Hi all,
I need to switch high voltage (1kV at 2kHz AC), low current to
sequence some electro luminescent wires. I'm working on the trigger
sequencer and I have the high voltage/ high frequency PSU but I'm not
sure what kind of device/technique to use for the actual switching
between 5 channels. Any suggestions greatfully received.
Thanks in advance,
UK Pete

UK Pete wrote:
Hi all,
I need to switch high voltage (1kV at 2kHz AC), low current to
sequence some electro luminescent wires. I'm working on the trigger
sequencer and I have the high voltage/ high frequency PSU but I'm not
sure what kind of device/technique to use for the actual switching
between 5 channels. Any suggestions greatfully received.
Thanks in advance,
UK Pete

... Ooops Make that 200V AC @ 2kHz...

"UK Pete" wrote in message
oups.com...

UK Pete wrote:
Hi all,
I need to switch high voltage (1kV at 2kHz AC), low current to
sequence some electro luminescent wires. I'm working on the trigger
sequencer and I have the high voltage/ high frequency PSU but I'm not
sure what kind of device/technique to use for the actual switching
between 5 channels. Any suggestions greatfully received.
Thanks in advance,
UK Pete

.. Ooops Make that 200V AC @ 2kHz...


Is the switching rate 2kHz or is the AC frequency 2kHz?


--
Dan Hollands
1120 S Creek Dr
Webster NY 14580
585-872-2606

www.QuickScoreRace.com

On 31 Jan 2006 06:40:31 -0800, "UK Pete"
wrote:


UK Pete wrote:
Hi all,
I need to switch high voltage (1kV at 2kHz AC), low current to
sequence some electro luminescent wires. I'm working on the trigger
sequencer and I have the high voltage/ high frequency PSU but I'm not
sure what kind of device/technique to use for the actual switching
between 5 channels. Any suggestions greatfully received.
Thanks in advance,
UK Pete

.. Ooops Make that 200V AC @ 2kHz...

---
http://www.clare.com/home/pdfs.nsf/www/LCA110L_R1_0.qxd.pdf/$file/LCA110L_R1_0.qxd.pdf

Or, check this page for a lot of choices:

http://www.clare.com/Products/SSR.htm

Also: IR, Aromat(NAIS), or google "solid state rerlay"


--
John Fields
Professional Circuit Designer

Sorry Dan, I should have made that clear. The AC is 2 kHz but the
switching speed is only up to 20Hz and it looks like John has found the
ideal component. The only problem is I can't find a supplier that
doesn't sell them by the dozen or so. I can't even find a price on
them. I want to ideally keep the cost low as possible.
Thanks for the replies!

UK Pete

On 31 Jan 2006 12:51:08 -0800, "UK Pete"
wrote:

Sorry Dan, I should have made that clear. The AC is 2 kHz but the
switching speed is only up to 20Hz and it looks like John has found the
ideal component. The only problem is I can't find a supplier that
doesn't sell them by the dozen or so. I can't even find a price on
them. I want to ideally keep the cost low as possible.
Thanks for the replies!

---
In the UK, Clare lists their distributors as:

Mr Tom Paul
AX Distribution
Unit 22 Lawson Hunt Ind. Park
Broadbridge Heath
Horsham RH12 3JR,
United Kingdom
CountryCode: 44
Phone: (01) 403-240055
Fax: (01) 403-255657

http://www.axdistribution.com

Future Electronics - United Kingdom
Future House, Poyle Road
Colnbrook
Berks SL3 OEZ,
United Kingdom
CountryCode: 44
Phone: (01) 753-763000
Fax: (01) 753-689100

http://www.futureelectronics.com

---
In the US, Mouser:

http://www.mouser.com/

Sells them with no mimimum quantity, and they're less than a couple
of dollars apiece, I think. Check their catalog at:

http://www.mouser.com/catalog/625/1308.pdf


--
John Fields
Professional Circuit Designer

On 2006-01-31, UK Pete wrote:

UK Pete wrote:
Hi all,
I need to switch high voltage (1kV at 2kHz AC), low current to
sequence some electro luminescent wires. I'm working on the trigger
sequencer and I have the high voltage/ high frequency PSU but I'm not
sure what kind of device/technique to use for the actual switching
between 5 channels. Any suggestions greatfully received.
Thanks in advance,
UK Pete

.. Ooops Make that 200V AC @ 2kHz...

MOC3021 (upto 100mA) If you're in the UK that part (or similar) should be readily
available, it's an optocoupler used to drive triacs but also seems suitable to
switching 200VAC at low currents.

Bye.
Jasen

On Wed, 01 Feb 2006 09:04:18 -0000, Jasen Betts
wrote:

On 2006-01-31, UK Pete wrote:

UK Pete wrote:
Hi all,
I need to switch high voltage (1kV at 2kHz AC), low current to
sequence some electro luminescent wires. I'm working on the trigger
sequencer and I have the high voltage/ high frequency PSU but I'm not
sure what kind of device/technique to use for the actual switching
between 5 channels. Any suggestions greatfully received.
Thanks in advance,
UK Pete

.. Ooops Make that 200V AC @ 2kHz...

MOC3021 (upto 100mA) If you're in the UK that part (or similar) should be readily
available, it's an optocoupler used to drive triacs but also seems suitable to
switching 200VAC at low currents.

---
I don't think so.

His 200V drive is almost for sure going to be coming from an
inverter with a rectangular output waveform.

Take a look at pages 4 and 5 of:

http://www.fairchildsemi.com/ds/MO%2FMOC3021-M.pdf


--
John Fields
Professional Circuit Designer

On 2006-02-01, John Fields wrote:

Hi all,
I need to switch high voltage (1kV at 2kHz AC), low current to
sequence some electro luminescent wires. I'm working on the trigger
sequencer and I have the high voltage/ high frequency PSU but I'm not
sure what kind of device/technique to use for the actual switching
between 5 channels. Any suggestions greatfully received.
Thanks in advance,
UK Pete

.. Ooops Make that 200V AC @ 2kHz...

MOC3021 (upto 100mA) If you're in the UK that part (or similar) should be readily
available, it's an optocoupler used to drive triacs but also seems suitable to
switching 200VAC at low currents.

I don't think so.

His 200V drive is almost for sure going to be coming from an
inverter with a rectangular output waveform.

and that'll be a problem ?
could it be solved using some sort of low-pass filter?

Take a look at pages 4 and 5 of:

I'm not sure what to look for
I see a curve for on voltage that puts it at around 1.5 for 100mA
150mW is well within the reasonable range.

I see figure 5, and the circuit top of page 5

200vX200Khz 80000V/s = 0.08V/us if a triangle wave
more if a sine wave, yet more if a square wave.
but with a square wave would switching on a little late be a problem?

Is a solid state relay likely to perform better?

http://www.fairchildsemi.com/ds/MO%2FMOC3021-M.pdf

thanks for searching that out, I'd misplaced my copy and was looking at a
summary in a paper catalogue.


I see the bit that says "This optocoupler should not be used to drive a load
directly, it is intended to be a trigger device only."

But these electroluminescent wires only draw a few milliamps it's not like
trying to switch a lightbulb where the cold current can be a few amps.

What am I missing?


--

Bye.
Jasen

On Thu, 02 Feb 2006 10:15:23 -0000, Jasen Betts
wrote:

On 2006-02-01, John Fields wrote:

Hi all,
I need to switch high voltage (1kV at 2kHz AC), low current to
sequence some electro luminescent wires. I'm working on the trigger
sequencer and I have the high voltage/ high frequency PSU but I'm not
sure what kind of device/technique to use for the actual switching
between 5 channels. Any suggestions greatfully received.
Thanks in advance,
UK Pete

.. Ooops Make that 200V AC @ 2kHz...

MOC3021 (upto 100mA) If you're in the UK that part (or similar) should be readily
available, it's an optocoupler used to drive triacs but also seems suitable to
switching 200VAC at low currents.

I don't think so.

His 200V drive is almost for sure going to be coming from an
inverter with a rectangular output waveform.

and that'll be a problem ?
could it be solved using some sort of low-pass filter?

---
Not likely, since the color and, to a lesser extent, the intensity
of the light coming from the EL wires will change if the waveshape
of the signal driving them changes.

But, the point is, why bother?

Using a proper SSR will preserve the shape of the driving signal and
eliminate the possibility of any commutation problems which might
come up using a thyristor switch.
---

Take a look at pages 4 and 5 of:

I'm not sure what to look for
I see a curve for on voltage that puts it at around 1.5 for 100mA
150mW is well within the reasonable range.

I see figure 5, and the circuit top of page 5

200vX200Khz 80000V/s = 0.08V/us if a triangle wave
more if a sine wave, yet more if a square wave.

---
You're reading it wrong. Notice that at 20C the maximum rate of
change is 10V/µs. That means that if you try to switch a signal
which goes from zero volts to ten volts in one microsecond you'll be
OK, but if you try to switch a signal which goes from zero volts to
eleven volts in a microsecond, you won't.

That means that for the OP's signal, which is making 200 volt
transitions, those transitions need to take longer than 20µs for
commutation not to occur.
---

but with a square wave would switching on a little late be a problem?

---
No, commutation would.
---

Is a solid state relay likely to perform better?

---
Yes.

With a solid state relay there will be no commutation problems.
---

http://www.fairchildsemi.com/ds/MO%2FMOC3021-M.pdf

thanks for searching that out, I'd misplaced my copy and was looking at a
summary in a paper catalogue.


I see the bit that says "This optocoupler should not be used to drive a load
directly, it is intended to be a trigger device only."

But these electroluminescent wires only draw a few milliamps it's not like
trying to switch a lightbulb where the cold current can be a few amps.

What am I missing?

---
Even with a resistive load, the rate of change of the signal out of
the inverter, when it switches, is likely to turn on the bilateral
switch whether the LED is on or not. With a capacitive load (EL
wires look like lossy capacitors) the problem will be aggravated
aggravated.

Try this link:

http://www.onsemi.com/pub/Collateral/HBD855-D.PDF


--
John Fields
Professional Circuit Designer

Wow. Thanks for all the thought and time taken to post replies!
I looked at the waveform from the inverter on a 'scope and found it to
be nearer 130V and around 5kHz which wasn not as it was specified to
me. The waveform appeared not too far off sinusoidal which I was
surprised at. I also found some MOC 3020s on Ebay and paid just 18
pence each for them so I'll give them a go anyway.
Let me know if you want a couple of them to play with and I'll stick
'em in the post for free.
Thanks again,

UK Pete

On 3 Feb 2006 06:27:02 -0800, "UK Pete" wrote:


Wow. Thanks for all the thought and time taken to post replies!
I looked at the waveform from the inverter on a 'scope and found it to
be nearer 130V and around 5kHz which wasn not as it was specified to
me. The waveform appeared not too far off sinusoidal which I was
surprised at. I also found some MOC 3020s on Ebay and paid just 18
pence each for them so I'll give them a go anyway.
Let me know if you want a couple of them to play with and I'll stick
'em in the post for free.
Thanks again,

---
You're welcome, and thanks for the offer, I'll take it!

I'll email you my physical address.


--
John Fields
Professional Circuit Designer