Looking to build a transient generator

A product I am designing requires a series of lab tests to judge
robustness against electrical transients.

One such test is to charge up a 100mH inductor in series with a 4 ohm
load (4ohm load to ground). Then, once the inductor is fully charged,
open the supply current to it from the high side. The resulting field
collapse will produce a substantial negative going voltage spike.

The circuit goes V+ to switch to inductor to resistor to ground.

The DUT is placed in parallel with the inductor/resistor series
combination, at the open end of the circuit once the switch is opened.

My question: I want to prolong the duration of the pulse by a factor
of 10x to create a more destructive burst of energy.

E=.5*L*I^2

I want to keep DC current through the branch the same. With that
said, one would reason I would need to bump up my inductance by a
factor of 10. This would require a 1H inductor!

Is it practical to find such a large inductance? Any ideas?

Thank you

Gerb

 

On Sep 30, 10:07 pm, "Phil Allison" <philalli...@tpg.com.au> wrote:

Gerbermultit...@gmail.com





A product I am designing requires a series of lab tests to judge
robustness against electrical transients.

One such test is to charge up a 100mH inductor in series with a 4 ohm
load (4ohm load to ground).  Then, once the inductor is fully charged,
open the supply current to it from the high side.  The resulting field
collapse will produce a substantial negative going voltage spike.

The circuit goes V+ to switch to inductor to resistor to ground.

The DUT is placed in parallel with the inductor/resistor series
combination, at the open end of the circuit once the switch is opened.

My question:  I want to prolong the duration of the pulse by a factor
of 10x to create a more destructive burst of energy.

E=.5*L*I^2

I want to keep DC current through the branch the same.  With that
said, one would reason I would need to bump up my inductance by a
factor of 10.  This would require a 1H inductor!

Is it practical to find such a large inductance?  Any ideas?

** All depends on what DC current you are testing at.

   Why not tell us ?

.....    Phil- Hide quoted text -

- Show quoted text -

You know Phil, no matter how hard I try, I always end up leaving out
some vital detail. Thanks for helping me out .

I would like to pass 3.2A +/- 200mA through the inductor. I realize
that as the inductor gains in size, so will its series DC resistance.
Therefore, at one point I might need to adjust my series resistance to
keep the branch current where I want it. This will result in a very
large inductor. Digikey does not carry these .

Gerb

 

[Phil Allison]

<Gerbermultit00l@gmail.com
"Phil Allison"

A product I am designing requires a series of lab tests to judge
robustness against electrical transients.

One such test is to charge up a 100mH inductor in series with a 4 ohm
load (4ohm load to ground). Then, once the inductor is fully charged,
open the supply current to it from the high side. The resulting field
collapse will produce a substantial negative going voltage spike.

The circuit goes V+ to switch to inductor to resistor to ground.

The DUT is placed in parallel with the inductor/resistor series
combination, at the open end of the circuit once the switch is opened.

My question: I want to prolong the duration of the pulse by a factor
of 10x to create a more destructive burst of energy.

E=.5*L*I^2

I want to keep DC current through the branch the same. With that
said, one would reason I would need to bump up my inductance by a
factor of 10. This would require a 1H inductor!

Is it practical to find such a large inductance? Any ideas?

** All depends on what DC current you are testing at.

Why not tell us ?

You know Phil, no matter how hard I try, I always end up leaving out
some vital detail. Thanks for helping me out .

I would like to pass 3.2A +/- 200mA through the inductor. I realize
that as the inductor gains in size, so will its series DC resistance.
Therefore, at one point I might need to adjust my series resistance to
keep the branch current where I want it. This will result in a very
large inductor. Digikey does not carry these .


** Hmmmm -

a 3.5 amp rated inductor of say 1 Henry would weigh more than I care to
lift.



...... Phil

 

[Tim Wescott]

Phil Allison wrote:

Gerbermultit00l@gmail.com
"Phil Allison"
A product I am designing requires a series of lab tests to judge
robustness against electrical transients.
One such test is to charge up a 100mH inductor in series with a 4 ohm
load (4ohm load to ground). Then, once the inductor is fully charged,
open the supply current to it from the high side. The resulting field
collapse will produce a substantial negative going voltage spike.
The circuit goes V+ to switch to inductor to resistor to ground.
The DUT is placed in parallel with the inductor/resistor series
combination, at the open end of the circuit once the switch is opened.
My question: I want to prolong the duration of the pulse by a factor
of 10x to create a more destructive burst of energy.
E=.5*L*I^2
I want to keep DC current through the branch the same. With that
said, one would reason I would need to bump up my inductance by a
factor of 10. This would require a 1H inductor!
Is it practical to find such a large inductance? Any ideas?
** All depends on what DC current you are testing at.

Why not tell us ?


You know Phil, no matter how hard I try, I always end up leaving out
some vital detail. Thanks for helping me out .

I would like to pass 3.2A +/- 200mA through the inductor. I realize
that as the inductor gains in size, so will its series DC resistance.
Therefore, at one point I might need to adjust my series resistance to
keep the branch current where I want it. This will result in a very
large inductor. Digikey does not carry these .


** Hmmmm -

a 3.5 amp rated inductor of say 1 Henry would weigh more than I care to
lift.

Yet how impressive it would look in the lab, with the jack points and all.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html

 

[Tim Wescott]

Gerbermultit00l@gmail.com wrote:

A product I am designing requires a series of lab tests to judge
robustness against electrical transients.

One such test is to charge up a 100mH inductor in series with a 4 ohm
load (4ohm load to ground). Then, once the inductor is fully charged,
open the supply current to it from the high side. The resulting field
collapse will produce a substantial negative going voltage spike.

The circuit goes V+ to switch to inductor to resistor to ground.

The DUT is placed in parallel with the inductor/resistor series
combination, at the open end of the circuit once the switch is opened.

My question: I want to prolong the duration of the pulse by a factor
of 10x to create a more destructive burst of energy.

E=.5*L*I^2

I want to keep DC current through the branch the same. With that
said, one would reason I would need to bump up my inductance by a
factor of 10. This would require a 1H inductor!

Is it practical to find such a large inductance? Any ideas?

That depends on your view of "practical".

You're definitely into the heavy metal category here, but that doesn't
mean you can't find something for enough $$$.

I'd check out power transformer companies -- Hammond and Peter W. Dahl
come to mind. You may be able to get something made custom, or find a
power transformer with a primary winding of around 1H.

You may also be able to start with a big-iron power transformer and
rewind it for your 1H.

Were I going to do this, and if no one here coughs up something more
concrete, _and_ if neither Hammond nor Dahl would make one, I'd do the
following: Start with Hammond's power choke catalog to get an idea of
the joules/pound of a power choke, then go shopping for surplus
equipment with a transformer that big. Then figure out the
henrys/turn^2 constant of the thing, and wind a core.

Note that if you go this route, you want to stay aware of gapped vs.
non-gapped cores -- an iron-core inductor will tend to lose inductance
as the current goes up, so the energy stored won't equal I^2/2 *
(starting inductance), nor will it necessarily equal the energy put in
(because of core saturation). A gapped inductor will be much more
linear, and much larger.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html

 

[Tim Wescott]

Gerbermultit00l@gmail.com wrote:

A product I am designing requires a series of lab tests to judge
robustness against electrical transients.

One such test is to charge up a 100mH inductor in series with a 4 ohm
load (4ohm load to ground). Then, once the inductor is fully charged,
open the supply current to it from the high side. The resulting field
collapse will produce a substantial negative going voltage spike.

The circuit goes V+ to switch to inductor to resistor to ground.

The DUT is placed in parallel with the inductor/resistor series
combination, at the open end of the circuit once the switch is opened.

My question: I want to prolong the duration of the pulse by a factor
of 10x to create a more destructive burst of energy.

E=.5*L*I^2

I want to keep DC current through the branch the same. With that
said, one would reason I would need to bump up my inductance by a
factor of 10. This would require a 1H inductor!

Is it practical to find such a large inductance? Any ideas?

Thank you

Gerb

What sort of transient voltages do you foresee? Could you get by with a
HV supply and a controller, or is that cheating?

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html

 

On Oct 2, 9:58 pm, "Phil Allison" <philalli...@tpg.com.au> wrote:

Gerbermultit...@gmail.com
"Phil Allison"







A product I am designing requires a series of lab tests to judge
robustness against electrical transients.

One such test is to charge up a 100mH inductor in series with a 4 ohm
load (4ohm load to ground). Then, once the inductor is fully charged,
open the supply current to it from the high side. The resulting field
collapse will produce a substantial negative going voltage spike.

The circuit goes V+ to switch to inductor to resistor to ground.

The DUT is placed in parallel with the inductor/resistor series
combination, at the open end of the circuit once the switch is opened..

My question: I want to prolong the duration of the pulse by a factor
of 10x to create a more destructive burst of energy.

E=.5*L*I^2

I want to keep DC current through the branch the same. With that
said, one would reason I would need to bump up my inductance by a
factor of 10. This would require a 1H inductor!

Is it practical to find such a large inductance? Any ideas?

** All depends on what DC current you are testing at.

Why not tell us ?

You know Phil, no matter how hard I try, I always end up leaving out
some vital detail.  Thanks for helping me out .

I would like to pass 3.2A +/- 200mA through the inductor.  I realize
that as the inductor gains in size, so will its series DC resistance.
Therefore, at one point I might need to adjust my series resistance to
keep the branch current where I want it.  This will result in a very
large inductor.  Digikey does not carry these .

**  Hmmmm  -

 a 3.5 amp rated inductor of say 1 Henry would weigh more than I care to
lift.

.....    Phil- Hide quoted text -

- Show quoted text -

I understand its not going to be small nor light wieght. However, I
need to come up with something in close proximity to what I require.
Ideas anyone?

Gerb

 

[Phil Allison]

"Tim Wescott"

I'd check out power transformer companies -- Hammond and Peter W. Dahl
come to mind.

** Hammond have inductors for high voltage PSUs of up to 10H - but none
come anywhere near the OP's 3.5 amp requirement.

You may be able to get something made custom, or find a power transformer
with a primary winding of around 1H.

** Nonsense.

Transformer primaries are NOT efficient inductors and will SATURATE long
before 3.5 amps is reached.

You may also be able to start with a big-iron power transformer and rewind
it for your 1H.

** Need to start with a tranny of several kW rating and the lams have to be
re-stacked to create an appropriate air gap.

Big job.


...... Phil

 

[Tim Wescott]

Phil Allison wrote:

"Tim Wescott"

I'd check out power transformer companies -- Hammond and Peter W. Dahl
come to mind.

** Hammond have inductors for high voltage PSUs of up to 10H - but none
come anywhere near the OP's 3.5 amp requirement.

"Check with" != "look in catalog like a twit".

"Check with" == "call nice Hammond lady on the phone and ask".

You may be able to get something made custom, or find a power transformer
with a primary winding of around 1H.


** Nonsense.

Transformer primaries are NOT efficient inductors and will SATURATE long
before 3.5 amps is reached.

Why thank you, Phil. It's so nice to be educated by you today.

So, there are no transformers anywhere in this wide world that can carry
3.5ADC without starting to SATURATE. Is 'SATURATE' the same as
'saturate', or is this some obscure technical term that I'm not familiar
with?

So those transformers that PGE uses, that are as big as a small house,
can't take 3.5ADC in any of their windings, and couldn't even if they
were rewound to 1H?

Gee. I learn something new every single day!

You may also be able to start with a big-iron power transformer and rewind
it for your 1H.


** Need to start with a tranny of several kW rating and the lams have to be
re-stacked to create an appropriate air gap.

Big job.

So?

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html

 

[Phil Allison]

"Tim Wescott Fuckwit "

I'd check out power transformer companies -- Hammond and Peter W. Dahl
come to mind.

** Hammond have inductors for high voltage PSUs of up to 10H - but
none come anywhere near the OP's 3.5 amp requirement.

"Check with" != "look in catalog like a twit".
"Check with" == "call nice Hammond lady on the phone and ask".

** Fuck you - you pathetic asshole.

You may be able to get something made custom, or find a power
transformer with a primary winding of around 1H.


** Nonsense.

Transformer primaries are NOT efficient inductors and will SATURATE
long before 3.5 amps is reached.


Why thank you, Phil. It's so nice to be educated by you today.

** Fuck you - you pathetic asshole.

So, there are no transformers anywhere in this wide world

** Fuck you - you pathetic asshole.

The OP has not got access to every tranny in the WHOLE world.

FUCKWIT !!!!

Is 'SATURATE' the same as 'saturate',

** Fuck you - you pathetic ASD fucked asshole.

So those transformers that PGE uses, that are as big as a small house,
can't take 3.5ADC in any of their windings, and couldn't even if they were
rewound to 1H?

** Fuck you - you pathetic ASD fucked asshole.

Gee. I learn something new every single day!

** Fuck you - you pathetic ASD fucked asshole.

You may also be able to start with a big-iron power transformer and
rewind it for your 1H.


** Need to start with a tranny of several kW rating and the lams have to
be re-stacked to create an appropriate air gap.

Big job.

So?

** The OP, like many who post here, did NOT need his idiotic Q answering in
the LITERAL way ASD fucked morons like YOU always do.

He needs to think of another way to do his test.

While YOU need to get a brain transplant - even a chimp's brain would be
an improvement.




...... Phil

 

[Bob Masta]

On Tue, 30 Sep 2008 08:45:17 -0700 (PDT),
Gerbermultit00l@gmail.com wrote:

A product I am designing requires a series of lab tests to judge
robustness against electrical transients.

One such test is to charge up a 100mH inductor in series with a 4 ohm
load (4ohm load to ground). Then, once the inductor is fully charged,
open the supply current to it from the high side. The resulting field
collapse will produce a substantial negative going voltage spike.

The circuit goes V+ to switch to inductor to resistor to ground.

The DUT is placed in parallel with the inductor/resistor series
combination, at the open end of the circuit once the switch is opened.

My question: I want to prolong the duration of the pulse by a factor
of 10x to create a more destructive burst of energy.

E=.5*L*I^2

I want to keep DC current through the branch the same. With that
said, one would reason I would need to bump up my inductance by a
factor of 10. This would require a 1H inductor!

Is it practical to find such a large inductance? Any ideas?

Do you really need the inductance circuit to test
the DUT? If you want a more destructive pulse,
how about creating the shape you want with an
arbitrary waveform generator or even with your
original inductor circuit, then using it to
control a big amp or power supply applied to your
DUT?

Best regards,


Bob Masta

DAQARTA v4.50
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Scope, Spectrum, Spectrogram, Sound Level Meter
FREE Signal Generator
Science with your sound card!

 

[John Fields]

On Tue, 7 Oct 2008 13:24:08 -0700 (PDT), Gerbermultit00l@gmail.com
wrote:

On Oct 6, 12:23 pm, Tim Wescott <t...@seemywebsite.com> wrote:
Gerbermultit...@gmail.com wrote:
A product I am designing requires a series of lab tests to judge
robustness against electrical transients.

One such test is to charge up a 100mH inductor in series with a 4 ohm
load (4ohm load to ground).  Then, once the inductor is fully charged,
open the supply current to it from the high side.  The resulting field
collapse will produce a substantial negative going voltage spike.

The circuit goes V+ to switch to inductor to resistor to ground.

The DUT is placed in parallel with the inductor/resistor series
combination, at the open end of the circuit once the switch is opened.

My question:  I want to prolong the duration of the pulse by a factor
of 10x to create a more destructive burst of energy.

E=.5*L*I^2

I want to keep DC current through the branch the same.  With that
said, one would reason I would need to bump up my inductance by a
factor of 10.  This would require a 1H inductor!

Is it practical to find such a large inductance?  Any ideas?

Thank you

Gerb

What sort oftransientvoltages do you foresee?  Could you get by with a
HV supply and a controller, or is that cheating?

--

Tim Wescott
Wescott Design Serviceshttp://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details athttp://www.wescottdesign.com/actfes/actfes.html- Hide quoted text -

- Show quoted text -

I want to create a -400V transient (switching the inductor high side)
with a time contant of approximately 10mS. I have the option of
taking this to a local EMC lab that has the capability of generating
this pulse. However, I might want to run a few hundred products
through this test. EMC lab time is expensive. For reasons I would
rather not go into, I'd like to do this "on the cheap side". Thus,
building my own equipment from scratch and surplus bits.

I found two companies willing to construct inductors for me. The
problem, the cheaper of the two wanted $2500USD. I currently don't
have that type of budget. I assume the solution you mentioed above
(High voltage supply and controller) will cost even more.

---
Why don't you charge a cap up to -400V and dump that into your DUT?

JF

 

On Oct 6, 12:23 pm, Tim Wescott <t...@seemywebsite.com> wrote:

Gerbermultit...@gmail.com wrote:
A product I am designing requires a series of lab tests to judge
robustness against electrical transients.

One such test is to charge up a 100mH inductor in series with a 4 ohm
load (4ohm load to ground).  Then, once the inductor is fully charged,
open the supply current to it from the high side.  The resulting field
collapse will produce a substantial negative going voltage spike.

The circuit goes V+ to switch to inductor to resistor to ground.

The DUT is placed in parallel with the inductor/resistor series
combination, at the open end of the circuit once the switch is opened.

My question:  I want to prolong the duration of the pulse by a factor
of 10x to create a more destructive burst of energy.

E=.5*L*I^2

I want to keep DC current through the branch the same.  With that
said, one would reason I would need to bump up my inductance by a
factor of 10.  This would require a 1H inductor!

Is it practical to find such a large inductance?  Any ideas?

Thank you

Gerb

What sort oftransientvoltages do you foresee?  Could you get by with a
HV supply and a controller, or is that cheating?

--

Tim Wescott
Wescott Design Serviceshttp://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says..
See details athttp://www.wescottdesign.com/actfes/actfes.html- Hide quoted text -

- Show quoted text -

I want to create a -400V transient (switching the inductor high side)
with a time contant of approximately 10mS. I have the option of
taking this to a local EMC lab that has the capability of generating
this pulse. However, I might want to run a few hundred products
through this test. EMC lab time is expensive. For reasons I would
rather not go into, I'd like to do this "on the cheap side". Thus,
building my own equipment from scratch and surplus bits.

I found two companies willing to construct inductors for me. The
problem, the cheaper of the two wanted $2500USD. I currently don't
have that type of budget. I assume the solution you mentioed above
(High voltage supply and controller) will cost even more.

Thank you,

Gerb

 

On Oct 7, 9:18 am, N0S...@daqarta.com (Bob Masta) wrote:

On Tue, 30 Sep 2008 08:45:17 -0700 (PDT),





Gerbermultit...@gmail.com wrote:
A product I am designing requires a series of lab tests to judge
robustness against electrical transients.

One such test is to charge up a 100mH inductor in series with a 4 ohm
load (4ohm load to ground).  Then, once the inductor is fully charged,
open the supply current to it from the high side.  The resulting field
collapse will produce a substantial negative going voltage spike.

The circuit goes V+ to switch to inductor to resistor to ground.

The DUT is placed in parallel with the inductor/resistor series
combination, at the open end of the circuit once the switch is opened.

My question:  I want to prolong the duration of the pulse by a factor
of 10x to create a more destructive burst of energy.

E=.5*L*I^2

I want to keep DC current through the branch the same.  With that
said, one would reason I would need to bump up my inductance by a
factor of 10.  This would require a 1H inductor!

Is it practical to find such a large inductance?  Any ideas?

Do you really need the inductance circuit to test
the DUT?  If you want a more destructive pulse,
how about creating the shape you want with an
arbitrary waveform generator or even with your
original inductor circuit, then using it to
control a big amp or power supply applied to your
DUT?

Best regards,

Bob Masta

              DAQARTA  v4.50
   Data AcQuisition And Real-Time Analysis
             www.daqarta.com
Scope, Spectrum, Spectrogram, Sound Level Meter
           FREE Signal Generator
        Science with your sound card!- Hide quoted text -

- Show quoted text -

I've looked into what the equipment I would need to do this would
cost. It is just not feasible.

 

[Tim Wescott]

Phil Allison wrote:

"Tim Wescott Fuckwit "

I'd check out power transformer companies -- Hammond and Peter W. Dahl
come to mind.
** Hammond have inductors for high voltage PSUs of up to 10H - but
none come anywhere near the OP's 3.5 amp requirement.
"Check with" != "look in catalog like a twit".
"Check with" == "call nice Hammond lady on the phone and ask".


** Fuck you - you pathetic asshole.

You're very generous, but it's a long flight to Oz (and quite frankly
you're just not my type).

You may be able to get something made custom, or find a power
transformer with a primary winding of around 1H.

** Nonsense.

Transformer primaries are NOT efficient inductors and will SATURATE
long before 3.5 amps is reached.

Why thank you, Phil. It's so nice to be educated by you today.


** Fuck you - you pathetic asshole.

Is something bothering you today, Phil?

So, there are no transformers anywhere in this wide world


** Fuck you - you pathetic asshole.

The OP has not got access to every tranny in the WHOLE world.

FUCKWIT !!!!

Repeat after me: "Surplus is cheap." "Surplus is cheap."

Is 'SATURATE' the same as 'saturate',


** Fuck you - you pathetic ASD fucked asshole.

Oh! Variety!

So those transformers that PGE uses, that are as big as a small house,
can't take 3.5ADC in any of their windings, and couldn't even if they were
rewound to 1H?


** Fuck you - you pathetic ASD fucked asshole.

Getting a bit repetitive, there, Phil.

Gee. I learn something new every single day!


** Fuck you - you pathetic ASD fucked asshole.

Getting _really_ repetitive, there, Phil.

You may also be able to start with a big-iron power transformer and
rewind it for your 1H.

** Need to start with a tranny of several kW rating and the lams have to
be re-stacked to create an appropriate air gap.

Big job.
So?


** The OP, like many who post here, did NOT need his idiotic Q answering in
the LITERAL way ASD fucked morons like YOU always do.

Hells bells and little birdies, Phil, you need to get a Thesaurus of
Vulgar Words. Otherwise you'll get boring.

He needs to think of another way to do his test.

Sometimes, for a one-off bit of kit, doing it "the hard way" is the
easiest way in the world. So maybe doing the test just the way he wants
to is exactly the right thing to do. I'm willing let him use _his_
judgment as to whether he's taking the right approach, rather than
attempting to ram (via USENET no less!) my own narrow world view down
his throat.

While YOU need to get a brain transplant - even a chimp's brain would be
an improvement.

Could you please find a way to insult me in ways that use words that
sound like other words? Then I could say that you engaged in an ad
homonym attack.

That would be pun.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html

 

[Tim Wescott]

John Fields wrote:

On Tue, 7 Oct 2008 13:24:08 -0700 (PDT), Gerbermultit00l@gmail.com
wrote:

On Oct 6, 12:23 pm, Tim Wescott <t...@seemywebsite.com> wrote:
Gerbermultit...@gmail.com wrote:
A product I am designing requires a series of lab tests to judge
robustness against electrical transients.
One such test is to charge up a 100mH inductor in series with a 4 ohm
load (4ohm load to ground). Then, once the inductor is fully charged,
open the supply current to it from the high side. The resulting field
collapse will produce a substantial negative going voltage spike.
The circuit goes V+ to switch to inductor to resistor to ground.
The DUT is placed in parallel with the inductor/resistor series
combination, at the open end of the circuit once the switch is opened.
My question: I want to prolong the duration of the pulse by a factor
of 10x to create a more destructive burst of energy.
E=.5*L*I^2
I want to keep DC current through the branch the same. With that
said, one would reason I would need to bump up my inductance by a
factor of 10. This would require a 1H inductor!
Is it practical to find such a large inductance? Any ideas?
Thank you
Gerb
What sort oftransientvoltages do you foresee? Could you get by with a
HV supply and a controller, or is that cheating?

--

Tim Wescott
Wescott Design Serviceshttp://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details athttp://www.wescottdesign.com/actfes/actfes.html- Hide quoted text -

- Show quoted text -
I want to create a -400V transient (switching the inductor high side)
with a time contant of approximately 10mS. I have the option of
taking this to a local EMC lab that has the capability of generating
this pulse. However, I might want to run a few hundred products
through this test. EMC lab time is expensive. For reasons I would
rather not go into, I'd like to do this "on the cheap side". Thus,
building my own equipment from scratch and surplus bits.

I found two companies willing to construct inductors for me. The
problem, the cheaper of the two wanted $2500USD. I currently don't
have that type of budget. I assume the solution you mentioed above
(High voltage supply and controller) will cost even more.

---
Why don't you charge a cap up to -400V and dump that into your DUT?

JF

3.5A at 400V from a cap may work better than the same amount of energy
from a coil.

It's just no the same if the load is non resistive, of course.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html

 

[Tim Wescott]

Gerbermultit00l@gmail.com wrote:

On Oct 6, 12:23 pm, Tim Wescott <t...@seemywebsite.com> wrote:
Gerbermultit...@gmail.com wrote:
A product I am designing requires a series of lab tests to judge
robustness against electrical transients.
One such test is to charge up a 100mH inductor in series with a 4 ohm
load (4ohm load to ground). Then, once the inductor is fully charged,
open the supply current to it from the high side. The resulting field
collapse will produce a substantial negative going voltage spike.
The circuit goes V+ to switch to inductor to resistor to ground.
The DUT is placed in parallel with the inductor/resistor series
combination, at the open end of the circuit once the switch is opened.
My question: I want to prolong the duration of the pulse by a factor
of 10x to create a more destructive burst of energy.
E=.5*L*I^2
I want to keep DC current through the branch the same. With that
said, one would reason I would need to bump up my inductance by a
factor of 10. This would require a 1H inductor!
Is it practical to find such a large inductance? Any ideas?
Thank you
Gerb
What sort oftransientvoltages do you foresee? Could you get by with a
HV supply and a controller, or is that cheating?

--

Tim Wescott
Wescott Design Serviceshttp://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details athttp://www.wescottdesign.com/actfes/actfes.html- Hide quoted text -

- Show quoted text -

I want to create a -400V transient (switching the inductor high side)
with a time contant of approximately 10mS. I have the option of
taking this to a local EMC lab that has the capability of generating
this pulse. However, I might want to run a few hundred products
through this test. EMC lab time is expensive. For reasons I would
rather not go into, I'd like to do this "on the cheap side". Thus,
building my own equipment from scratch and surplus bits.

I found two companies willing to construct inductors for me. The
problem, the cheaper of the two wanted $2500USD. I currently don't
have that type of budget. I assume the solution you mentioed above
(High voltage supply and controller) will cost even more.

Thank you,

Gerb

The opinion of certain vulgar individuals notwithstanding, I still think
it's worth looking into kit-bashing a transformer. For $2500 you can
spend a considerable amount of time rebuilding and rewinding a surplus
core and still come out ahead.

I'd look to the coils that Hammond sells purely for the purpose of
getting a weight vs. energy number, then think about (a) whether I want
that big of a lump of steel cluttering up my shop, and (b) where in heck
I could get a core that big for cheap.

Come to think of it, why look for one great gazonga of a thing, when you
can build it yourself out of smaller chokes?

Just from the Antique Radio Supply catalog, I see that you could put
together 10 10H x 500mA chokes in parallel for a 1H, 5A choke. It'd
weigh 210lbs less your frame, and cost you 10 x $68.45. That's a heck
of a lot less than your $2500. Hammond also has a 100mH, 5A, 14lb choke
(the 195T5) that you could string in series, but Antique Radio Supply
doesn't list it (and if you're getting 10, you'd be better off getting
it straight from Hammond anyway).

Check to make sure you're not getting a "swinging" choke, unless a
swinging choke is what you want.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html

 

[Phil Allison]

"Tim Wescott PIG ARROGANT Fuckwit "

** The OP, like many who post here, did NOT need his idiotic Q answering
in the LITERAL way ASD fucked morons like YOU always do.

Hells bells and little birdies,

** What a fucking ARSEWIPE you are - Wescuntt.

He needs to think of another way to do his test.

Sometimes,

** What is sometimes the case is not THIS time !

All you ever SPEW is irrelevant & IRRATIONAL SHIT !!

I'm willing let him use _his_ judgment as to whether he's taking the
right approach,

** Spoken like a completely narcissistic FOOL.

All you are Wescuntt is a CLUELESS TWAT

dishing out 100 % STUPID advice.


YOU need to get a brain transplant - even a DEAD chimp's brain would be
an improvement.

Piss off - TURD BRAIN !!!




....... Phil

 

[Michael A. Terrell]

Gerbermultit00l@gmail.com wrote:

On Oct 8, 2:12 am, "Phil Allison" <philalli...@tpg.com.au> wrote:
"Tim Wescott PIG ARROGANT Fuckwit "



** The OP, like many who post here, did NOT need his idiotic Q answering
in the LITERAL way ASD fucked morons like YOU always do.

Hells bells and little birdies,

** What a fucking ARSEWIPE you are - Wescuntt.

He needs to think of another way to do his test.

Sometimes,

** What is sometimes the case is not THIS time !

All you ever SPEW is irrelevant & IRRATIONAL SHIT !!

I'm willing let him use _his_ judgment as to whether he's taking the
right approach,

** Spoken like a completely narcissistic FOOL.

All you are Wescuntt is a CLUELESS TWAT

dishing out 100 % STUPID advice.

YOU need to get a brain transplant - even a DEAD chimp's brain would be
an improvement.

Piss off - TURD BRAIN !!!

...... Phil

Gentlemen. May I ask why this thread has turned into nothing but one
big pissing match? It seems you don't have much respect for each
other. That is OK. But please take the arguement elsewhere.

Phil is mentally ill, and doesn't take his medication. He's been
like this for years, and rarely has anything useful to add to a thread.
People with a real news server generally kill file him.


--
http://improve-usenet.org/index.html

aioe.org, Goggle Groups, and Web TV users must request to be white
listed, or I will not see your messages.

If you have broadband, your ISP may have a NNTP news server included in
your account: http://www.usenettools.net/ISP.htm


There are two kinds of people on this earth:
The crazy, and the insane.
The first sign of insanity is denying that you're crazy.

 

On Oct 7, 4:44 pm, John Fields <jfie...@austininstruments.com> wrote:

On Tue, 7 Oct 2008 13:24:08 -0700 (PDT), Gerbermultit...@gmail.com
wrote:





On Oct 6, 12:23 pm, Tim Wescott <t...@seemywebsite.com> wrote:
Gerbermultit...@gmail.com wrote:
A product I am designing requires a series of lab tests to judge
robustness against electrical transients.

One such test is to charge up a 100mH inductor in series with a 4 ohm
load (4ohm load to ground).  Then, once the inductor is fully charged,
open the supply current to it from the high side.  The resulting field
collapse will produce a substantial negative going voltage spike.

The circuit goes V+ to switch to inductor to resistor to ground.

The DUT is placed in parallel with the inductor/resistor series
combination, at the open end of the circuit once the switch is opened.

My question:  I want to prolong the duration of the pulse by a factor
of 10x to create a more destructive burst of energy.

E=.5*L*I^2

I want to keep DC current through the branch the same.  With that
said, one would reason I would need to bump up my inductance by a
factor of 10.  This would require a 1H inductor!

Is it practical to find such a large inductance?  Any ideas?

Thank you

Gerb

What sort oftransientvoltages do you foresee?  Could you get by with a
HV supply and a controller, or is that cheating?

--

Tim Wescott
Wescott Design Serviceshttp://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details athttp://www.wescottdesign.com/actfes/actfes.html-Hide quoted text -

- Show quoted text -

I want to create a -400V transient (switching the inductor high side)
with a time contant of approximately 10mS.  I have the option of
taking this to a local EMC lab that has the capability of generating
this pulse.  However, I might want to run a few hundred products
through this test.  EMC lab time is expensive.  For reasons I would
rather not go into, I'd like to do this "on the cheap side".  Thus,
building my own equipment from scratch and surplus bits.

I found two companies willing to construct inductors for me.  The
problem, the cheaper of the two wanted $2500USD.  I currently don't
have that type of budget.  I assume the solution you mentioed above
(High voltage supply and controller) will cost even more.

---
Why don't you charge a cap up to -400V and dump that into your DUT?

JF- Hide quoted text -

- Show quoted text -

Dooohhhh! Interesting...

Gerb