[dcis77]

Hello Guys,

I am facing a problem with my Haas VF-2 Mill.

3 months ago, I had an alarm "DC Bus Shorted" on my screen, and I couldn't reset my machine. I could only reset this alarm by waiting for 20 minutes approximatelly. Then, everything ok.

Now, the alarm is permanent and does not dissapear at all by reseting.

What is happening?

Thank you in advance!

[DruMor]

On our VF-4 when it had a similar problem, it was the Vector Drive. At first, you could reset it after 5 minutes, then the time before the alarm would clear kept getting longer and longer. It eventually got to where it would take hours before it would clear. So we left the machine on and that worked until I had a brain fart and shut it off one day...it sat all weekend on and still wouldn't clear. Thats when we decided it was time to fix it

[wdomhart]

Try disconnecting the servo-amplifiers for the axes one at a time and see if the alarm goes away. One of your servo-amps might be bad. We'll see where we can go from there. Also, what's your control cabinet look like?

[dcis77]

Guys, a technician tried to "fix" the small green board inside the vector drive, but unfortunately two of the capacitors blow!!!!

[Donkey Hotey]

I don't know what he could have tried to 'fix' on any of those boards. There are three main parts to the Vector Drive:

• The spindle drive portion: this includes the large logic board and the three large IGBTs and one smaller IGBT connected to the spindle motor and the spindle brake resistor.
• The 24V DC power supply. The only purpose of this power supply is to run the logic portion of the spindle drive amplifier control board. It's pretty easy to identify because this is on its own board.
• The 320V DC power supply portion. This is made up of a large contactor (relay), a three-phase bridge rectifier (big black thing with three wires in and two wires out) and the smoothing capacitors. The capacitors connect in parallel with the 320V DC output lines and go to the 320V screw terminals on the connection rail.

The 320V portion shouldn't be too hard to diagnose. First, make sure the transformer is connected to the right taps so the power supply is getting the voltage it needs. Next is the bridge rectifier. That can be checked with a good diode checker while out of the machine. I doubt it's bad but, it COULD fail. Next would be those two big capacitors. If one or both of them shorted, that would cause the problem you're describing.


The bad news is that those are big capacitors and they aren't cheap. It's still cheaper than replacing a whole vector drive.

Also: IF YOU ARE NOT COMFORTABLE WORKING ON HIGH VOLTAGE ELECTRONICS, STAY AWAY FROM THAT STUFF. THE VOLTAGES ON THOSE SCREWS WILL KILL YOU.

There is a voltage indicator light on the vector drive. You need to make sure that light has gone out before working on it or voltage is still present (stored in the capacitors).

[woodtech]

vector drive is closed loop system.WITH POWER OFF FOR 30 min Ohm out motors and cables (1.3 to 1.5 ohms and open to ground ) spindle motor 6 or 8.6 ohms. measure the voltage between terminals 1 and 3 .should be 300vdc or more if not vector drive bad.if good problem with either the amplifier or regen load

[dcis77]

Thank you Greg for the information!

Thanks for your info woodtech too!

[haastec]

Guys, a technician tried to "fix" the small green board inside the vector drive, but unfortunately two of the capacitors blow!!!!

I am not sure where you are at with your repairs, but I would advise that you find a company that has experience repairing the Haas Vector Drive even if you have to ship to the US or buy a replacement from your dealer.

You will be both time and money ahead by doing the repair this way. I have heard to many stories about repairs taking months to get done correctly only to purchase a new drive from Haas. Granted, there are success stories out there also, but unless you have detailed knowledge about the type of components used inside the drive, you will struggle.

Either way, good luck on the repair!