Clearly this one was over the hills and far away.
I don't mind ... it's always good to try to push past the limits, because it is in that way that we find ourselves setting new limits.
Thanks again, for your time :smile:
Thanks for the reply pbuk :smile:
Apologies for certain omissions ... and thank you for your median equation.
I simply totalled the population groups and divided by 2 (mimicking the method that is often quoted).
The Data Set
The data set population is * 1000, to match the 'State Count'...
Hello everyone :)
I'm struggling to wrap my head around recalculating a data set based upon median.
The data set represents a fixed distribution pattern of population to income group.
There is no data available for 'population to income group' at differing medians, hence we accept the...
Following up on your request for a list of published studies, I have put together a short list.
I've pulled key statements from each, to provide a rapid overview to go with the titles.
The first four involve oral administration, and therefore directly pertinent to the question.
Yes; but the buffering is not inherently stable - probably from the age of 50 onwards (or whenever it becomes unstable).
Bicarbonate is produced by the kidneys as a buffer against excess acidity in the blood, and is capable of performing this task until the kidneys decline in function (and then...
Here's one that might be worth a read.
There are a number, but I've closed everything down ... time for zzzzz.
I didn't spend any time studying the details.
Primarily, I was looking for general published support for the assertion.
... it was...
I fell upon an article outlining the general health benefits of a balanced pH, and specific anti cancer benefits.
... both concepts are well supported in published studies.
The article then went on to describe a protocol, whereby sodium bicarbonate is dissolved in liquefied honey.
Not this time :biggrin:
I do provide general engineering knowledge - particularly specific tips for universal application.
Here's one I put up two days ago that I did live.
Putting it all on the line helps students believe in themselves :wink:
So as you can see, the project is a small...
I do agree.
The knowledge at our fingertips is... enabling.
I struggle for words to describe this dramatic change that we have witnessed
I make sure that I contribute... the engine rebuild is also being shared.
It's an offshoot from the turntable thread.
I was tidying up all the mess (trying to move on) :biggrin:
... and I found this dual coil, with only two cables.
I thought, before putting it away, I'll find out what it does.
After some feedback, I figured it was safe to test on the window winder motor.
It is very possible that a windscreen wiper motor would be better.
Of course, I am very happy with our project as it is... the difficulty is deciding when to stop learning.
For the brain, it's no longer a question of the specific 'here & now'.
... it's more like "oh... so below a certain...
I may be confused, but... https://en.wikipedia.org/wiki/Electrical_ballast
indicates that this is the purpose of electrical ballast.
I noted a crossover between choke and ballast - choke ballast.
This may be correct or incorrect.
Perhaps if we knew why, what was happening to the current, as it...
I just tried it in series with a motor.
The PSU puts out 19v DC no load.
With the motor running, it drops to 7v.
It can be dropped down to 4v and still run.
With the coil in series - still 19v no load.
With the motor ON the voltage drops to 4v but no sign of life from the motor.
Yes... specifically blue & red - reading 2.3 Ω
This is what confused me.
Only two connectors (each end of the windings).
Almost no resistance.
Yet cabled blue and red (traditionally +ve -ve).
I looked up choke, but so far, enlightenment has not arrived.
...Ah... but electronic ballast...
What's the purpose of this dual coil?
It has a blue and red cable.
It stood alone, mounted (isolated) on the chassis of a PC PSU.
It's in good condition, so I'm keeping it, but what can be achieved with it?
Here's one that will fit... found in the PC PSU.
The alloy is 5mm thick, 70 x 70.
Re the heat paste.
I found it amazing that 30 year old paste around a stereo chip was still a paste under the skin.
However, I'm glad to know that silicone grease works, as I have plenty of that.
The Lamp Modification
This went well.
There is another gain in motor operation.
I ran the motor down to 7 rpm - I think that is the lowest yet seen.
The difference is marginal, but worthy
More Motor Knowledge
Here's the pre-amble explaining how the knowledge was acquired:
The lamp shines...
Actually... it is hours.
I hadn't timed it... but it was switched off for hours.
I looked down and thought hmmm that LED is still glowing.
I flipped the switch to ON... the LED brightened and died.
Development Pause - thoughts and observations
With the product apparently developed - a pause...
A warning about the CGS HA50
It gets hot... enough to cause a blister.
So it definitely needs a safety guard.
Also, the suggested lamp mod!
It will be a good indicator that the system is powered.
You run some tests, write it up, do something else.
The motor isn't turning... so it is very...
Not boring at all.
Moreover, very pertinent to the discussion.
RE the LED across the capacitor.
With the supply cut to the charger... the LED remains illuminated for a long time - 15 minutes at least.
I'm guessing that this is due to the presence of two 680 uf capacitors.
To drain the...
Here it is with an LED added and the diagram updated.
The LED glows while the motor is drawing current, and is just slightly illuminated when live.
... but what's also interesting (and put a smile on my face) :biggrin:
The LED varies the glow according to how hard the motor is working.
That's the info I was looking for... how it should be wired.
I've drafted the wiring diagram as it currently stands, and added a bridge to the polarity switches.
This was also the info I was looking for.
It explains everything to me.
I now understand why one side of the bridge rectifier was...
That's fantastic information Jim.
I really appreciate the sharing of that knowledge.
I will never again disconnect the battery before switching off the battery charger.
For the motor control, we now have two capacitors - one in the charger, the other across the RBV DC output.
As it is currently...
Yes... if only the search for truth was not a dangerous area of interest.
However, confusion does have additional benefits, as it stimulates discovery in areas that otherwise might have been missed.
I gained knowledge of my DMM, which is very useful for future metering.
... but the error threw...
No... it's digital.
Sadly, also no!.
I've just measured the charger output on Lo (with capacitor as per drawing) = 39V AC - 17.8V DC
It remains stable within 0.2V for a minute.
On Hi the output is 44.5V AC - 20.3V DC
Note... It's Sunday evening:
Mains supply is fluctuating between 230V -...
Absaar 108 NE/D2 12V Battery Charger
With added capacitor for motor load
The image seems to have been re-scaled.
Even opening in a new tab fails to show the image at full size.
The only unreadable element is the capacitor spec:
SAMXON 680 µF 200v LP (M) 85 deg
It's the universal difficulty in documenting change.
... the current status as compared to previous status (and maybe in the same post, a mention of the planned mods).
Of course, the writer knows what's happening, but as for everybody else...
RBV 602 bridge rectifier...
Ah... so we are not completely in the dark :smile:
Wrapping up what we have achieved
Motor control panel
As you can see... I fitted the resistor onto it's heat dissipating aluminium bracket
... and then fitted the bracket to it's natural place, only...
The plug flex would tend to lay on the...
I have changed the wiring of the internal capacitor.
It is now wired across the output -ve and the +ve entry to the fuse, similar to Jim's recent suggestion above.
I then wired in the 2nd capacitor after the RBV.
The motor was slowed to 6.5 rpm.
I then disconnected the 2nd...
Well... I wired it as per your photo:
"Trial and error is the approach for this one. See if a 40 watt 12 V lamp on secondary behave noticeably different from a 40watt 240 volt lamp on primary ?
To avoid rectifier drop he could connect it here"
It shows 12V AC with dimmer feed... so it is in...
No... it was a failure.
(Damn... I spent an age creating the wiring art) :biggrin:
The moment that I switched the motor on... I knew.
The first thing was that it wouldn't start - it needed more power.
... then the sound.
I had another capacitor, so I quickly placed it after the...
But to be fair, it was alarm & confusion that was the driver.
Seeing AC everywhere on my meter.
I needed this confirming, not only for this project, but for future metering.
It seems that you are right - my AC meter shows just over double the DC value, even after passing through the...
I fitted the RBV 602 to the output - the two centre pins.
The two outer pins (marked + - ) delivered similar readings... AC just more than double the DC.
I presume that this confirms that something is amiss with my meter.
Anyway, having got the rectifier... I'll see how it works with the motor.
I've metered it again, on both fast and normal charge (without capacitor across output).
in both cases AC is showing slightly more than double the DC.
Re the capacitor.
I've found a couple of 50V 0.1 µF capacitors.
I also came across an RBV 602 bridge rectifier...
I was merely reading the meter @ AC & DC settings.
... but let's see what happens with your tests.
All readings below taken on
fast charge setting
DC output = 13.5 V
AC output = 29.1 V
capacitor connected across output
DC output = 20.6 V
AC output = 44.8 V...
... or is it?
Tidying The Loose Ends
The 2 speed motor
We never discovered how the motor reduced speed when it's polarity changed.
Jim put it down to mechanical or electrical wizardry :smile:
That's a perfect holding position for the moment.
The spare motor/drive will be opened in the near...
Yes... that halogen lamp is even smaller, and would sit rigid between solid cores :)
Alternative to the lamp concept
CGS HSA50 1.8k Ω resistor
Typically used as demister heating elements in camera housings, beneath the glass face of the housing.
I do believe that somewhere I have a spare...
Final test of this session
Confirm the need for the dimmed mains supply 'solution'.
With the capacitor wired in parallel with the DC output & the 40 watt lamp in parallel with the dimmed mains supply ...
... the motor was slowed to absolute minimum, yet could be stopped and started.
SAMXON 680 µF 200v LP (M) 85 deg (has polarity)
This was a major success vis a vis visible effect.
Test Method - Lamp & Capacitor
With 40 watt lamp across the primary
The motor was slowed to the absolute minimum.
If stopped... the motor could just restart.
The capacitor was placed across the...
Notes on the popped capacitor
LTEC LZG 105 deg PET 8628D
It had seen use in a PC PSU.
The top was flat when tried.
I'm wondering if I could have damaged it during soldering.
I'll look for an alternative.
Further thoughts... and note that the capacitor failed in the edit above.
Transformer Sound Clarification
With the ear on the transformer chassis:
When powered by standard mains supply
The transformer hums.
In addition: there is also an inconsistent minor ticking
When powered by dimmed mains...
Okay, the 5A is implemented :smile:
Found a 330 µF 25v capacitor on the PC PSU board.
It was difficult to desolder.
The solder cooled instantly before the solder pump could work :frown:
... but got it out.
330 µF 25v capacitor across DC output
This had a similar noise reduction effect to the...
Pauses in development are useful.
They are usually caused by external forces, but in fact they are anyway required.
I must clear up something else tomorrow, and then I'll get back on this.
I'll implement the fuse as suggested, and then look again at resistive loads.
I have the typical 240V...
Yes... development engineering is most definitely fun.
Fine to take a drawing and bring it to life... that hits a different pleasure receptor.
... but creating something, and solving the problems that are encountered, is simply unbeatable.
The final stages are upon us.
Two lamps in the battery charger enclosure would indicate that it was on!
However, I am interested to understand the difference between a lamp filament, and a resistor.
IE. is the resistor idea wrong?
The reason being that I don't have a small 240V lamp.
Neither do I have the resistors...
Just reading up on resistors:
It seems that I would need one rated at 400v.
Current I = V/R 240/1000 = 0.24 Amps
Power consumed P = I2R = 0.242 x 1000 = 57.6 W
10K Ω would consume 5.76 Watts.
100k Ω would consume 0.576 Watts
Is this correct?
I wonder if the resistance could be even...
Yes, TBH I was thinking about a resistor bridging the dimmed output (resistive load).
100W or 40W lamp seemed to make no difference.
Perhaps if the wattage reduced significantly... I think that I have an 8W lamp - or used to have, as it hasn't turned up (and I've been looking).
Or perhaps it...
Wiring a 40W lamp in parallel to the Transformer feed
Haha... thanks Tom... it worked!
The buzzing dropped substantially - barely perceptible (as you'll see in the video below)
You've just jumped the development process... thanks for contributing :smile:
Metering the DC voltage
Measuring the Dimmed live feed
... at DC setting 200V
The reading is up and down, varying from a peak of 1.3V DC to 0.1V DC.
This is a repeating cycle, that hovers mid range then goes up... and then down.
... but max is always momentarily 1.3V DC.
Therefore well under the 2V DC that you warned...