Crushed Transformer

DreadPirate · 10th July 2009, 05:34 PM

Damaged transformer in transit, has an indentation where it hit a nearby circuit board, now has an 1/8" deep gap at that location, wires under it crushed. I know this is unsafe to operate. My guess is that the insulation has cracked and could fail. Also, if the wires have narrowed, could create a hot spot. What's the worse that could happen? This is a 1000VA beast.

infinia · 10th July 2009, 06:12 PM

Quote:

Also, if the wires have narrowed, could create a hot spot. What's the worse that could happen? This is a 1000VA beast.

Oh I don't know.. you could burn an attorney's house down.

DreadPirate · 10th July 2009, 06:16 PM

Quote:

Originally posted by infinia

Oh I don't know.. you could burn an attorney's house down.

As long as it also takes the cats, I think I can live with that.

Groundloops · 10th July 2009, 06:31 PM

A detail photo would be helpful to consider the damage. What I would try (not claiming to have the best idea) is to attach a mains connector, plug it into the socket and pull it out again immediately. If the primary winding is shorted, the mains fuse will trigger. If a secondary winding is shorted, you will hear the transformer "gnarl" with mains frequency. The sound will be quite distinct.

If no gnarling occurs, measure the secondary´s voltage(s). If they are o.k., connect a (dummy) load to it and observe.

Worst case is that the winding(s) heat up, the insulation goes up in smoke and later the windings will start to melt. But that would take some time, much more than you´ll need to hear it gnarl and pull the plug.

No need to say that you should not have the transformer lying on your bosom while trying that. Keep away from it some feet.

DreadPirate · 10th July 2009, 10:58 PM

You asked for it, you got it. The first picture is the transformer, an 1100VA monster. It slammed against the circuit board which ended up crushing it to a depth of about 1/8". The xformer is made by JMP Electronics which supplied Aragon and on Monday I will find out if these might still be available. The next picture shows the rectifiers mounted on the board that got impacted. The pins are bent in the direction of the impact location. The last picture is the rectifiers from above. The leftmost one is the most displaced, it is closest to the impact location. A shame, but amazing how well built this thing is, it probably survived a freefall drop of about 5'. Thank you UPS.

DreadPirate · 10th July 2009, 11:16 PM

Closeup of the transformer.

DreadPirate · 10th July 2009, 11:20 PM

Closeup of rectifiers.

infinia · 10th July 2009, 11:28 PM

My guess it's repairable. Remove transformer and carefully peel back insulation at the affected area. Inspect with a magnifying glass and remove any debris. Use 2 part epoxy to reinsulated damaged enamal coating. Test with a variac with no load first. UPS won't cover the damage?

DreadPirate · 11th July 2009, 01:46 AM

My first inclination is to just leave alone. It appears to be working fine, at least sound-wise, I've taken no measurements. The seller knows I have the right to send this baby back, but is not pressing the issue. UPS has probably already notified him they will not pay the claim for one reason or another, though they clearly dropped the unit, the impact damage is readily apparent. I've got a line on "Mike the Technician" at JMP Electronics who allegedly worked on supplying these transformers for Aragon back in the day. If I can get an exact replacement (who knows, maybe they were matched or something and its not possible) I may hit the seller up for it and a bit of additional restitution. What's amazing is how well built this thing is, it took some cosmetic damage on the faceplate, but given the fact that it was dropped in freefall for about 5' and still works is quite a feat.

infinia · 11th July 2009, 01:52 AM

It looks worse than it is. Luckily it hit where the flying leads are attached more cushin'.

10th July 2009, 05:34 PM	#1
DreadPirate diyAudio Member Join Date: Jan 2006 Location: Northern Virginia, USA	Crushed Transformer Damaged transformer in transit, has an indentation where it hit a nearby circuit board, now has an 1/8" deep gap at that location, wires under it crushed. I know this is unsafe to operate. My guess is that the insulation has cracked and could fail. Also, if the wires have narrowed, could create a hot spot. What's the worse that could happen? This is a 1000VA beast.

10th July 2009, 11:28 PM	#8
infinia diyAudio Member Join Date: May 2005 Location: Californication	Cuts like a knife My guess it's repairable. Remove transformer and carefully peel back insulation at the affected area. Inspect with a magnifying glass and remove any debris. Use 2 part epoxy to reinsulated damaged enamal coating. Test with a variac with no load first. UPS won't cover the damage? __________________ like four million tons of hydrogen exploding on the sun like the whisper of the termites building castles in the dust

11th July 2009, 01:52 AM	#10
infinia diyAudio Member Join Date: May 2005 Location: Californication	It looks worse than it is. Luckily it hit where the flying leads are attached more cushin'. __________________ like four million tons of hydrogen exploding on the sun like the whisper of the termites building castles in the dust

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10th July 2009, 06:31 PM	#4
Groundloops I´m amazed! diyAudio Member Join Date: May 2004 Location: Hamburg / Northern Germany	A detail photo would be helpful to consider the damage. What I would try (not claiming to have the best idea) is to attach a mains connector, plug it into the socket and pull it out again immediately. If the primary winding is shorted, the mains fuse will trigger. If a secondary winding is shorted, you will hear the transformer "gnarl" with mains frequency. The sound will be quite distinct. If no gnarling occurs, measure the secondary´s voltage(s). If they are o.k., connect a (dummy) load to it and observe. Worst case is that the winding(s) heat up, the insulation goes up in smoke and later the windings will start to melt. But that would take some time, much more than you´ll need to hear it gnarl and pull the plug. No need to say that you should not have the transformer lying on your bosom while trying that. Keep away from it some feet.

11th July 2009, 01:46 AM	#9
DreadPirate diyAudio Member Join Date: Jan 2006 Location: Northern Virginia, USA	My first inclination is to just leave alone. It appears to be working fine, at least sound-wise, I've taken no measurements. The seller knows I have the right to send this baby back, but is not pressing the issue. UPS has probably already notified him they will not pay the claim for one reason or another, though they clearly dropped the unit, the impact damage is readily apparent. I've got a line on "Mike the Technician" at JMP Electronics who allegedly worked on supplying these transformers for Aragon back in the day. If I can get an exact replacement (who knows, maybe they were matched or something and its not possible) I may hit the seller up for it and a bit of additional restitution. What's amazing is how well built this thing is, it took some cosmetic damage on the faceplate, but given the fact that it was dropped in freefall for about 5' and still works is quite a feat.

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