Fwd: Trace 4024 and MREF [RE-wrenches]

Tue May 16 18:04:07 PDT 2000

<x-flowed>Tom & Richard,
Just had a similar problem with a three year old 4024. Mine was not 
as catastrophic. Basically, Trace was using inferior fans for awhile. 
These fans would crap out after a time at 30VDC or so (like, an 
equalizing charge?)  and the inverter would get seriously hot when 
being used as a charger. In my customer's case, it didn't take out 
the FETs, but cooked the firmware to the point where it was corrupted 
and doing a Low Batt shutdown even though the battery voltage was 
fine. Probably the thing that saved the FETs. Trace charged for the 
fix (although they were reasonable about it) because the machine was 
out of warranty.
I too, had to pull a new machine out of stock to keep these older 
folks on line until Trace could turn it around. Now, like you, I have 
a used new inverter to try to sell.
The only good parts here are that we can sleep well at night knowing 
we did the right thing by our customers and you have a war story to 
tell the next guy that whines because you won't meet the price of one 
of the bloodsucking deep discounters.
Best, bob-O

>Hello Wrenches
>
>Anyone got any feedback on this Trace SW4024 problem listed below?
>
>Richard
>
>>From: "Tom Elliot" <telliot at wagonmaker.com>
>>To: "Richard Perez" <richard.perez at homepower.org>
>>Subject: Trace 4024 and MREF
>>Date: Tue, 16 May 2000 15:09:00 -0600
>>X-Priority: 3
>>
>>Richard,
>>
>>I just had an interesting experience with my original Trace 4024 that I
>>thought I'd run by you.
>>
>>The unit failed one day with a heatsink overtemp condition in the battery
>>charger fairly early in the charging cycle (apparently the earlier units
>>were not as well protected from overtemping as the current units) that
>>corrected itself within 15 minutes.  The unit seemed to be producing power
>>OK afterward but since it had failed during a charge cycle and gotten hot as
>>hell in the process I sent it back in for a rebuild and upgrade.  I was
>>fortunate to have another unit in stock I could use in its place.
>>
>>When the tech called me to give me the price he told me an interesting story
>>about the failure.  It seems all 4 high end FETs had failed (he said the
>>board was "obviously burned") and that had apparently contributed to the
>>failure in the charger (though I'm not sure what the connection is there).
>>When I asked him how that could happen he said that high voltage on the
>>charger side could cause it and that generators could easily put out such
>>high charges.
>>
>>It seemed strange to me that if it were such a common occurrence they
>>wouldn't have protected the system from it but apparently the FETs are good
>>to 200 volts.  It turns out that when a generator runs out of gas (which is
>>bound to happen sooner or later with all gas generators) the generator
>>spikes the voltage to try to compensate.  When that happens unregulated
>>voltages of 200 + are easily possible.
>>
>>This was apparently when the FETs started to go but according to the tech it
>>isn't a catastrophic failure but a cumulative one and there is no indication
>>from the unit that such a failure is occurring.  When I asked him what that
>>does to the unit he said it basically causes the unit to cease being a sine
>>wave and revert to modified square wave (I just can't bring myself to call
>>it modified sinewave <G>).  It also reduces the surge capacity but if no
>>large loads were being run the reduced capacity would never be noticed.
>>
>>It strikes me as odd that the unit could undergo such a failure without any
>>indication that it has happened and wonder if there aren't a lot of
>>"sinewave" 4024s out there that are now acting as mod square wave units.
>>The only way we noticed it was when the battery charger failed.
>>
>>I was wondering if you could do some checking on that and if you might want
>>to warn some folks of the dangers of letting generators run out of gas.  I
>>have never seen any indication in any of the literature that it was
>>something to watch out for and with such devastating results you'd think
>>someone would make mention of it.
>>
>>
>>Tom Elliot
>>Guffey Energy Works
>>Solar Energy Education
>>http://www.wagonmaker.com
>
>------------------------------------
>Richard Perez
>Home Power
>PO Box 520, Ashland, OR 97520  USA
>Tele: 530-475-3179
>FAX: 530-475-0836
>Subscriptions: 800-707-6585
>mailto:richard.perez at homepower.com
>Web: http://www.homepower.com
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Bob-O Schultze, Electron Connection
PO Box 203, Hornbrook, CA 96044
800.945.7587 fax 530-475-3401
www.electronconnection.com
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