Maker Pro
Maker Pro

Generators and switch mode power supplies.

S

Sylvia Else

Jan 1, 1970
0
JosephKK said:
May not have happened yet down there, but has been around for about 2
decades in the US now.

Given that PC power supplies are essentially a world-wide commodity
item, I'd have thought that Australia would have inherited any
improvements mandated in other jurisdictions, even if there were no
local regulations.

But I knocked together a current-transformer, and looked at the current
drawn by three PCs and a monitor, (being the input current to a
switch-over type UPS when it's not operating in backup mode). What I see
seems to be what an un-harmonic-corrected power supply would draw.

Sylvia.
 
S

Sylvia Else

Jan 1, 1970
0
Phil said:
"Stupider than Anyone Else Alive "



** TOTAL BOLLOCKS !!!




** Wrong spec - IMBECILE !




** Pedantic TWADDLE.

Meaning you didn't understand it.
Diode forward voltage ( Vf) is not a fixed number - it is a function of
both current and chip temperature.

Didn't I say that it varied? Oh yes, I did. But you snipped that because
had you not done so, you comment would have looked as silly as it
actually is.
Diode dissipation is the product of Vf & If at any instant.

Yes. Your point being?

Sylvia.
 
P

Phil Allison

Jan 1, 1970
0
" Stupider than Anyone Else Alive "


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Meaning you didn't understand it.


** Meaning it ** IS ** PEDANTIC TWADDLE !!

Yes. Your point being?


** Proves your assertion above re " not current waveform " 100% WRONG

Obvious to anyone but a

DEMENTED TROLLING PSYCHOPATH

**** OFF !!!



....... Phil
 
S

Sylvia Else

Jan 1, 1970
0
Phil said:
" Stupider than Anyone Else Alive "





** Meaning it ** IS ** PEDANTIC TWADDLE !!




** Proves your assertion above re " not current waveform " 100% WRONG

I said "mainly", which I stand by. Increasing the current with a
proportionate decrease in the time it flows produces only a modest
increase in average power dissipation, because the forward voltage
increases only slowly (with a logarithmic character) with current.

Sylvia.
 
P

Phil Allison

Jan 1, 1970
0
" Much Stupider than Anyone Else Alive "


------------------------------------------------------------------


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Meaning you didn't understand it.


** Meaning it ** IS ** PEDANTIC TWADDLE !!

Yes. Your point being?


** Proves your assertion above re " not current waveform " 100% WRONG

Obvious to anyone but a

DEMENTED TROLLING PSYCHOPATH

**** OFF !!!



....... Phil
 
N

Nobody

Jan 1, 1970
0
Where all the competing products were previously externalising the cost,
and all now have to internalise it, the cost must inevitably be passed
on to the consumer, because there's no change in competition.

That assumes that competing products are similarly affected, which isn't
always the case.
 
A computer PSU ( without PF correction) might like a modified sine
better than a real sine.

What is the conduction angle of the bridge rectifiers on a simple PSU
when operated on a modified sine as compared to a real sine wave? It
is possible that the RMS current is LOWER on the modified sine because
the rectifers can conduct for the full time of the flat top of the
square wave. In the case of the sine, they conduct for only a breif
pulse at the tip of the sine.

I don't think the answer is as simple as some of you are saying..

Mark
 
R

Richard The Dreaded Libertarian

Jan 1, 1970
0
PFC prevents fires, too. You approve of fires?

In their right place, they're fine. What I disapprove of is arbitrary
legislation to force people to buy stuff they don't want.

Hope This Helps!
Rich
 
Given that PC power supplies are essentially a world-wide commodity
item, I'd have thought that Australia would have inherited any
improvements mandated in other jurisdictions, even if there were no
local regulations.

A power supply can be designed with harmonic correction. Then that
same circuit may be 'forgotten' when the same supply is sold in
Australia. Harmonic suppression is required in Europe. A same supply
without that harmonic compensation is sold elsewhere with a slightly
different model number.

A power supply manufacturer may not need to meet local
requirements. A computer that must suppress harmonics is the
responsibility of the computer assembler - not of the power supply
manufacturer. Therefore many power supply manufacturers dump into the
market products that violate local standards. He is not responsible.
The computer assembler who buys his supplies may be responsible for
meeting those code requirements. Unfortunately many computer
assemblers have so little technical knowledge as to not even know what
harmonics are.

I have no idea what that market discussion has to do with
harmonics. I believe the original question was about a computer
operating on a generator. Computer power supplies must be so robust
as to make those square waves (modified sine waves) irrelevant. But
again, did a power supply manufacturer bother to meet industry
standards? Or simply forget some components to sell a cheaper supply
also for higher profits?
 
P

Phil Allison

Jan 1, 1970
0
A computer PSU ( without PF correction) might like a modified sine
better than a real sine.

** BULL !!!
What is the conduction angle of the bridge rectifiers on a simple PSU
when operated on a modified sine as compared to a real sine wave?


** Much shorter.

It
is possible that the RMS current is LOWER on the modified sine because
the rectifers can conduct for the full time of the flat top of the
square wave.

** No it is not possible.

In the case of the sine, they conduct for only a breif
pulse at the tip of the sine.

** WRONG.

There is a half sine shaped current pulse that lasts 2 to 3 mS.

I don't think the answer is as simple as some of you are saying..


** The only simple thing around here is YOU - pal.



...... Phil
 
S

Sylvia Else

Jan 1, 1970
0
Phil said:
** BULL !!!



** Much shorter.

Seems to me it's longer. As Mark has observed, it will conduct for as
long as the modified sine wave remains high - though pulsed as the
switcher turns on and off.

That said, the current will consist of an initial high pulse to recharge
the capacitor, followed by low pulses that average to the short term PSU
output.
** No it is not possible.

The RMS current thing is a red herring anyway. While it's well enough
defined, it has significance only for current passing through a circuit
element that behaves like a resistor, which a rectifier doesn't.
** WRONG.

There is a half sine shaped current pulse that lasts 2 to 3 mS.

Depends on your definition of brief, Phil.
** The only simple thing around here is YOU - pal.

So you do not consider me to be simple.

Sylvia.
 
S

Sylvia Else

Jan 1, 1970
0
Richard said:
In their right place, they're fine. What I disapprove of is arbitrary
legislation to force people to buy stuff they don't want.

The alternative is for the electricity supplier to impose contractual
conditions requiring that the customer not impose singificant harmonic
loads. If the customer fails to comply then they could be disconnected.

The customer, of course, wouldn't have a clue about this, and violations
would be frequent.

Must simpler if the customer can't buy non-compliant gear in the first
place.

Sylvia.
 
P

Phil Allison

Jan 1, 1970
0
"Stupider than Anyone ELSE
Seems to me it's longer. As Mark has observed, it will conduct for as long
as the modified sine wave remains high - though pulsed as the switcher
turns on and off.


** The initial current surge will be much greater and shorter than with a
sine wave - so its rms value will be much higher.

The duration of the "high" condition will be short, if the UPS is lightly
loaded.

The RMS current thing is a red herring anyway.


** ABSOLUTE BOLLOCKS !!

While it's well enough defined, it has significance only for current
passing through a circuit element that behaves like a resistor, which a
rectifier doesn't.


** The rms current value is *directly applicable* to any series resistors,
NTC thermistors, filter inductors and filter electros.


Depends on your definition of brief,


** Conduction over 60 degrees of angle extends way beyond the " tip of the
sine".

So you do not consider me to be simple.


** ROTFL !!

YOU Sylvia, are totally FUCKED in the HEAD !!



...... Phil
 
S

Sylvia Else

Jan 1, 1970
0
Phil said:
"Stupider than Anyone ELSE



** The initial current surge will be much greater and shorter than with a
sine wave - so its rms value will be much higher.

The duration of the "high" condition will be short, if the UPS is lightly
loaded.

The length of the high condition is not a function of load, AFIA. The
idea of a modified sine wave is to maximise the amplitude of the
fundamental versus the harmonics, within the contraints of a simple
switching circuit.
** ABSOLUTE BOLLOCKS !!

As usual, a cogent argument from Phil.
** The rms current value is *directly applicable* to any series resistors,
NTC thermistors, filter inductors and filter electros.

We're talking about the rectifiers, Phil.
** Conduction over 60 degrees of angle extends way beyond the " tip of the
sine".
So?


** ROTFL !!

YOU Sylvia, are totally FUCKED in the HEAD !!

It's logic, Phil. If Mark's the only simple thing around here (I offer
no view), then either I'm not around here, or I'm not a simple thing.

Do you want to argue that I'm not around here?

Sylvia.
 
P

Phil Allison

Jan 1, 1970
0
"Stupider than Anyone ELSE
The length of the high condition is not a function of load, AFIA.


** Fraid it is.

That is how the devices regulate their output voltage to 230 volts rms.


The idea of a modified sine wave is to maximise the amplitude of the
fundamental versus the harmonics, within the contraints of a simple
switching circuit.

** 100% BULL !!


We're talking about the rectifiers, Phil.


** No such restriction exists.

Here is the (sub) topic:

" A computer PSU ( without PF correction) might like a modified sine
better than a real sine. "


It's logic, Phil. If Mark's the only simple thing around here (I offer no
view), then either I'm not around here, or I'm not a simple thing.


** YOU Sylvia, are totally FUCKED in the HEAD !!

Soooo much worse then merely " simple".



...... Phil
 
J

JosephKK

Jan 1, 1970
0
Almost right.

To externalise costs, you have to push them onto the general public.
Pushing costs only onto your customers puts you at a competitive
disadvantage.

Yes, pushing the costs to the public is much more effective. Pollution
and environmental degradation are classic forms of this.
If legislation pushes a cost onto the manufacturer, it becomes a
manufacturing cost, no different to the cost of raw materials or labour.
Whether it gets pushed onto the customer or eats into the manufacturer's
profit margin depends upon the degree of competition.

Also correct.
 
J

JosephKK

Jan 1, 1970
0
That assumes that competing products are similarly affected, which isn't
always the case.

Agreed. Producers in Europe and USA have the highest costs, sloping
downward to elsewhere including South American nations, China, India
and finally African nations. These have varying amounts of
environmental laws, labor laws (which impacts labor costs), and other
taxes and benefits. It is quickly clear why so much off-shoring goes
to China and India and a lesser amount to other places.
 
J

JosephKK

Jan 1, 1970
0
In their right place, they're fine. What I disapprove of is arbitrary
legislation to force people to buy stuff they don't want.

Hope This Helps!
Rich

But there are people who want it (the utilities). Moreover since it
tends to minimize electric distribution infrastructure costs it can be
related to something residential customers can understand, their
electric rates. Trade-offs like this is part of what makes regulation
complex (some find thinking on these things fun, they are called
policy wonks).
 
S

Sylvia Else

Jan 1, 1970
0
JosephKK said:
But there are people who want it (the utilities). Moreover since it
tends to minimize electric distribution infrastructure costs it can be
related to something residential customers can understand, their
electric rates. Trade-offs like this is part of what makes regulation
complex (some find thinking on these things fun, they are called
policy wonks).

It's an equity issue. Why should consumers who don't use high power SMPS
(mainly in computers) subsidise those who do?

Sylvia.
 
S

Sylvia Else

Jan 1, 1970
0
Phil said:
"Stupider than Anyone ELSE



** Fraid it is.

When unloaded, my UPS produces pulses that are of the same length as
when it's loaded, but there is a significant downward slope to top of
the positive going pulses, and upward slope to the bottom of the
negative going pulses.

Sylvia.
 
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