PSU designer understanding.
- pre65
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#46 Re: PSU designer understanding.
On some Hammond data sheets they give a max working voltage and a hi-pot test voltage which is significantly higher.
On my choke (193Q) they only list the max working voltage of 1000V. I dare say it is safe to use above that voltage but I don't know the margin.
Finding a 10H choke safe for 1400V is proving difficult and could be expensive.
Perhaps I should stay at 1000v, and get the red spot by driving the grid harder ?
On my choke (193Q) they only list the max working voltage of 1000V. I dare say it is safe to use above that voltage but I don't know the margin.
Finding a 10H choke safe for 1400V is proving difficult and could be expensive.
Perhaps I should stay at 1000v, and get the red spot by driving the grid harder ?
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
#47 Re: PSU designer understanding.
Well, by definition it isn't. Nobody makes something safe to 1500v and thinks, lets just sell it as safe for 1000v.I dare say it is safe to use above that voltage
There is a reason for that.Finding a 10H choke safe for 1400V is proving difficult and could be expensive.
A copy of photoshop would be simpler. Remember less voltage means more current to get the same power.Perhaps I should stay at 1000v, and get the red spot by driving the grid harder ?
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#48 Re: PSU designer understanding.
I’d go anyway on 1000v these days. I think me and Nick wound the GM70 past it’s max on Collin’s electrostatics which sounded flat. As GM70’s were plentiful and chepa those days, didn’t matter I had double figures GM70’s .... still do at the lockup.
No, these days, we don’t need to go past 1000 volts, especially now were more clued up on providing double figure grid currents; since to my ears such valves open out better when you incorporate the positive characteristic curves.
No, these days, we don’t need to go past 1000 volts, especially now were more clued up on providing double figure grid currents; since to my ears such valves open out better when you incorporate the positive characteristic curves.
Last edited by Paul Barker on Wed Apr 29, 2020 9:30 pm, edited 1 time in total.
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
- pre65
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#49 Re: PSU designer understanding.
Yes, but it does not stop being safe at 1001v, or 1010v, so there would normally be some leeway.
Anyway, the question does not arise now.
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
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- Paul Barker
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#50 Re: PSU designer understanding.
Well in th gas world when you gas rate an appliance you allow a tolerance of 5% over 10% under, which would in our world be a very safe standard.
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
#51 Re: PSU designer understanding.
But you don't know, that’s the point.Yes, but it does not stop being safe at 1001v, or 1010v, so there would normally be some leeway.
Also, I bet your meter is not calibrated against a known standard, so you may be running 5% higher than you think you are. Add the fact your mains may increase by 5% without you noticing, that's you at 1100v.
But its your call. You do ask for advice, its up to you if you chose to pay attention to it.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
- pre65
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#52 Re: PSU designer understanding.
I am accepting unequivocally the advice I have been given. Thanks again for giving it.Nick wrote: ↑Wed Apr 29, 2020 10:55 pmBut you don't know, that’s the point.Yes, but it does not stop being safe at 1001v, or 1010v, so there would normally be some leeway.
Also, I bet your meter is not calibrated against a known standard, so you may be running 5% higher than you think you are. Add the fact your mains may increase by 5% without you noticing, that's you at 1100v.
But its your call. You do ask for advice, its up to you if you chose to pay attention to it.
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
- izzy wizzy
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#53 Re: PSU designer understanding.
I've got a 10h 500ma choke suitable for choke input off 2.1kv ct tx. I don't know it's insulation rating but can find out. If you need one? It's Majestic. But unless you need choke input, it's huge and of course very heavy.
#54 Re: PSU designer understanding.
I am really rusty but can you run the choke in the return line. Does that help at all?
- pre65
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#55 Re: PSU designer understanding.
One of us had a batch of 10H chokes custom made up north (further north than Yorkshire) quite a few years ago, might have been Will.izzy wizzy wrote: ↑Thu Apr 30, 2020 8:07 am I've got a 10h 500ma choke suitable for choke input off 2.1kv ct tx. I don't know it's insulation rating but can find out. If you need one? It's Majestic. But unless you need choke input, it's huge and of course very heavy.
They are substantial, but I've no idea of the voltage or current rating. Can anyone else who got one (or two) remember ?
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
#56 Re: PSU designer understanding.
Yes, it helps the windings to core requirement at least.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
- pre65
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#57 Re: PSU designer understanding.
Yes it was Will, I found the thread. 10H @ 250ma and 95R DCR. My two were the ones Colin ordered.pre65 wrote: ↑Thu Apr 30, 2020 10:07 amOne of us had a batch of 10H chokes custom made up north (further north than Yorkshire) quite a few years ago, might have been Will.izzy wizzy wrote: ↑Thu Apr 30, 2020 8:07 am I've got a 10h 500ma choke suitable for choke input off 2.1kv ct tx. I don't know it's insulation rating but can find out. If you need one? It's Majestic. But unless you need choke input, it's huge and of course very heavy.
They are substantial, but I've no idea of the voltage or current rating. Can anyone else who got one (or two) remember ?
http://www.audio-talk.co.uk/phpBB3/view ... oke#p27015
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
- pre65
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#58 Re: PSU designer understanding.
More playing with PSU designer.
Using the 800V transformer and a first cap of 10uf (2 X 5uf) I'm getting a nice 1000v HT
The first caps are MKP low inductance 5uf. Un = 1200v, Umax = 1680v ESR = 1.1Mw (?) Irms = 64A
Using the 800V transformer and a first cap of 10uf (2 X 5uf) I'm getting a nice 1000v HT
The first caps are MKP low inductance 5uf. Un = 1200v, Umax = 1680v ESR = 1.1Mw (?) Irms = 64A
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
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#59 Re: PSU designer understanding.
It seems a good compromise.
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#60 Re: PSU designer understanding.
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."