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..?

[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?