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9651Re: [solectria_ev] RE: Looking for an AMC325 to help troubleshoot.

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  • Wolf
    Feb 3 7:57 AM
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      I re-sold it to Doug, (same price I paid  to Dan).

      I have Dan's old controller, which is still under repair... I could get it back up and running for around $1000.00

      It had the following failure mode:

      1. Failed voltage reference, which caused the main power supply to operate with the current loop only (no voltage regulation).

      2. This glitches the speed decoder which caused improper MOSFET drive signals.

      3. Excessive drive current melted the motor connector, causing the contacts to separate.

      4. Arching at the motor connector caused extremely high voltage across the power diodes.

      5. Once a diode failed open, the remaining diodes had to take up the failed ones load, which caused them to all quickly fail.

      6. With out the diodes, the MOSFETs went into avalanche conduction.

      7. This causes the observed shuttering/bucking during regen.

      8. Shuttering/bucking during regen, causes excessive current draw, go back to step 3. ;)

      The power supply board has been repaired.

      Next is to replace the 48 power diodes, (with equivalents, since they are obsolete).

      There is a possibility that the 48 power MOSFETs might need to be replaced too, they are fully avalanche rated, but I am not sure how high a voltage they got exposed to, and there would be asymmetric current sharing between them, so some could be weakened with damaged cells.

      I can still get the original 3rd gen 250V MOSFETs... But if I am going to replace them all I might as well jump to an equivalent 300V 6th gen MOSFET.

      And then replace all the 250V bulk caps with 300V.

      Then the controller would meet the typical 50% working voltage margin, rather than the 20% it is now.

      On Feb 3, 2014 2:56 AM, "Daniel Hockaday" <daniel_hockaday@...> wrote:

      Sorry, it's been sold to Wolf.

      From: "ehsif727@..." <ehsif727@...>
      To: solectria_ev@yahoogroups.com
      Sent: Sunday, February 2, 2014 1:54 PM
      Subject: [solectria_ev] RE: Looking for an AMC325 to help troubleshoot.
      Are you still selling the controller to you damaged Force

      ---In solectria_ev@yahoogroups.com, <daniel_hockaday@...> wrote:
      Hi Wolf, Dan Hockaday here, I have one for sale. 
      My wife's 97 Solectria Force was rear-ended at about 45mphs. 
      The car was totaled due to a bent frame.  Back doors and trunk no longer work.  All electrical parts are in working order.  I drove the car onto a trailer to get it home.  We are still using the gel cell batteries which I have moved over to our Grumman.  Not sure what to ask for regarding price.  Our car had a total of 17,000 miles on it at the time of the wreck, on 
      Aug 27, 2013.  I tried looking on ebay but no luck.  Shoot me an offer if your interested.

      From: Wolf <wolf@...>
      To: "solectria_ev@yahoogroups.com" <solectria_ev@yahoogroups.com>
      Sent: Tuesday, January 7, 2014 10:56 AM
      Subject: [solectria_ev] Looking for an AMC325 to help troubleshoot.

      I am looking for a working or non-working AMC325 to buy.
      I could also borrow one... but I am worried it might get damaged. 

      I have been working on an AMC325 for a while now, and have gotten stuck.

      This particular controller has a power supply problem, which it looks like, propagated thru and damaged other parts.

      I don't have enough functional AMC325 parts to do "swaptronics" to locate which parts are bad (this controller acts like it has more than one problem).

      Known issues:
      1. The main power supply voltage sense had failed, and was outputting very high voltage and relying on the over current circuit to regulate power. (The main power supply board has been fixed and seems to be working fine now.)

      2. Noise from the power supply was messing up the rotor speed circuit, such that it was causing the motor to be driven incorrectly.

      3. The motor driven incorrectly resulted in extremely high currents which melted the motor connector.

      4. When the motor connector failed, high voltage arching resulted in damage to the power stage MOSFETs and/or Diodes.

      This is where I am stuck, I don't have enough working gate drivers and power stages (3-phase half bridges), to swap and test with.

      The controller with no load can spin the motor (under load, power is asymmetric), and when commanded to regen, causes the motor to speed up and oscillate in velocity.

      Essentially I need parts to get this controller working, and then once working, I know which parts are bad and can start on a component level repair.

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