Author Topic: Customer let the smoke out  (Read 115 times)

EW Zuber

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Customer let the smoke out
« on: January 12, 2019, 05:08:51 AM »
Customer calls today. His Outback VFX3648 was malfunctioning with a stuck internal transfer relay.  For some reason he turned the B+ breaker to his Midnite Classic off and immediately turned it back on.  I suspect this caused reverse current in the power MOSFET's because the unit smoked. (it was after sunset and totally dark out)
Wondering what engineering thinks about this?
I am scheduled to go to his place tomorrow so I haven't seen the unit yet.
TNX
(6) Solar World 175 watt, (14) Arco Solar 33 Watt, (15) REC 250 watt, 2KW Whirlwind turbine on 85' rohn 25 tower, Outback VFX 3648, Outback FM80 and Midnite Classic 150 w/WBJR, ( 8 ) Trojan L-16REB, 
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boB

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Re: Customer let the smoke out
« Reply #1 on: January 12, 2019, 06:47:47 PM »
Interesting but not sure why the smoke would escape from the Classic ?

The VFX3648 has a stuck ON transfer relay huh ?   Hmmmm....   That will cause some interesting issues but doesn't make a lot of sense from the Classic point of view unless maybe the battery voltage got REALLY high for whatever reason ?

With low PV input voltage compared with the battery voltage (it was after sunset), the Classic should not even try to turn on....  The  Classics' MOSFETS are on the internal side of its relay which should disconnect the battery from the FETs.  The battery is usually what causes the smoke to come out.

Unless maybe the Classic's relay was also stuck on ?  That would be some kind of double fault too so double whammy.

Interested to hear what the deal is.  Will post again if I think of something else.

boB
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mike90045

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Re: Customer let the smoke out
« Reply #2 on: January 12, 2019, 08:15:56 PM »
You can get some + Gnd replacement smoke, but I'm not sure about the best way to install it.
http://tinyurl.com/LMR-Solar

Classic 200| 2Kw PV, 160Voc | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph )| Listeroid 6/1, st5 gen head | XW6048 inverter/chgr | midnight ePanel & 4 SPDs | 48V, 800A NiFe battery bank | MS-TS-MPPT60 w/3Kw PV

EW Zuber

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Re: Customer let the smoke out
« Reply #3 on: January 13, 2019, 12:30:38 AM »
Picked up the Classic today, pulled the cover and the bar that holds the FET's to their heat sink, and it appears that most or all of the power FET's fried.
Thinking that maybe the Outback put some 120VAC onto the battery. But I can't find a block diagram for it so only guessing at this point.
Customer said lights on the OB blinked and it sounds like it tried repeatedly to unstick the relay.
If the output FET's double as AC out and battery charger regulators then I'm thinking it may be possible for 120VAC to inadvertently get momentarily applied to the batteries.
Or possibly the generator momentarily put 120 VAC on the batteries through the OB relay.
« Last Edit: January 13, 2019, 12:34:27 AM by EW Zuber »
(6) Solar World 175 watt, (14) Arco Solar 33 Watt, (15) REC 250 watt, 2KW Whirlwind turbine on 85' rohn 25 tower, Outback VFX 3648, Outback FM80 and Midnite Classic 150 w/WBJR, ( 8 ) Trojan L-16REB, 
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boB

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Re: Customer let the smoke out
« Reply #4 on: January 13, 2019, 02:47:05 AM »

One way to try un-sticking a relay is to give the inverter a good smack to jar it loose.

May not always work and not always a permanent fix if the contacts are really burnt.

K7IQ

ClassicCrazy

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Re: Customer let the smoke out
« Reply #5 on: January 13, 2019, 01:53:18 PM »
I saw where an elevator technician broke the top of the relay plastic open a bit  to put some contact cleaner in there or something to get the elevator running again until they could order a new relay to replace it - and it was a smaller relay on a control board.  Guess you do what you gotta do in a pinch when there are hundreds of people who don't want to climb up 11 flights of stairs for a few days.

Larry 
system one
Classic 150 , 5s4p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system two
Classic 150 ,5s 135 watt Kyocero , 16s Calb 100AH LiFePO4 , Outback VFX 3648 inverter
system three
Midnite KID MPPT 24 DC in to  12 volt AGM batterie

EW Zuber

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Re: Customer let the smoke out
« Reply #6 on: January 13, 2019, 05:39:09 PM »
When I had an electronics repair shop I would use jewlers rouge on a Q-tip to polish relay contacts. It worked better than anything else I had ever used. Made them smooth and shiny. But I only used it on relay contacts that were not badly pitted or on relays that were no longer available.
I pulled the power board from the Outback and pulled the cover off the relay and the contacts are quite bad. This seems to be a problem with these inverters. This one is about 7 years old.
I think I will remove the one from my own 3648 and replace it before it sticks.   
(6) Solar World 175 watt, (14) Arco Solar 33 Watt, (15) REC 250 watt, 2KW Whirlwind turbine on 85' rohn 25 tower, Outback VFX 3648, Outback FM80 and Midnite Classic 150 w/WBJR, ( 8 ) Trojan L-16REB, 
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mike90045

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Re: Customer let the smoke out
« Reply #7 on: January 13, 2019, 06:14:44 PM »
I used to use the striker strip from a book of matches, to clean up relay contacts.   But once the thin plating goes away, the contacts are pretty much shot
« Last Edit: January 13, 2019, 06:17:07 PM by mike90045 »
http://tinyurl.com/LMR-Solar

Classic 200| 2Kw PV, 160Voc | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph )| Listeroid 6/1, st5 gen head | XW6048 inverter/chgr | midnight ePanel & 4 SPDs | 48V, 800A NiFe battery bank | MS-TS-MPPT60 w/3Kw PV