Cracked P-core

[CUtiger]

So finally got around to unwrapping some long ago purchased misc. parts from PE to store them and noticed one of the caps on a P-core coil was cracked, this was the second time this has happened for me with these particular coils.

I measured it and cracked version came out 3.379mH vs 3.364mH for the other. So really doesn't appear to be an issue but it does bother me just knowing if I use this in a finished build there will always be "damaged" part in there. Doubt it is worth the cost to ship it back for a replacement and it seems to work fine, not sure if this would affect saturation at all but I doubt it.

Probably being overly obsessive about it but could someone confirm that the cracked end shouldn't effect performance. Found a few previous threads but never really saw any conclusion to them from those who had a similar issue.

[CUtiger]

Re: Cracked P-core

Adding picture of the damage...

[Mark65]

Re: Cracked P-core

Glue it to the board with the cracked end down.;)


Mark

[r-carpenter]

Re: Cracked P-core

Couple of years ago I went back and forth with PE. They were very good with the exchange and shipping at their cost except twice P-Core inductors came cracked. That's not one but TWO exchanges. I gave up, they gave up, gave me some discount and I don't order P-Core any more. The core is powdered pressed metal something that's very brittle. Glue it back up with epoxy and forget about it.
If you decide to ship it back, PE will cover the cost, or at list they use to.

[CUtiger]

Re: Cracked P-core

Didn't cover the cost for my last returns though I didn't ever ask them to. I've always had first rate service from PE it's just that I'm not even sure the drive to go ship it back is even worth it.

I suppose gluing it to the board cracked side down will have to do:D, lesson learned though I'm not using this product anymore.

[Chris Roemer]

Re: Cracked P-core

Didn't cover the cost for my last returns though I didn't ever ask them to. I've always had first rate service from PE it's just that I'm not even sure the drive to go ship it back is even worth it.

I suppose gluing it to the board cracked side down will have to do:D, lesson learned though I'm not using this product anymore.

JMO, but it SEEMS like the "base" is just made out of the "P" material out of convenience, not necessity. Maybe the base only cracks because it's so thin (and it gets "abused" in handling?). If the (larger, more robust) core is intact, I'm guessin' that everything's OK.

[AJ]

Re: Cracked P-core

This is all down to PE's packaging. Apparently they think it's cheaper to do the odd return/exchange, than pack them right the first time. That goes for everything, not just the P-cores. I'm not trashing PE, just saying they must have some kind of trade off between return/exchange percentages and packaging costs. They have to draw the line somewhere.

Only troubles I've had with PE were bent driver frames, and the like. They've always just replaced them; I've never had to ship one back. I'm betting they'd do the same for the coils, just ask. Don't always assume they're going to want the damaged stuff back.

[billfitzmaurice]

Re: Cracked P-core

Glue it to the board with the cracked end down.;)

+1.
I find it odd that they aren't drilled for a mounting screw; they're far too heavy to trust glue. I drill a hole though them for a screw. The material is sintered, so it drills easily. :p
And cracks easily too if not properly packed.

[ridikas]

Re: Cracked P-core

^^^^ An absolutely terrible idea and advice. Please do not drill it, unless you want to severely change the inductor's inductance.

[kmibb]

Re: Cracked P-core

^^^^ An absolutely terrible idea and advice. Please do not drill it, unless you want to severely change the inductor's inductance.

Please provide some evidence that you've seen this. If Bill's done it for a while and continues to, I'm prone to believe him.

[ridikas]

Re: Cracked P-core

In this case evidence is not needed. Common knowledge on how inductors work is sufficient enough. The ferrous material inside of the inductor's core increase the inductance. If you drill a part of it out, you will severely decrease inductance.

What else did you think the core was filled with metal for?

[CUtiger]

Re: Cracked P-core

That is until you put a metal rod back through it which was the purpose of drilling the hole in the first place. When used before I just used silicone and it held it to the board no problem so I'm not going to bother with the drilling.

Besides who cares what it does to the value, I would be measuring and tweaking after wards, my only concern was really potential saturation do to the odd geometry of the fractured area.

And FYI ridikas that is one thing revel's new speakers can't achieve , the custom attention to each crossover and speaker due to variance in the parts and spend countless hours voicing each one.

Also I don't think this has anything to do with PE and absolve them of blame, they specifically put two extra layers of bubble wrap around these things and that is why I didn't unwrap them earlier.

[ridikas]

Re: Cracked P-core

CUtiger - You are wrong about the Revels. Just read some of this: http://www.harman-kardon.cz/revel/revel-performa.pdf

And that is just for their mid priced line of speakers.

http://www.stereophile.com/interviews/608kev/index.html

http://www.hometheaterhifi.com/volume_11_2/feature-interview-kevin-voecks-4-2004.html

Kevin Voecks is a very upstanding individual.

[billfitzmaurice]

Re: Cracked P-core

That is until you put a metal rod back through it which was the purpose of drilling the hole in the first place.

+1, that should be so self-evident as to require no explanation.

When used before I just used silicone and it held it to the board no problem so I'm not going to bother with the drilling.

In home use, probably OK. Most of my cabs go on the road, and with that stress even lightweight small gauge air-cores are easily dislodged when only glued in place, let alone those heavy PCores.

[ridikas]

Re: Cracked P-core

By drilling out a hole and filling it with a steel bolt (different type of metal), you will increase the inductor's distortion.