop than my 1000w 60ohm one..?

Haha yes, that wouldn't help. Did you lower the threshold voltage (parameter 01_31) to 600V (not critical but probably helps)? Brake utilisation rate (01_30) probably needs to be 100% for max effect. You might also need to set stop mode (01_07) to zero ie "decelerate stop" - it sounds as if you may have it set to 2 ie "DC braking".

One of the issues with Chinesium products is often the machine translated manuals causing issues like this. Ask me how I know!

[Phil Mayor]

Hi Muzzer,

Ok, so I've double-checked those settings and they are as above, I've also done more testing today... I'm beginning to wonder if the Braking Resistor terminals are even connected on the PCB Board - I tested the following

1) No Break Resistor attached to VFD, DC Brake off (01_07 - 0)
2) No Brake Resistor attached to VFD, DC Brake on (01_07 - 2)
3) Brake Resistor attached to VFD, DC off (01_07 - 0)
4) Brake Resistor attached to VFD, DC on (01_07 - 2)

1st test had a fault and the Spindle just free-wheeled to a stop after approx 2min 30seconds
2nd test stopped on 21 seconds +/- .5
3rd test stopped on 21 seconds +/- .5
4th test stopped on 21 seconds +/- .5

The internal built-in brake is slowing it down but isn't powerful enough to stop it quickly and for whatever reason the external Brake Resistor is having no effect I have checked the Break Resistor for resistance with my Multimeter and it's saying 60ohms so I can only assume it's ok... I would like to know is there a way to check the actual VFD with my Multimeter to see if the DC Brake wiring is even connected... I don't know where I would need to put the multimeter prongs to test or what setting to have it on, if you or anyone else knows that would be great.

Cheers,


Phil

[Muzzer]

If you trust yourself, you could put your voltmeter across the braking resistor and see if any voltage appears across it during decel.

As you say, some VFDs ship without the braking resistor circuit fitted.

What decel time is programmed?

[Phil Mayor]

I set the Decel time to 3.5s

Yeah I'll have a go... so, just to be clear,

Do I set Voltmeter to DC... I know it goes in as AC but then it gets converted at some point to DC, then back again to AC, is that right..?
and just put the Red on the DC+ or R+ Terminal that the Brake Resistor is attached to and the Black to the R- Terminal that the Brake Resistor is attached too?
and take the reading as I hit stop

[marky68]

Following you guys on here and this thread too, https://www.mycncuk.com/threads/1340...se-atc-spindle .

I've just started my conversion, mines a similiar spec to voyager1972. 6Kw HQD Atc spindle, ETH300 with UBB board & Uccnc controller...

Pity we're not all located close to each other..