Fluke 5200A as source? - Page 1
Forum section: electronics / testgear

author: maginnovision
author_rank: Super Contributor
timestamp: March 30, 2019, 06:31:17 am
content: Let's ignore safety and reasonableness for a second... Can the fluke 5200A outputting 120Vac drive a transformer to give closer to 500v(or 480) at ~50kHz or whatever frequency is chosen?

author: beanflying
author_rank: Super Contributor
timestamp: March 30, 2019, 07:10:23 am
content: Possible but ugly and very limited in current but possibly ok if you just want a transfer standard for Calibration use but then is gets uglier I suspect with error sources. Start saving your pennies for a 52xx Power Amp.

author: maginnovision
author_rank: Super Contributor
timestamp: March 30, 2019, 07:41:14 am
content: Yea, I think you get the idea. I don't have the space for the power amp, or the way to move it around when the situation arises. If I did I'd buy one right now, haha. I was considering building a couple of "Safe" boxes for higher voltages(low/high frequency) in a compact form. I don't know if 60Hz transformers would work at those frequencies but I suspect the current being so limited the heat might not be an issue. Alternatively 400hz, or custom transformers.

author: beanflying
author_rank: Super Contributor
timestamp: March 30, 2019, 07:49:47 am
content: Take a look at the circuit diagrams and description of operation for the Valhalla 2703 for some possible ideas on the higher voltages.https://valhallascientific.com/wp-content/uploads/2018/09/2703_2705_Manual.pdfHappy with my 2703 without the extra bulk of a Power Amp

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: March 30, 2019, 07:53:55 am
content: Hi,I had a quick look at the datasheet for the Fluke 5200. The maximum output current on the 100V range is 50mA.It is going to be hard to construct a wide band transformer for this application.Regards,Jay_Diddy_B

author: maginnovision
author_rank: Super Contributor
timestamp: March 30, 2019, 08:00:20 am
content: Quote from: beanflying on March 30, 2019, 07:49:47 amYea, the fluke covers 85% of my use cases but that 15% keeps bothering me. Less than half of a Valhalla or Datron unit though. I only even need 200V to mostly calibrate but the gain will be pretty poor beyond that.Quote from: Jay_Diddy_B on March 30, 2019, 07:53:55 amI'm not really worried about being incredibly accurate but I would like to be able to calibrate gain and high frequency response to few hundred volts(Ideally 480V).

author: beanflying
author_rank: Super Contributor
timestamp: March 30, 2019, 08:03:32 am
content: Quote from: Jay_Diddy_B on March 30, 2019, 07:53:55 amProviding you can trick the 5200 into believing it is in the 1000V range there is some more current to play with (200mA). It doesn't actually output the higher voltages hence the Power Amp.

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: March 30, 2019, 08:06:50 am
content: Quote from: beanflying on March 30, 2019, 07:49:47 amI had a look at the 2703 manual. It looks like the 1200V range is restricted to 1kHz max.Regards,Jay_Diddy_B

author: Kleinstein
author_rank: Super Contributor
timestamp: March 30, 2019, 08:10:28 am
content: Normal mains transformers are not that bad at slightly higher frequencies - up to some 500 Hz it's more like getting easier in the low power region.I have used a normal mains-transformer (some 3 VA) just driven from a 50 Ohms function generator to get some 200 V up to 10 kHz. I had no need for a stable amplitude however (just a stable frequency).Output transformers for tube amplifiers could be an option too.

author: maginnovision
author_rank: Super Contributor
timestamp: March 30, 2019, 08:20:45 am
content: https://www.digikey.com/product-detail/en/hammond-manufacturing/714/HM5165-ND/455546I actually have this transformer I bought for... a worse idea than this. So I've got input filters, mil-spec 3mA fast blow fuses and housings, switches with neon indicators, 3kV binding posts, 5kV wire and leads, a steel box. I would probably need to read up more on magnetics to be sure of an idea like this so I thought I'd ask here where someone might already know better than me.

author: beanflying
author_rank: Super Contributor
timestamp: March 30, 2019, 08:35:13 am
content: Quote from: Jay_Diddy_B on March 30, 2019, 08:06:50 amIt is but so far I haven't found it an issue for anything I own. Not sure what it won't be able to calibrate with that limit in the way of DMM's it will do 6 1/2 Digits of Agilent which is what I have mainly in high end meter/loggers.

author: maginnovision
author_rank: Super Contributor
timestamp: March 30, 2019, 08:41:35 am
content: Quote from: Kleinstein on March 30, 2019, 08:10:28 amFor right now I'm specifically interested in 500Hz for low frequency, and3020kHz for high frequency. I can use as little as 200V to calibrate I'd prefer higher though.

author: maginnovision
author_rank: Super Contributor
timestamp: March 30, 2019, 08:42:52 pm
content: I did some testing and found the transformer to put out 300V RMS with 6.74V RMS input @ 12.6kHz(and lots of whining). However taking it all the way to 20kHz gave me an output of about 43V RMS. Just did a Bode plot and it does peak about 12.52kHz, and by 20kHz it's 3dB down even from below 1kHz. So I should be able to get a usable voltage, but I probably need a smaller transformer to get the voltage I want with the current available. Close enough.

author: maginnovision
author_rank: Super Contributor
timestamp: April 03, 2019, 06:01:27 am
content: Another update, in case anyone tries to follow this. I've ordered a couple of custom transformers 0-100V input 0-1000V output, 1 @ 500Hz nom., 1 @ 10-20kHz nom. They're small and have 15kV rated secondaries. Less than 50mA primary draw and about 1uA output current with 5-10C temp rise. Once I get them I'll update on whether or not I destroyed the transformers.