A Audio and hi-fi forum. AudioBanter.com

Go Back   Home » AudioBanter.com forum » rec.audio » Pro Audio
Site Map Home Register Authors List Search Today's Posts Mark Forums Read Web Partners

I Built and Used My First Incandescent Bulb Current-Limiter



 
 
Thread Tools Display Modes
  #21  
Old December 22nd 20, 02:14 AM posted to rec.audio.pro
Ralph Barone[_3_]
external usenet poster
 
Posts: 53
Default I Built and Used My First Incandescent Bulb Current-Limiter

> wrote:
> Scott Dorsey wrote:
>
> ===================
>>>
>>> But I would assume the bulb lighting up initially, is due
>>> to the initial in-rush current, that charges up the electrolytic
>>> filtering caps, on the outputs of the rectifiers?

>>
>> No. This is a "power-on thump" which is caused by the coupling capacitors
>> charging up, not the power supply.
>>

>
> ** The OP never mentioned any " thump" and is not talking about one.
>
>> It's made much worse with amplifiers that run on a single supply rail, so
>> the output of the power amp stage is sitting halfway between the supply
>> rail and ground during normal operation. This means there is a huge
>> coupling capacitor from the output stage to the speaker and that has to
>> charge up. While it is charging up, the woofer coil will bottom out.
>>
>>

> ** Nonsense, speaker output electros ( rarely seen in the last 30
> years) do not do that, they charge slowly.
>
> I = C.dv/dt
>
> if C = 2000uF and the cap charges to 30V in 0.5 second, I = 120mA.
>
> To " bottom out " a woofer a takes several amps.
>


Sure. But let’s say that the power supply comes up to full voltage in 1/4
cycle, which is perhaps closer to the truth. 1/4 cycle is either 4.33 or 5
ms, depending on where you live. Punch in those numbers and you get dV/dt =
30/0.005 = 6000 V/sec and I = 6000 * 0.002 = 12 A. That’ll make your
woofer move.


>> Well-designed amplifiers have a protection relay that cuts the speaker off
>> when there is any appreciable DC offset. It will sometimes take a little
>> time to stabilize because of the turn-on thump.

>
> ** Direct coupled amps sometimes have such relays, a great many do not
> and don't need them.
>
> In most cases, a simple muting FET between the pre and power stage does the job.
>
>
> ......... Phil
>
>




Ads
  #22  
Old December 22nd 20, 02:26 AM posted to rec.audio.pro
[email protected]
external usenet poster
 
Posts: 38
Default I Built and Used My First Incandescent Bulb Current-Limiter

Ralph Barone wrote:
=================
>
> > ** Nonsense, speaker output electros ( rarely seen in the last 30
> > years) do not do that, they charge slowly.
> >
> > I = C.dv/dt
> >
> > if C = 2000uF and the cap charges to 30V in 0.5 second, I = 120mA.
> >
> > To " bottom out " a woofer a takes several amps.
> >

> Sure. But let’s say that the power supply comes up to full voltage in 1/4
> cycle, which is perhaps closer to the truth.


** Irrelevant what the main PSU voltage does- and it is never a short as 5ms.
The mid point voltage of a single supply output stage rise *independantly*.

Like I posted, it typically takes a second or two.

..... Phil



  #23  
Old December 22nd 20, 02:28 AM posted to rec.audio.pro
Paul Dorman
external usenet poster
 
Posts: 55
Default I Built and Used My First Incandescent Bulb Current-Limiter

On 12/21/2020 5:56 PM, wrote:
> Paul wrote:
> ============
>>>
>>> ** The largest part of the " inrush surge " is down to the iron transformer
>>> core *magnetising* and losing nearly all of its inductance at switch own.

>>
>>> Can take 20 cycles of AC power for the core to unmagnetise too.
>>>
>>> SMPSs usually surge hard at a switch on too, yours must be an exception.
>>>

>>
>> The iron transformer is magnetizing every cycle, which
>> would be 60 times a second, for 60Hz AC.
>>

>
> ** But not at *switch on * !!!!!!!!!
>
> The phenomenon is called " inrush surge" and is a *whole subject* on its own.
>
> This article from my colleague Rod Elliott may give you a hint.
>
> https://sound-au.com/articles/inrush.htm
>


From that article:

"Things become far more complicated when the secondary feeds a
rectifier, followed by a large bank of filter capacitors. Worst case
inrush current is still limited by the winding (and other) resistances,
but the capacitor bank appears to be a short circuit at the output of
the transformer. Depending on the size of the capacitors, the apparent
short circuit may last for some time. During this period, the
transformer will be grossly overloaded, but this is of little
consequence. Transformers can withstand huge overloads for a short
period with no damage, and they will normally last (almost) forever even
when subjected to such abuse many times a day."



  #24  
Old December 22nd 20, 02:36 AM posted to rec.audio.pro
[email protected]
external usenet poster
 
Posts: 38
Default I Built and Used My First Incandescent Bulb Current-Limiter

Paul the Pedant wrote:

==================

> >>>
> >>> ** The largest part of the " inrush surge " is down to the iron transformer
> >>> core *magnetising* and losing nearly all of its inductance at switch own.
> >>
> >>> Can take 20 cycles of AC power for the core to unmagnetise too.
> >>>
> >>> SMPSs usually surge hard at a switch on too, yours must be an exception.
> >>>
> >>
> >> The iron transformer is magnetizing every cycle, which
> >> would be 60 times a second, for 60Hz AC.
> >>

> >
> > ** But not at *switch on * !!!!!!!!!
> >
> > The phenomenon is called " inrush surge" and is a *whole subject* on its own.
> >
> > This article from my colleague Rod Elliott may give you a hint.
> >
> > https://sound-au.com/articles/inrush.htm
> >

> From that article:
>
> "Things become far more complicated when the secondary feeds a
> rectifier, followed by a large bank of filter capacitors. Worst case
> inrush current is still limited by the winding (and other) resistances,
> but the capacitor bank appears to be a short circuit at the output of
> the transformer. Depending on the size of the capacitors, the apparent
> short circuit may last for some time. During this period, the
> transformer will be grossly overloaded, but this is of little
> consequence. Transformers can withstand huge overloads for a short
> period with no damage, and they will normally last (almost) forever even
> when subjected to such abuse many times a day."
>


** Please enjoy eating your carefully hand picked cherries.

And don't choke on the pips .....


..... Phil

  #25  
Old December 22nd 20, 04:44 AM posted to rec.audio.pro
[email protected]
external usenet poster
 
Posts: 38
Default I Built and Used My First Incandescent Bulb Current-Limiter

Ralph Barone wrote:
=================
> >

> Section 4 of your linked article talks about transformer inrush, which is a
> definite concern for equipment with large power transformers. We had an
> event a couple years ago when energizing some 500 MVA, 500 kV transformers
> at the wrong point on wave resulted in a large outage and actual
> destruction of some other equipment in the vicinity.
>

** Be like bomb going off.

FYI:
Transformers a *lot smaller* can be a problem also.

1. Any toroidal power transformer of 800VA or more rating will regularly trip a household breaker at switch on.

2. A 1kVA conventioal job will do the same.

3. 40uF of AC rated film capacitors on the same switch will do it too ( for 240VAC power) .

4. Ditto for 2 or more colour CRT screens switched together.

Each of the above cause 150A peak surges that trip the magnetic part of the breaker.


...... Phil
  #26  
Old December 22nd 20, 06:16 AM posted to rec.audio.pro
Paul Dorman
external usenet poster
 
Posts: 55
Default I Built and Used My First Incandescent Bulb Current-Limiter

On 12/21/2020 6:36 PM, wrote:
> Paul the Pedant wrote:
>
> ==================
>
>>>>>
>>>>> ** The largest part of the " inrush surge " is down to the iron transformer
>>>>> core *magnetising* and losing nearly all of its inductance at switch own.
>>>>
>>>>> Can take 20 cycles of AC power for the core to unmagnetise too.
>>>>>
>>>>> SMPSs usually surge hard at a switch on too, yours must be an exception.
>>>>>
>>>>
>>>> The iron transformer is magnetizing every cycle, which
>>>> would be 60 times a second, for 60Hz AC.
>>>>
>>>
>>> ** But not at *switch on * !!!!!!!!!
>>>
>>> The phenomenon is called " inrush surge" and is a *whole subject* on its own.
>>>
>>> This article from my colleague Rod Elliott may give you a hint.
>>>
>>> https://sound-au.com/articles/inrush.htm
>>>

>> From that article:
>>
>> "Things become far more complicated when the secondary feeds a
>> rectifier, followed by a large bank of filter capacitors. Worst case
>> inrush current is still limited by the winding (and other) resistances,
>> but the capacitor bank appears to be a short circuit at the output of
>> the transformer. Depending on the size of the capacitors, the apparent
>> short circuit may last for some time. During this period, the
>> transformer will be grossly overloaded, but this is of little
>> consequence. Transformers can withstand huge overloads for a short
>> period with no damage, and they will normally last (almost) forever even
>> when subjected to such abuse many times a day."
>>

>
> ** Please enjoy eating your carefully hand picked cherries.
>
> And don't choke on the pips .....
>


Well, these cherries support my argument that the initial
1 second of high current is due to the charging of the first
filter caps.

If you have cherries that can disprove my argument,
please present them.

  #27  
Old December 22nd 20, 06:38 AM posted to rec.audio.pro
[email protected]
external usenet poster
 
Posts: 38
Default I Built and Used My First Incandescent Bulb Current-Limiter

Paul wrote:

====================
>
> If you have cherries that can disprove my argument,
> please present them.
>


** Never cherry pic - it is ALWAYS a false argument.

My colleague's cite does not back you up one tiny bit. It is NOT about
the use of a dim bulb but operation at switch on with no limiting

I have already answered your fake idea.

Only tube amps do as you claim, it's due to tube heater current surge.
Tube rectifiers *never* allow filter cap surges.

FOAD.

...... Phil

  #28  
Old December 22nd 20, 07:19 AM posted to rec.audio.pro
Paul Dorman
external usenet poster
 
Posts: 55
Default I Built and Used My First Incandescent Bulb Current-Limiter

On 12/21/2020 10:38 PM, wrote:
> Paul wrote:
>
> ====================
>>
>> If you have cherries that can disprove my argument,
>> please present them.
>>

>
> ** Never cherry pic - it is ALWAYS a false argument.
>
> My colleague's cite does not back you up one tiny bit. It is NOT about
> the use of a dim bulb but operation at switch on with no limiting
>
> I have already answered your fake idea.
>
> Only tube amps do as you claim, it's due to tube heater current surge.
> Tube rectifiers *never* allow filter cap surges.
>
> FOAD.
>
> ..... Phil
>


People resort to profanities when they don't have any real logical
argument!

You didn't even READ the link you posted! It fully supports my
argument! Thanks!


  #29  
Old December 22nd 20, 11:10 AM posted to rec.audio.pro
[email protected]
external usenet poster
 
Posts: 38
Default I Built and Used My First Incandescent Bulb Current-Limiter

Paul the Prick wrote:

===============

> >>
> >> If you have cherries that can disprove my argument,
> >> please present them.
> >>

> >
> > ** Never cherry pic - it is ALWAYS a false argument.
> >
> > My colleague's cite does not back you up one tiny bit. It is NOT about
> > the use of a dim bulb but operation at switch on with no limiting
> >
> > I have already answered your fake idea.
> >
> > Only tube amps do as you claim, it's due to tube heater current surge.
> > Tube rectifiers *never* allow filter cap surges.
> >
> > FOAD.

>
> People resort to profanities when they don't have any real logical
> argument!



** Like hell I don't.

>
> You didn't even READ the link you posted! It fully supports my
> argument! Thanks!


** You rotten bloody LIAR !!! It does nothing of the sort.

FYI:

Mr Elliott is a friend, he lives in Sydney as do I.
That article would never have been written without my urging and my input.
He and I discussed the facts it contains for many hours.

I was way ahead of him, but he then did his own testing and fully agreed.
Look over his site - many articles there are by me.


OTOH - you are nothing but a POS ****** with a very bad attitude.

I do hope you are 13 years old.

Cos otherwise you are comprehensively ****ed for the rest of you life


...... Phil

  #30  
Old December 22nd 20, 04:31 PM posted to rec.audio.pro
Don Pearce[_3_]
external usenet poster
 
Posts: 2,351
Default I Built and Used My First Incandescent Bulb Current-Limiter

On Mon, 21 Dec 2020 03:55:24 -0800 (PST), "
> wrote:

>Don Pearce, Lying, Bull****ting pommy idiot spewed:
>
>===========================================
>
>> >> >Because the initial 1 second flash only happened with a
>> >> >linear power supply guitar amp, and did not happen with
>> >> >my switched-mode guitar amp. With the latter, the bulb
>> >> >never glowed noticeably, even at turn-on.
>> >
>> >------------------------------------------------------------------------------
>> >> You will find that the bulb has a rather finite lifetime.
>> >>
>> >
>> >** ROTFLMAO - how ****ing ABSURD !!
>> >

>
>** Suspect Don has realised his stupid blunder here.
> Bit will never admit to it.
> --------------------------------------------------------------------
>
>
>> >> a negative temperature coefficient
>> >> (NTC) thermistor. Any switched mode power supply is most likely to
>> >> already have one fitted, which is why your bulb seems to do nothing.
>> >>
>> >** Wot utter GARBAGE !!!!
>> >
>> >Don the Nong has less that ZERO idea of what he is speaking about.
>> >

> -----------------------------------------------------------------------
>>
>> >

>> You are insulting a man who has designed switched mode power supplies,

>
>** But clearly, not insulted him near enough to shut the idiot up.
>
>
>> and has included NTC thermistors for the purpose of limiting switch-on
>> inrush current.

>
>** The geriatric fool has no clue at all.
>

Shame you didn't read your mate's article - which you claim to have
contributed to (an obvious lie). If you had you would have seen the
chapter about the use of NTC thermistors in limiting PSU inrush
current, and describing them as well-established. I presume according
to you he is also a geriatric fool with no clue.

Please take the meds, Phil.

d
 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
trap their bulb in addition the pot Karl I. Slanina, MPSE Car Audio 0 November 8th 07 08:13 PM
Marantz 110 Tuner - Bulb Replacement Neil Tech 1 April 1st 07 04:42 AM
Hickok 752 #81 "fuse bulb" question The Great Randi of Audio Vacuum Tubes 1 July 4th 05 04:09 PM
FA/FS Federal AM- 864/U Tube Compressor Limiter MANUAL Benchmark-IFA-2 Roland SRV2000/CBS411 limiter..... Port Pro Audio 0 August 28th 04 06:17 PM
*FROGGY THE DIM-BULB FRENCH BOY* Le Lionellaise Audio Opinions 0 September 19th 03 03:35 PM


All times are GMT +1. The time now is 06:24 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.
Copyright 2004-2021 AudioBanter.com.
The comments are property of their posters.