Brake resistor

[odinnb]

Hello

I am having a problem with a Kuka KR 150 with a Linear axis and a krc1 controller.

The robot was functioning well. Then we were moving it in house to another location. When starting it up after that, the controller started up normally, but as soon as i held down the [Dead man switch] the circuit beaker for the robot tripped. After some attempts the electricians realized that they had put a  wrong circuit beaker for the robot, causing it to trip. At the same time they realized that the phase order was wrong.
This was corrected and the right circuit beaker was installed. Now when starting the robot and pushing the [Dead man switch] and tried to move the linear axis I got "brake resistor on for too long".
After going through this forum I found a post on a similar topic and realized that the Brake resistor for the linear Axis was broken and showed no resistance. I had a company build a new one, and installed it. Now the error "brake resistor on for too long" is still there and as soon as i push the [Dead man switch] I can feel the resistor starting to heat up. Like it is in continuous braking. I have the feeling that some relay is stuck (faulty).
In the post I found on this forum somebody mentioned that the resistor is turned on by a IGBT (Insulated gate bipolar transistor). I do not have any electronic drawings for these modules.

The question: How can I debug this? Should I uninstall the Power supply module PM0--600 and the Single--axis power module PM1--600/16 and open them and do a visual check....? Any help is appreciated.
Best regards

Odinn

[SkyeFire]

This is definitely incorrect behavior.  The braking resistor should only ever flow current during the dynamic braking phase of a motion -- the resistor converts the inertia of high-speed motion into heat in order to dissipate excess energy.  If the resistor flows current just from the deadman/enable being closed, something is definitely wrong. 
The problem is, this usually involves replacing the entire PM6 module.  I've never seen an electrical diagram that shows the resistor circuit in sufficient detail to attempt repairing this problem at the component level, but there are other posters with more experience in the KRC1 controllers than myself. 

[odinnb]

Thank you SkyeFire!!!
I hope someone here in the forum knows a way to solve this!!!
I will be unplugging the modules on monday to do a visual check of components.

I cross my fingers until then

Best ...

Odinn

[odinnb]

I have solved the problem...After I took the power module (PM0-600) for the linear axis apart I soon saw that the most likely part to be broken was the "Three Phase Rectifier Bridge with IGBT and Fast Recovery Diode for Braking System" I ordered a new VUB 71-16 NO1 (Cost 100$) and put it in and everything workes fine now.
Hope this helps someone one day :-)
Odinn