Any reccommendations on a cap size? I already planned on having a big mambajamba in there make sure It will jump across air if given the opportunity.

Sparks in air need between 5k-10k volts to jump 1 inch of air. 1kV will jump about a 1mm gap.

 

Sparks in air need between 5k-10k volts to jump 1 inch of air. 1kV will jump about a 1mm gap.

So I need to up my voltage. I don't know how far I can go though because we only hipot test the cables to 3800V. darn, back to the drawing board/

 

strantor - is this test equipment to measure compliance to a standard, or do you have some kind of specification or achievement for this tester?

A standard megger test function (which is what this is looking like, given the very low current availability) is usually only to 1kV, and is conducted prior and post a hipot test (which may be at a significantly higher voltage level).

 

strantor - is this test equipment to measure compliance to a standard, or do you have some kind of specification or achievement for this tester?

A standard megger test function (which is what this is looking like, given the very low current availability) is usually only to 1kV, and is conducted prior and post a hipot test (which may be at a significantly higher voltage level).

No, not testing for compliance to a standard.
Yes, this cable gets megger'd and hipot'd (3800v) before and megger'd after this phase of production (having thick steel armor wire twisted onto the outside of it). The purpose of this device is to detect if the cable becomes damaged during this phase, so that the machine can be stopped, problem corrected, and continue without waiting until the entire length has run through and a problem discovered in the middle.

The damages we are looking for are opens in the conductors, direct shorts, indirect shorts (air gaps=insulation rubbed off/snagged etc, or thin/compressed/almost severed insulation).

We need to test continuity of the conductors and leakage at the same time. I had planned on using the 1kv as a continuity check as well as a leakage detector. I needed higher wattage output because of the resistive voltage divider that I was using to step the 1KV down to 3V to light my "continuity OK" LEDs. Now now I am thinking that maybe I could have a lower voltage continuity test running on my conductors at the same time as I have a 1KV leakage detection going on (so long as I keep the grounds separate). What do you think? I will make another post about this separate topic later.

Thanks!

 

Why not use neon lights? They draw almost no current and aren't nearly as picky about voltage as LEDs.

 

Why not use neon lights? They draw almost no current and aren't nearly as picky about voltage as LEDs.

I said LEDs when I should have said optoisolators. Right now in the planning phase I am using a crude optoisolator made out of an LED and a photoresistor inside a piece of shrink tubing. I planned on using legit optoisolators in the final product. Do they make neon optoislators?

 

Why not use neon lights? They draw almost no current and aren't nearly as picky about voltage as LEDs.

I'm looking here at data sheets for neon lights and I see "maximum breakdown voltage", for example 95V, then at the bottom of the sheet it reccommends to use at least 150v. so is "breakdown voltage" referring to the neon inside the bulb, as in what voltage the neon will break down and conduct and produce light? If so, why is called "MAXIMUM breakdown voltage", shouldn't it be MINIMUM? and if that is the minimum, what is the max? I'm confused.

 

The voltage is the point where they "breakdown", and do not allow a higher voltage across the terminals. Sort of like the LEDs "turn on voltage". Usually, a large resistor (1MΩ) is in series with the bulb to limit current, it will drop the voltage that the neon bulb wouldn't.

Due to their reddish orange ouput, a photodiode should react to their color, but specially phosphor coated neon bulbs can give any color from UV to short IR, one of which is sure to work in your application.

I don't believe they are packaged in an IC format as an opto-isolator, but the need for such an item exists, though I haven't worked directly with HV in quite a while.

 

If the only reason you want higher wattage (aka multiple dc/dc in parallel) is measurement detection, then I suggest firstly checking on a more sensitive sensing circuit. Given that you have a common ground for your HV, then you could use a higher resistance divider for analog voltage sensing, or even a current sense resistance and amplifier for current sensing. You could set up comparator driven LEDs for local indication. If you then want to isolate those analog levels you could put them through standard commercial signal isolators.

 

The datasheet shows that the output is not isolated - they are three terminal devices. So no, their outputs cannot be connected in series, but it is likely the outputs can be paralleled but that is not specifically stated in the datasheet (eg. email the manufacturer).

Hello Charlie

It certainly is not recommended as the units do not have any current control loops. Therefore one unit would try to feed all the load and just get hot and eventually blow.

Any way of limiting the current per unit would just use up more of the current available so by cutting what was left to feed the load

There is a 3 watt unit our PPM3 range. These are 1000V and tightly controlled units. I have attached a data sheet for you.

We do not currently have stock of them, please let me know how many you would need?

The unit price is £172.00 for 1-9
Delivery approx 10 weeks because of the Christmas holidays.

Other than that we jump to 10 watts and a larger footprint altogether

Regards

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Product Manager
HiTek Power

+44 (0)1903 712400 tel:
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Sent: 04 December 2010 16:02

Subject: Connecting multiple GMA12-1000p outputs in parallel

I have need for 1000v at higher output wattage than 1 unit can deliver. I want to connect 2 of them with the outputs in parallel to double the wattage. Is this possible? Recommended?

Thank you!

 

If the only reason you want higher wattage (aka multiple dc/dc in parallel) is measurement detection, then I suggest firstly checking on a more sensitive sensing circuit. Given that you have a common ground for your HV, then you could use a higher resistance divider the resistance divider value that I am using for my math is 1.5MΩ/3.8KΩ to output 2.5V. I think that if I were to go any higher than that I would not have enough current left to do anything useful. for analog voltage sensing For continuity I'm really only looking for a digital indicationof whether voltage is present or not, and I'm sure there has got to be a better way to do it than voltage dividers(but I'm not sure what that is)., or even a current sense resistance and amplifier for current sensing. You could set up comparator driven LEDs for local indication. If you then want to isolate those analog levels you could put them through standard commercial signal isolators The rest of this I will have to research and get back with you, as it was mostly over my head. .

Thanks again timrobbins!