home improvement turns into science fair projects?

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terkio
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Re: home improvement turns into science fair projects?

Post by terkio » Sat Jun 20, 2020 7:45 am

The reactance of a 22uF at 60 Hz is 120 Ohm.
So when plugged on 120V mains the current through the cap is 1A.
I would not dare to do that without protection heavy goggles and gloves despite it should not blow up.
Theory tells, it undergoes a 1A rms current, charges and discharges 60 times per second at 120V dc and - 120V dc.
It doesn't heat because voltage and current are in quadrature ( not exactly because of delta ).
During a 60 Hz cycle, it receives energy, then gives it back, so the net received energy is zero.
Of course, this is well known but boggles my mind thinking about such a large ripple current that would quickly ruin power supply caps.

Plugging a 22uF 400V AC cap on a 240V mains socket looks scary to me. Instinctively I do not trust theory, I do not feel, it is safe to do that.

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JR.
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Re: home improvement turns into science fair projects?

Post by JR. » Sat Jun 20, 2020 8:34 am

terkio wrote:
Sat Jun 20, 2020 7:45 am
The reactance of a 22uF at 60 Hz is 120 Ohm.
Don't forget that the cap is also in series with the blower.
So when plugged on 120V mains the current through the cap is 1A.
I would not dare to do that without protection heavy goggles and gloves despite it should not blow up.
Theory tells, it undergoes a 1A rms current, charges and discharges 60 times per second at 120V dc and - 120V dc.
It doesn't heat because voltage and current are in quadrature ( not exactly because of delta ).
During a 60 Hz cycle, it receives energy, then gives it back, so the net received energy is zero.
Of course, this is well known but boggles my mind thinking about such a large ripple current that would quickly ruin power supply caps.
The cap does not charge and discharge every cycle, but passes the current through without much (any?) terminal voltage across it.
Plugging a 22uF 400V AC cap on a 240V mains socket looks scary to me. Instinctively I do not trust theory, I do not feel, it is safe to do that.
So don't do that.... I recall over 50 years ago as a junior technician at MIT Instrumentation Lab, some other technicians there dared me to plug a small electrolytic cap into an outlet... Of course it blew up sounding like a rifle shot. :oops: Something you only do once. Coincidentally on that same job, working on an DC to DC switching PS for a navy project we blew up a big film capacitor that was damping switching spikes across a transformer. I was away from bench when that guy blew up and my bench was covered with a blanket of tiny pieces of film (looked a little like snow). :lol:

JR

PS: FWIW I've been using these film caps to scrub off blower speed for probably a year or more already.
Don't only half-ass tune your drums. Visit https://circularscience.com to hear what properly "cleared" drums sound like.

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mediatechnology
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Re: home improvement turns into science fair projects?

Post by mediatechnology » Sun Jun 21, 2020 5:54 am

I did the same thing for one of my PCs case fans - ran the 12V fan on 5V.
https://ka-electronics.com

"States Ordered To Fraudulently Inflate COVID-19 Cases 15 Times Actual Rate"
https://banned.video/watch?id=5efab695672706002f367a0a
"Plandemic/Doctors In Black" https://proaudiodesignforum.com/content/Plandemic.mp4

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JR.
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Re: home improvement turns into science fair projects?

Post by JR. » Sun Jul 26, 2020 11:31 am

JR. wrote:
Fri May 08, 2020 8:52 am
Finally got my smaller diameter (lighter weight) 3/8" hose.

IMG_20200507_135104450.jpg

I wish I had this sorted earlier in the year... but its all good.

I can now spray closer to the tops of my pecan trees.

JR
Image

I just ordered a parade flag pole harness (belt?) that should make it easier to support the weight of this pole.
Image
When fully loaded with spry bottle and hoses full of water, not easy to manage and steer. This harness should make it easier.
===
BTW I am seeing new pecans forming already on my most productive tree...nuts on my other trees are smaller but still coming. I am optimistic that all my spraying this season did something useful. The caterpillar (bacteria) spray pretty much nuked the tent caterpillars this year. 8-)

JR
Don't only half-ass tune your drums. Visit https://circularscience.com to hear what properly "cleared" drums sound like.

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mediatechnology
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Re: home improvement turns into science fair projects?

Post by mediatechnology » Sun Jul 26, 2020 12:17 pm

Hopefully you'll get some nice pecans.
I was in a restaurant in Dennison Texas yesterday and they had 2 lb bags of whole shelled pecan halves for $12/lb.
We already had a bunch in the freezer or I would have gotten some.

I anticipate your battle with squirrels is going to heat up as fall approaches.
https://ka-electronics.com

"States Ordered To Fraudulently Inflate COVID-19 Cases 15 Times Actual Rate"
https://banned.video/watch?id=5efab695672706002f367a0a
"Plandemic/Doctors In Black" https://proaudiodesignforum.com/content/Plandemic.mp4

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JR.
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Re: home improvement turns into science fair projects?

Post by JR. » Sun Aug 02, 2020 10:22 am

I have officially abandoned my franken slave mower (dragging a 22" mower along side the zero turn). The rear attachment angle iron apparently hit a tree and got twisted up. I didn't notice until after I finished the yard.

My new ditch strategy is attach ropes to my DR trimmer and let gravity pull it down the steep sides of the ditch, then use the ropes to pull it back up.
ditchbitch.jpg
Two ropes attached low, and a third strap up high to steer the trimmer. When running, the cutting head pulls the front of the trimmer to the left.
ditch.jpg
I knocked off the front ditch in about an hour... an improvement over negotiating the steep sides of the ditch on foot (that really tears up my bad knee).

Before the state highway crew trenched out my rain ditch deeper several years ago, I could mow the sides of the ditch with my old riding mower... riding up and down the less steep sides of the ditch. Now I wish I bought a tractor with bush hog attachment instead of the zero turn mower... but I do not need even more yard equipment.

JR
Don't only half-ass tune your drums. Visit https://circularscience.com to hear what properly "cleared" drums sound like.

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mediatechnology
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Re: home improvement turns into science fair projects?

Post by mediatechnology » Sun Aug 02, 2020 10:48 am

Seeing the 45 MPH sign makes me wish I were in a small town like Hickory.

Dallas has begun to suck really, really bad.
There is mass mental illness here in the form of TDS and covid-hysteria.
The speed limit on our wooded country-like street is only 25 MPH but 1 mile in either direction and its Mad Max territory.
Like Detroit, Baltimore and Chicago it will never improve.

That's why my wife and I are drawn to a little town named Pottsboro on the edge of lake Texoma.
To the north of town, outside the city limits there are hills, forest and water.
People are normal there.

Too bad the angle iron got twisted up.
I have lots of hills to mow in my terraced backyard and I try to let gravity do as much of the work as possible.

Here's a house that we looked at.
It was in our price range but was two story and had no garage.
Not what most people think Texas looks like.

Image
https://ka-electronics.com

"States Ordered To Fraudulently Inflate COVID-19 Cases 15 Times Actual Rate"
https://banned.video/watch?id=5efab695672706002f367a0a
"Plandemic/Doctors In Black" https://proaudiodesignforum.com/content/Plandemic.mp4

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JR.
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Re: home improvement turns into science fair projects?

Post by JR. » Sun Aug 02, 2020 10:53 am

mediatechnology wrote:
Sun Jul 26, 2020 12:17 pm
Hopefully you'll get some nice pecans.
I was in a restaurant in Dennison Texas yesterday and they had 2 lb bags of whole shelled pecan halves for $12/lb.
We already had a bunch in the freezer or I would have gotten some.
seems early for this season... my pecans are just now forming
I anticipate your battle with squirrels is going to heat up as fall approaches.
I saw two this morning on the corner lot next door, but they saw me too... :lol:

I have a 4th security camera not in use, but I don't need to aggressively hunt them off my property.

JR
Don't only half-ass tune your drums. Visit https://circularscience.com to hear what properly "cleared" drums sound like.

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mediatechnology
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Re: home improvement turns into science fair projects?

Post by mediatechnology » Sun Aug 02, 2020 11:16 am

I think the pecans we saw were last year's crop.

IIRC the fall crop comes into the stores in early October.
https://ka-electronics.com

"States Ordered To Fraudulently Inflate COVID-19 Cases 15 Times Actual Rate"
https://banned.video/watch?id=5efab695672706002f367a0a
"Plandemic/Doctors In Black" https://proaudiodesignforum.com/content/Plandemic.mp4

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JR.
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Re: home improvement turns into science fair projects?

Post by JR. » Sun Aug 02, 2020 11:35 am

mediatechnology wrote:
Sun Aug 02, 2020 10:48 am
Seeing the 45 MPH sign makes me wish I were in a small town like Hickory.
yup downtown, nowhere MS. Inside city (cough) limits. :lol:
Dallas has begun to suck really, really bad.
There is mass mental illness here in the form of TDS and covid-hysteria.
I suspect the TDS is everywhere but probably worse in Austin with all the liberal/progressive transplants.
The speed limit on our wooded country-like street is only 25 MPH but 1 mile in either direction and its Mad Max territory.
Like Detroit, Baltimore and Chicago it will never improve.

That's why my wife and I are drawn to a little town named Pottsboro on the edge of lake Texoma.
To the north of town, outside the city limits there are hills, forest and water.
People are normal there.
for now... but country mice are friendlier then city mice especially if you are considered one of them, by them.
Too bad the angle iron got twisted up.
it was a lot of work for not much benefit... I could trim a few feet closer to the ditch but not the whole ditch.

I have lots of hills to mow in my terraced backyard and I try to let gravity do as much of the work as possible.

Here's a house that we looked at.
It was in our price range but was two story and had no garage.
Not what most people think Texas looks like.

Image
No garage could be an opportunity to build exactly what you want/need.

JR

PS: One of my two squirrels came back.... He was ignoring me but I couldn't get a clean shot resting the rifle on the roof of my car... moving back to rest the rifle on my trunk lid spoiler alerted the squirrel to my intentions and he ran again... He gave me one almost still shot but I jerked the trigger and missed him. (air rifle scope is sighted in with laser, but I haven't checked for pellet drop over that distance). I probably should aim a little higher. It was a close miss and he scrambled up the tree with his tail spinning furiously. He climbed about 6' up my side of the tree and just sat there. Giving me time to reload. Sadly his camouflage was too good on the dark shady side of the tree and I did not get a good sight on him with his tail not moving. When he did move again he was gone before I could get off a second shot. In hindsight I should have guessed and shot where I last saw him. I wasn't sure if he was tail up or tail down, probably tail down.
Don't only half-ass tune your drums. Visit https://circularscience.com to hear what properly "cleared" drums sound like.

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