home improvement turns into science fair projects?

Relax in southern comfort on the east bank of the Mississippi. You're just around the corner from Beale Street and Sun Records. Watch the ducks, throw back a few and tell us what's on your mind.
User avatar
mediatechnology
Posts: 5442
Joined: Sat Aug 11, 2007 2:34 pm
Location: Oak Cliff, Texas
Contact:

Re: home improvement turns into science fair projects?

Post by mediatechnology »

JR. wrote: Thu Feb 13, 2020 12:01 pm
mediatechnology wrote: Thu Feb 13, 2020 11:53 am I don't know if the switcher blob is galvanically-isolated or not.
I doubt it.

The audio "silent switcher" has a ground connection from USB input to bipolar output.

Does the USB 5V outlet on the wall plate have a connection to safety ground?
I don't know but it would be easy to check.
UL woud probably like a safety ground bond, my experience with random house/outlet wiring suggests double insulated could be safer in practice.

JR
From Leviton:
Thank you for contacting Leviton tech support. The USB/DC ground is isolated from the AC ground (strap). The dielectric barrier between AC ground (strap) and USB/DC ground is tested per UL standard (1310). (emphasis added.)
I think I like it floating since it is more transformer-wall-wart-like.
User avatar
JR.
Posts: 3700
Joined: Sat May 24, 2008 7:21 pm
Contact:

Re: home improvement turns into science fair projects?

Post by JR. »

yup 1310 is apparently the UL standard for class 2 double insulated, 2 wire skus...

JR
Cancel the "cancel culture", do not support mob hatred.
User avatar
JR.
Posts: 3700
Joined: Sat May 24, 2008 7:21 pm
Contact:

Re: home improvement turns into science fair projects?

Post by JR. »

Sump pump only ran 15-20 minutes this AM so ground water is subsiding a little.

I was little worried when I upgraded to 1/2 HP from previous 1/4 HP sump. I had noticed that with the former 1/4HP sump the extension cord got a little warm, not enough to be a concern but evidence of the current draw.... I expected logically that the new 2x larger pump would draw more current and cause more heating. In a pleasant surprise if anything the cord is subjectively cooler... I will speculate that the new motor is more efficient, I don't think I have specs for the old sump pump that was purchased a few decades ago. 8-)

JR
Cancel the "cancel culture", do not support mob hatred.
User avatar
JR.
Posts: 3700
Joined: Sat May 24, 2008 7:21 pm
Contact:

Re: home improvement turns into science fair projects?

Post by JR. »

In no great surprise, the old sump pump that still worked has a readable power plate calling for 9A. Thus the warm extension cord... New pump despite 2x HP does not seem as current hungry.

[edit- while I wasn't paying attention it looks like they started rating motors by HP not current... my old 1/4 HP motor calls out 9A, the new 1/2 HP motor only specs HP, but if I look up current draw for 1/2 HP I get a similar 9A, so 2x power for same current as old school... got to love technology /edit]

I am resisting my inclination to redesign the second water level switch, before it arrives... somebody stop me.. :lol:

Multiple technologies that look interesting, bouncing ultrasonics signals off the water level, laser distance meter, and perhaps capacitance detection. My old idea of sensing the line cord draw still sounds good for safety shut off... But first things first, lets see how the new level switch looks, due in next week.

JR
Cancel the "cancel culture", do not support mob hatred.
User avatar
JR.
Posts: 3700
Joined: Sat May 24, 2008 7:21 pm
Contact:

Re: home improvement turns into science fair projects?

Post by JR. »

IMG_20200224_151248447.jpg
I finally have reliable (I hope) cybernetic control of my crawl space sump pump... The tethered level switch (that sucks) is cable tied up at attention so hard on... The add on smart level switch is attached to the side of the pump by the discharge outlet... I put some coarse netting (like onions come in from the store, actually exactly what my onions came in) around the bottom intake port to keep sticks and small animals out.

I put the pump into the hole without the bait bucket, and it fit a little better but hole could still stand to be a little deeper.

It appears that I now have smart turn-on, and better yet smart turn-off... 8-)

Good progress.. It seemed to short cycle a few times after the first draw down but that may just be the nature of my sub-surface water flow... It's raining right now, so mo water coming. :lol:

JR
Cancel the "cancel culture", do not support mob hatred.
User avatar
JR.
Posts: 3700
Joined: Sat May 24, 2008 7:21 pm
Contact:

Re: home improvement turns into science fair projects?

Post by JR. »

well that didn't take long... didn't turn on when water level hit the low float today.

The common customer complaint is that the controller fails stuck on and burns up the pump motors...

For now I am manually switching it again... :oops:

I may wait until next weekend to pull it out and troubleshoot... but might investigate this sooner.

My idea to sense current draw sounds better and better... :lol:

JR
Cancel the "cancel culture", do not support mob hatred.
User avatar
mediatechnology
Posts: 5442
Joined: Sat Aug 11, 2007 2:34 pm
Location: Oak Cliff, Texas
Contact:

Re: home improvement turns into science fair projects?

Post by mediatechnology »

I remember a stove vent hood design that used motor current to detect a blocked filter.

Do you have any current measurements of it running dry vs wet?
I realize that it may not have stopped raining enough for you to measure that in situ.
User avatar
JR.
Posts: 3700
Joined: Sat May 24, 2008 7:21 pm
Contact:

Re: home improvement turns into science fair projects?

Post by JR. »

My original current sense split core transformer saturated at 5A and my pump is rated for 9A at max load. I have since found some 100A transformer/sensors. The typical form factor is 1000:1 step down. 9A max draw should generate 9mA output, that seems workable.
Image
Image
another is 50mA output @ 100A.

I am resisting the temptation to make this microprocessor controlled, manually turned on with automatic turn off seems reasonable.. an alternate is to generate a several hour delay so it can test for presence of water to pump, while active. With a smart micro control I could adaptively set the interval for sampling based on results.
===

Of course I still need to drag the sump pump out of my crawl space and determine why it stopped switching...in case it is something obvious and simple. The newer high output pump only took about 10 minutes to clear this morning's accumulation of crawl space water. It is not as loud as my old pump when pulling air, but I can hear it from inside the house if I stand directly above where it is operating.

JR
Cancel the "cancel culture", do not support mob hatred.
User avatar
terkio
Posts: 304
Joined: Thu Feb 07, 2019 3:17 am
Contact:

Re: home improvement turns into science fair projects?

Post by terkio »

JR. wrote: Wed Feb 26, 2020 8:49 am It is not as loud as my old pump when pulling air.....
JR
Hey.
What about detection based on loudness, sound ?
User avatar
JR.
Posts: 3700
Joined: Sat May 24, 2008 7:21 pm
Contact:

Re: home improvement turns into science fair projects?

Post by JR. »

terkio wrote: Wed Feb 26, 2020 10:02 am
JR. wrote: Wed Feb 26, 2020 8:49 am It is not as loud as my old pump when pulling air.....
JR
Hey.
What about detection based on loudness, sound ?
In my judgement that would be unreliable... my old sump pump made a racket when it pulled air, because it was sitting in a plastic bait bucket that apparently made it louder... the new pump is much quieter and I have to really listen hard, by standing in my bathroom to even hear it. The old pump was clearly audible in my main room even with the TV playing loud.

Now I am only hearing it intermittently pulling some water, so if it was completely dry, it would be even quieter.
==
I am about ready to pull it out and test it in a plastic garbage can as soon as it stops raining.

JR
Cancel the "cancel culture", do not support mob hatred.
Post Reply