Thermal insulators "Phase Change Material"

H

Harry D

Guest
I am trying to use some Laird Tpcm 580 Series thermal isolators between
TO-247s and an al heat sink. See attached
http://www.lairdtech.com/Products/Thermal-Management-Solutions/Thermal-Interface-Materials/Phase-Change-TIMs/#.VCSCXvldXnE
The To-247 packs are 0.198" thick and I am using a double layer of 5810
material which is 0.010" each thick with 0.217" spacers.The screws are
torqued down and at about 150Vdc the smokes escapes. Of cause I can use a
normal Sil pads with their terrible thermal resistance and all is well. I
need the 0.016C/W of the PCM to allow full power operation.
Has anybody used this material? What am I doing wrong?

Harry
 
Den torsdag den 25. september 2014 23.17.53 UTC+2 skrev Harry D:
I am trying to use some Laird Tpcm 580 Series thermal isolators between

TO-247s and an al heat sink. See attached

http://www.lairdtech.com/Products/Thermal-Management-Solutions/Thermal-Interface-Materials/Phase-Change-TIMs/#.VCSCXvldXnE

The To-247 packs are 0.198" thick and I am using a double layer of 5810

material which is 0.010" each thick with 0.217" spacers.The screws are

torqued down and at about 150Vdc the smokes escapes. Of cause I can use a

normal Sil pads with their terrible thermal resistance and all is well. I

need the 0.016C/W of the PCM to allow full power operation.

Has anybody used this material? What am I doing wrong?



Harry
Click to expand...

afaict tell from the datasheet at maximum compression is is 0.013 C-inch^2/W

a TO247 is less that half an inch^2

-Lasse
 
Den fredag den 26. september 2014 01.53.22 UTC+2 skrev Harry D:
"Lasse Langwadt Christensen" wrote in message

news:31ab8632-58f9-4dec-9e6f-38bace4f7302@googlegroups.com...



Den torsdag den 25. september 2014 23.17.53 UTC+2 skrev Harry D:

I am trying to use some Laird Tpcm 580 Series thermal isolators between



TO-247s and an al heat sink. See attached



http://www.lairdtech.com/Products/Thermal-Management-Solutions/Thermal-Interface-Materials/Phase-Change-TIMs/#.VCSCXvldXnE



The To-247 packs are 0.198" thick and I am using a double layer of 5810



material which is 0.010" each thick with 0.217" spacers.The screws are



torqued down and at about 150Vdc the smokes escapes. Of cause I can use a



normal Sil pads with their terrible thermal resistance and all is well. I



need the 0.016C/W of the PCM to allow full power operation.



Has anybody used this material? What am I doing wrong?







Harry



afaict tell from the datasheet at maximum compression is is 0.013 C-inch^2/W



a TO247 is less that half an inch^2



-Lasse

So if 0.5 the area is that not 2x the thermal resistance?
Click to expand...

yes so 0.026 you said you need 0.016

-Lasse
 
On Thu, 25 Sep 2014 14:17:53 -0700, "Harry D" <harryd@tdsystems.org>
wrote:

I am trying to use some Laird Tpcm 580 Series thermal isolators between
TO-247s and an al heat sink. See attached
http://www.lairdtech.com/Products/Thermal-Management-Solutions/Thermal-Interface-Materials/Phase-Change-TIMs/#.VCSCXvldXnE
The To-247 packs are 0.198" thick and I am using a double layer of 5810
material which is 0.010" each thick with 0.217" spacers.The screws are
torqued down and at about 150Vdc the smokes escapes. Of cause I can use a
normal Sil pads with their terrible thermal resistance and all is well. I
need the 0.016C/W of the PCM to allow full power operation.
Has anybody used this material? What am I doing wrong?

Harry
Click to expand...

These are not usually considered to be insulators. We tried phase
change stuff and hated it.

0.016 K/W will be really hard.

Hard anodize on the heat sink, with grease, is about the best you'll
do if you need insulation.

More extreme: use a heat spreader block and insulate that from the
heat sink.

Even better, don't insulate the transistors from the heat sink.


--

John Larkin Highland Technology, Inc

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com
 
On 25-09-2014 23:17, Harry D wrote:
I am trying to use some Laird Tpcm 580 Series thermal isolators between
TO-247s and an al heat sink. See attached
http://www.lairdtech.com/Products/Thermal-Management-Solutions/Thermal-Interface-Materials/Phase-Change-TIMs/#.VCSCXvldXnE

The To-247 packs are 0.198" thick and I am using a double layer of 5810
material which is 0.010" each thick with 0.217" spacers.The screws are
torqued down and at about 150Vdc the smokes escapes. Of cause I can use
a normal Sil pads with their terrible thermal resistance and all is
well. I need the 0.016C/W of the PCM to allow full power operation.
Has anybody used this material? What am I doing wrong?

Harry
Click to expand...

Perhaps a stupid thought, but are you sure they are intended for high
voltage applications?
I find it suspicious that they don't specify a breakdown voltage in the
datasheet. A high volume resistivity doesn't imply a high breakdown
voltage. The application examples are all low voltage, too.

Klaus
 
On Thu, 25 Sep 2014 23:37:47 +0200, Klaus Bahner
<Klaus.Bahner@ieee.org> wrote:

On 25-09-2014 23:17, Harry D wrote:
I am trying to use some Laird Tpcm 580 Series thermal isolators between
TO-247s and an al heat sink. See attached
http://www.lairdtech.com/Products/Thermal-Management-Solutions/Thermal-Interface-Materials/Phase-Change-TIMs/#.VCSCXvldXnE

The To-247 packs are 0.198" thick and I am using a double layer of 5810
material which is 0.010" each thick with 0.217" spacers.The screws are
torqued down and at about 150Vdc the smokes escapes. Of cause I can use
a normal Sil pads with their terrible thermal resistance and all is
well. I need the 0.016C/W of the PCM to allow full power operation.
Has anybody used this material? What am I doing wrong?

Harry



Perhaps a stupid thought, but are you sure they are intended for high
voltage applications?
I find it suspicious that they don't specify a breakdown voltage in the
datasheet. A high volume resistivity doesn't imply a high breakdown
voltage. The application examples are all low voltage, too.

Klaus
Click to expand...

I agree, it's not an insulator. Once it changes phase, the insulator
properties probably go to hell.

Cheers
 
On Thu, 25 Sep 2014 14:17:53 -0700, "Harry D" <harryd@tdsystems.org>
wrote:

I am trying to use some Laird Tpcm 580 Series thermal isolators between
TO-247s and an al heat sink. See attached
http://www.lairdtech.com/Products/Thermal-Management-Solutions/Thermal-Interface-Materials/Phase-Change-TIMs/#.VCSCXvldXnE
The To-247 packs are 0.198" thick and I am using a double layer of 5810
material which is 0.010" each thick with 0.217" spacers.The screws are
torqued down and at about 150Vdc the smokes escapes. Of cause I can use a
normal Sil pads with their terrible thermal resistance and all is well. I
need the 0.016C/W of the PCM to allow full power operation.
Has anybody used this material? What am I doing wrong?

Harry
Click to expand...

They are classified as "Thermal-Interface-Materials", not an
insulator.

Cheers
 
"Lasse Langwadt Christensen" wrote in message
news:31ab8632-58f9-4dec-9e6f-38bace4f7302@googlegroups.com...

Den torsdag den 25. september 2014 23.17.53 UTC+2 skrev Harry D:
I am trying to use some Laird Tpcm 580 Series thermal isolators between

TO-247s and an al heat sink. See attached

http://www.lairdtech.com/Products/Thermal-Management-Solutions/Thermal-Interface-Materials/Phase-Change-TIMs/#.VCSCXvldXnE

The To-247 packs are 0.198" thick and I am using a double layer of 5810

material which is 0.010" each thick with 0.217" spacers.The screws are

torqued down and at about 150Vdc the smokes escapes. Of cause I can use a

normal Sil pads with their terrible thermal resistance and all is well. I

need the 0.016C/W of the PCM to allow full power operation.

Has anybody used this material? What am I doing wrong?



Harry
Click to expand...

afaict tell from the datasheet at maximum compression is is 0.013 C-inch^2/W

a TO247 is less that half an inch^2

-Lasse
So if 0.5 the area is that not 2x the thermal resistance?

Harry
 
"John Larkin" wrote in message
news:gn192alc6tgtfibqvjgimvqav4u5hipgj2@4ax.com...

On Thu, 25 Sep 2014 14:17:53 -0700, "Harry D" <harryd@tdsystems.org>
wrote:

I am trying to use some Laird Tpcm 580 Series thermal isolators between
TO-247s and an al heat sink. See attached
http://www.lairdtech.com/Products/Thermal-Management-Solutions/Thermal-Interface-Materials/Phase-Change-TIMs/#.VCSCXvldXnE
The To-247 packs are 0.198" thick and I am using a double layer of 5810
material which is 0.010" each thick with 0.217" spacers.The screws are
torqued down and at about 150Vdc the smokes escapes. Of cause I can use a
normal Sil pads with their terrible thermal resistance and all is well. I
need the 0.016C/W of the PCM to allow full power operation.
Has anybody used this material? What am I doing wrong?

Harry
Click to expand...

These are not usually considered to be insulators. We tried phase
change stuff and hated it.

0.016 K/W will be really hard.

Hard anodize on the heat sink, with grease, is about the best you'll
do if you need insulation.

More extreme: use a heat spreader block and insulate that from the
heat sink.

Even better, don't insulate the transistors from the heat sink.


--

John Larkin Highland Technology, Inc

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

What is this magic heat spreader block?

Will hard anodize withstand 630V. ....270Vdc surge to 430/.7= 614VDC

Harry


Harry
 
On Thu, 25 Sep 2014 16:59:49 -0700, "Harry D" <harryd@tdsystems.org>
wrote:

"John Larkin" wrote in message
news:gn192alc6tgtfibqvjgimvqav4u5hipgj2@4ax.com...

On Thu, 25 Sep 2014 14:17:53 -0700, "Harry D" <harryd@tdsystems.org
wrote:

I am trying to use some Laird Tpcm 580 Series thermal isolators between
TO-247s and an al heat sink. See attached
http://www.lairdtech.com/Products/Thermal-Management-Solutions/Thermal-Interface-Materials/Phase-Change-TIMs/#.VCSCXvldXnE
The To-247 packs are 0.198" thick and I am using a double layer of 5810
material which is 0.010" each thick with 0.217" spacers.The screws are
torqued down and at about 150Vdc the smokes escapes. Of cause I can use a
normal Sil pads with their terrible thermal resistance and all is well. I
need the 0.016C/W of the PCM to allow full power operation.
Has anybody used this material? What am I doing wrong?

Harry

These are not usually considered to be insulators. We tried phase
change stuff and hated it.

0.016 K/W will be really hard.

Hard anodize on the heat sink, with grease, is about the best you'll
do if you need insulation.

More extreme: use a heat spreader block and insulate that from the
heat sink.

Even better, don't insulate the transistors from the heat sink.
Click to expand...

>What is this magic heat spreader block?

No magic, Harry Potter. Bolt the transistor to a copper block, and
insulate the block from the heat sink. Theta goes down because the
insulator area increases. You get a bonus reduction in theta by
reducing the spreading thermal resistance of the heat sink itself.

Another possibility is to make the spreader block out of aluminum,
bare on top and anodized on the bottom, for the insulation.

All machined flat and greased, of course. The main heat sink needs to
be flat, too.

Here's an aluminum heatsink with copper heat spreaders. No
insulators... the heat sink itself is mounted on delrin blocks.

https://dl.dropboxusercontent.com/u/53724080/Thermal/Amp.jpg


>Will hard anodize withstand 630V. ....270Vdc surge to 430/.7= 614VDC

You mentioned 150 VDC. I wouldn't recommend anodize above 200 volts.



--

John Larkin Highland Technology, Inc

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com
 
On Thu, 25 Sep 2014 17:13:45 -0700, John Larkin
<jlarkin@highlandtechnology.com> wrote:

On Thu, 25 Sep 2014 16:59:49 -0700, "Harry D" <harryd@tdsystems.org
wrote:



"John Larkin" wrote in message
news:gn192alc6tgtfibqvjgimvqav4u5hipgj2@4ax.com...

On Thu, 25 Sep 2014 14:17:53 -0700, "Harry D" <harryd@tdsystems.org
wrote:

I am trying to use some Laird Tpcm 580 Series thermal isolators between
TO-247s and an al heat sink. See attached
http://www.lairdtech.com/Products/Thermal-Management-Solutions/Thermal-Interface-Materials/Phase-Change-TIMs/#.VCSCXvldXnE
The To-247 packs are 0.198" thick and I am using a double layer of 5810
material which is 0.010" each thick with 0.217" spacers.The screws are
torqued down and at about 150Vdc the smokes escapes. Of cause I can use a
normal Sil pads with their terrible thermal resistance and all is well. I
need the 0.016C/W of the PCM to allow full power operation.
Has anybody used this material? What am I doing wrong?

Harry

These are not usually considered to be insulators. We tried phase
change stuff and hated it.

0.016 K/W will be really hard.

Hard anodize on the heat sink, with grease, is about the best you'll
do if you need insulation.

More extreme: use a heat spreader block and insulate that from the
heat sink.

Even better, don't insulate the transistors from the heat sink.


What is this magic heat spreader block?

No magic, Harry Potter. Bolt the transistor to a copper block, and
insulate the block from the heat sink. Theta goes down because the
insulator area increases. You get a bonus reduction in theta by
reducing the spreading thermal resistance of the heat sink itself.

Another possibility is to make the spreader block out of aluminum,
bare on top and anodized on the bottom, for the insulation.

All machined flat and greased, of course. The main heat sink needs to
be flat, too.

Here's an aluminum heatsink with copper heat spreaders. No
insulators... the heat sink itself is mounted on delrin blocks.

https://dl.dropboxusercontent.com/u/53724080/Thermal/Amp.jpg


Will hard anodize withstand 630V. ....270Vdc surge to 430/.7= 614VDC

You mentioned 150 VDC. I wouldn't recommend anodize above 200 volts.
Click to expand...

Oh, a good high-voltage insulator is greased aluminum nitride. Might
need a heat spreader.


--

John Larkin Highland Technology, Inc

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com
 
On Thu, 25 Sep 2014 14:17:53 -0700, "Harry D" <harryd@tdsystems.org>
wrote:

I am trying to use some Laird Tpcm 580 Series thermal isolators between
TO-247s and an al heat sink. See attached
http://www.lairdtech.com/Products/Thermal-Management-Solutions/Thermal-Interface-Materials/Phase-Change-TIMs/#.VCSCXvldXnE
The To-247 packs are 0.198" thick and I am using a double layer of 5810
material which is 0.010" each thick with 0.217" spacers.The screws are
torqued down and at about 150Vdc the smokes escapes. Of cause I can use a
normal Sil pads with their terrible thermal resistance and all is well. I
need the 0.016C/W of the PCM to allow full power operation.
Has anybody used this material? What am I doing wrong?
Click to expand...

That stuff has a huge thermal resistance. I got a sample and tried
it. Except for gap filling, it is useless.

I use the Laird K52-1 kapton product in our Roy induction heaters.

http://lairdtech.thomasnet.com/item/all-categories/tgard-8482-k52-series-insulator-material/pn-4037

It withstands the 1500 volt HiPot test each unit must pass. 0.13
thermal resistance with at least 50 lbs clamping force.

I think you slipped a decimal in your thermal resistance requirement.
The thermal resistance of the die to package of the IRG7PH46U-EP IGBT
in the TO-247 package is 0.32.

John
John DeArmond
http://www.neon-john.com
http://www.fluxeon.com
Tellico Plains, Occupied TN
See website for email address
 
On Fri, 26 Sep 2014 03:33:44 -0400, Neon John <no@never.com> wrote:

On Thu, 25 Sep 2014 14:17:53 -0700, "Harry D" <harryd@tdsystems.org
wrote:

I am trying to use some Laird Tpcm 580 Series thermal isolators between
TO-247s and an al heat sink. See attached
http://www.lairdtech.com/Products/Thermal-Management-Solutions/Thermal-Interface-Materials/Phase-Change-TIMs/#.VCSCXvldXnE
The To-247 packs are 0.198" thick and I am using a double layer of 5810
material which is 0.010" each thick with 0.217" spacers.The screws are
torqued down and at about 150Vdc the smokes escapes. Of cause I can use a
normal Sil pads with their terrible thermal resistance and all is well. I
need the 0.016C/W of the PCM to allow full power operation.
Has anybody used this material? What am I doing wrong?


That stuff has a huge thermal resistance. I got a sample and tried
it. Except for gap filling, it is useless.
Click to expand...

Dow 340 grease will squeeze down to under 100 micro-inches (my
measurement resolution) with moderate pressure. The phase-change gorp
oozes out a bit around the edges but stays mills thick, so has a lot
more theta than grease. Neither insulates.

If you replace a transistor, the gorp is messier than the grease.


I use the Laird K52-1 kapton product in our Roy induction heaters.

http://lairdtech.thomasnet.com/item/all-categories/tgard-8482-k52-series-insulator-material/pn-4037

It withstands the 1500 volt HiPot test each unit must pass. 0.13
thermal resistance with at least 50 lbs clamping force.
Click to expand...

Kapton is a great insulator, but theta is huge.

I think you slipped a decimal in your thermal resistance requirement.
The thermal resistance of the die to package of the IRG7PH46U-EP IGBT
in the TO-247 package is 0.32.

John
John DeArmond
http://www.neon-john.com
http://www.fluxeon.com
Tellico Plains, Occupied TN
See website for email address
Click to expand...

--

John Larkin Highland Technology, Inc

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com
 
"Neon John" wrote in message
news:a65a2ap98iie1paolkrqstpgv1qj7sfrrt@4ax.com...

On Thu, 25 Sep 2014 14:17:53 -0700, "Harry D" <harryd@tdsystems.org>
wrote:

I am trying to use some Laird Tpcm 580 Series thermal isolators between
TO-247s and an al heat sink. See attached
http://www.lairdtech.com/Products/Thermal-Management-Solutions/Thermal-Interface-Materials/Phase-Change-TIMs/#.VCSCXvldXnE
The To-247 packs are 0.198" thick and I am using a double layer of 5810
material which is 0.010" each thick with 0.217" spacers.The screws are
torqued down and at about 150Vdc the smokes escapes. Of cause I can use a
normal Sil pads with their terrible thermal resistance and all is well. I
need the 0.016C/W of the PCM to allow full power operation.
Has anybody used this material? What am I doing wrong?
Click to expand...

That stuff has a huge thermal resistance. I got a sample and tried
it. Except for gap filling, it is useless.

I use the Laird K52-1 kapton product in our Roy induction heaters.

http://lairdtech.thomasnet.com/item/all-categories/tgard-8482-k52-series-insulator-material/pn-4037

It withstands the 1500 volt HiPot test each unit must pass. 0.13
thermal resistance with at least 50 lbs clamping force.

I think you slipped a decimal in your thermal resistance requirement.
The thermal resistance of the die to package of the IRG7PH46U-EP IGBT
in the TO-247 package is 0.32.

John
John DeArmond
http://www.neon-john.com
http://www.fluxeon.com
Tellico Plains, Occupied TN
See website for email address

Hey John,
Thanks for your input and I went with your K-52 material.
No I did not slip a digit, my die to package is 0.25 C/W and added to the
K-52 is about 1.0 c/w die to HS. I am using 4 Si-C MOSFETS C2M0025120D that
will dissipate about 60W per To-247, pushing them like JL. Try some of those
SiCs, in bridge circuits, it sure saves power. The gates are driven from
+15V to -7.0V for safe operation.

Cheers, Harry


Cheers, Harry
 
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