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Q&A Motor Controller - What might be the purpose of these resistors?

I'd guess surge resistance and redundancy, rather than power dissipation. Looks like 10 stages of 5x parallel 2k going left to right?? So that's 10x400 = 4k. Perhaps used for parallel damping the...

posted 3y ago by Pete W‭  ·  edited 3y ago by Pete W‭

Answer
#2: Post edited by user avatar Pete W‭ · 2021-08-17T00:06:35Z (about 3 years ago)
  • I'd guess surge resistance and redundancy, rather than power dissipation.
  • Looks like 10 stages of 5x parallel 2k going left to right?? So that's 10x400 = 4k. Perhaps used for parallel damping the DC link???? (the 6 subcircuits below would be the 3phase half bridges...). Presumably then the DC link would be prone to big inductive spikes (thus HV), as various diodes return to it.
  • If it were exclusively thermal / non-momentary power dissipation, I think the pads could have been made larger and/or more widely spread relative to the resistor package- not 100% sure this is always the case however.
  • I'd guess surge resistance and redundancy, rather than power dissipation.
  • Looks like 10 stages of 5x parallel 2k going left to right?? So that's 10x400 = 4k. Perhaps used for parallel damping the DC link???? (the 6 subcircuits below would be 3phase half bridges??). Presumably then the DC link would be prone to big inductive spikes (thus HV), as various diodes return to it.
  • If it were exclusively thermal / non-momentary power dissipation, I think the pads could have been made larger and/or more widely spread relative to the resistor package- not 100% sure this is always the case however.
#1: Initial revision by user avatar Pete W‭ · 2021-08-17T00:04:12Z (about 3 years ago)
I'd guess surge resistance and redundancy, rather than power dissipation.

Looks like 10 stages of 5x parallel 2k going left to right??  So that's 10x400 = 4k. Perhaps used for parallel damping the DC link???? (the 6 subcircuits below would be the 3phase half bridges...). Presumably then the DC link would be prone to big inductive spikes (thus HV), as various diodes return to it. 

If it were exclusively thermal / non-momentary power dissipation, I think the pads could have been made larger and/or more widely spread relative to the resistor package- not 100% sure this is always the case however.