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EL wire and high voltage AC switching question
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 |
EL wire and high voltage AC switching question
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... |
EL wire and high voltage AC switching question
"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 |
EL wire and high voltage AC switching question
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 |
EL wire and high voltage AC switching question
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 |
EL wire and high voltage AC switching question
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 |
EL wire and high voltage AC switching question
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 |
EL wire and high voltage AC switching question
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 |
EL wire and high voltage AC switching question
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 |
EL wire and high voltage AC switching question
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 |
EL wire and high voltage AC switching question
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 |
EL wire and high voltage AC switching question
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 |
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