Hello, Thank you for your time!
Here is the issue:
Appreciate any advice on the risks of armature failure, and likely failure mechanisms, when we eventually put it all back together and run it.
Is arcing through a cracked bar the main failure scenario to be worried about?
If 1 parallel bar is open circuit (or close to it), and the other 5 bars are sharing the increased load (20% increased current), are the I squared losses a worry for life of the armature?
If the failure scenario is one of the bars having high connection resistance, say 1 ohm in series with the 4700 micro-ohms, could I squared R losses at the 1ohm result in a failure?
Thanks
Here is the issue:
- Average segment to segment resistance is 780 micro-ohms.
- After a commutator skimm, one segment to segment resistance measurement was measured at 970 micro-ohms (rest all remained at 780 micro-ohms).
- Full load segment to segment voltage is 12V. Full load segment to segment current is 330A continuous.
- Each segment to segment armature circuit has 6 parallel bars (3 larger bars and 3 smaller bars).
- The bars are TIG welded to the riser.
- The segment to segment with a higher resistance has a parallel resistance consistent with one of the larger bars going open circuit, or close to open circuit.
- Unable to NDT to check for cracks.
- Load testing is not an option.
Appreciate any advice on the risks of armature failure, and likely failure mechanisms, when we eventually put it all back together and run it.
Is arcing through a cracked bar the main failure scenario to be worried about?
If 1 parallel bar is open circuit (or close to it), and the other 5 bars are sharing the increased load (20% increased current), are the I squared losses a worry for life of the armature?
If the failure scenario is one of the bars having high connection resistance, say 1 ohm in series with the 4700 micro-ohms, could I squared R losses at the 1ohm result in a failure?
Thanks