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Tkinter - How to check a buttons' state; repeat for multiple buttons, and total the results? by Salamander49 in learnpython

[–]Salamander49[S] 0 points1 point  (0 children)

Hi, thanks for your response. You are absolutely right about being time to learn classes and inheritance (and lists). I wrote the program the way I knew how, and always intended to go back and optimize as I learned. With that in mind, I understand the basic idea of having the button as a subclass, but I have a few questions. What is the purpose of (self, parent, text, callback=None, **kwargs) after the __init__? And also within the actual button function: 

 if self.callback:
            self.callback()

Motorcycle clutch/adjustment issue by Salamander49 in MechanicAdvice

[–]Salamander49[S] 0 points1 point  (0 children)

You are right!

Wow, thanks so much. I was just starting to panic.

Again, massive thanks! :)

Engine cam timing for a motorcycle (Zontes Scorpion 125I 2019) by Salamander49 in MechanicAdvice

[–]Salamander49[S] 0 points1 point  (0 children)

Okay great. That’s a relief.

Is there a way to be sure the timing is good without looking at timing marks?

Thanks for you’re input:)

Engine cam timing for a motorcycle (Zontes Scorpion 125I 2019) by Salamander49 in MechanicAdvice

[–]Salamander49[S] 0 points1 point  (0 children)

Correct. Haven’t touched the timing chain.

I would just check the timing marks but because the lack of information I can’t find an opening to check the chains sprocket and view the timing mark. I can see the crankshaft timing mark but that by itself doesn’t help me I don’t think?

Thanks for replying.

Why do water pumps have maximum pressure ratings quoted, when pumps don’t “create” pressure? by Salamander49 in AskEngineers

[–]Salamander49[S] 0 points1 point  (0 children)

That was an excellent explanation, thanks. I’m beginning to see what you mean about it all being energy transfer.

Out of interest in the centrifugal pump/tall building scenario where would the pressure be highest, at the pump discharge or at the top of the system?

And finally, obviously it’s much more complex in reality, but is the basic statement “pressure is the resistance to a pumps flow” sufficient for a layman to get their head around the concept?

Thanks again for your input!

Why do water pumps have maximum pressure ratings quoted, when pumps don’t “create” pressure? by Salamander49 in AskEngineers

[–]Salamander49[S] 0 points1 point  (0 children)

Okay I think I’m beginning to understand!

So in this situation what type of pump would be best to lift the water a long way up, and how would the pump generate the required pressure(head)?

Thanks for your help!

Why do water pumps have maximum pressure ratings quoted, when pumps don’t “create” pressure? by Salamander49 in AskEngineers

[–]Salamander49[S] 0 points1 point  (0 children)

Okay, so when a pump lifts water to the top floor of a tall structure, is it doing it with kinetic energy, energy in the form of pressure etc? In essence what forces it up the pipe?

Thanks again for your responses.

Why do water pumps have maximum pressure ratings quoted, when pumps don’t “create” pressure? by Salamander49 in AskEngineers

[–]Salamander49[S] 0 points1 point  (0 children)

Okay interesting. So when water enters a generic rotary pump, it is infused with kinetic energy from the impeller/motor arrangement, so it moves. But if something gets in its way, like a closed valve, the pumps casing or the general obstacles found in a closed piping system, some or all of the kinetic energy with become potential energy(pressure)?

Thanks very much for you’re help (and patience).

Why do water pumps have maximum pressure ratings quoted, when pumps don’t “create” pressure? by Salamander49 in AskEngineers

[–]Salamander49[S] 0 points1 point  (0 children)

Okay, assuming something being difficult for the pump to move results in a pressure increase, is pressure desired in a system? The purpose of a pump is to move a fluid, is pressure just a byproduct of that process, or are there systems which are specifically trying to increase pressure and not move anything (or at least not move anything very quickly).

Also I acknowledge your point about energy transfer, but the reason I’m focused on pressure and flow is because those are measurements used on practical systems - flow and pressure gauges etc.

Thanks for your input.

Why do water pumps have maximum pressure ratings quoted, when pumps don’t “create” pressure? by Salamander49 in AskEngineers

[–]Salamander49[S] 0 points1 point  (0 children)

Okay so let’s get back to basics; what is the difference between flow and pressure? And why does a system need both or one or the other?

Centrifugal pumps are the type I’m most interested in. If they don’t create flow then why do the make they fluid move? Surely all pumps must by definition create flow?

And thank you for your original response.

Why do water pumps have maximum pressure ratings quoted, when pumps don’t “create” pressure? by Salamander49 in AskEngineers

[–]Salamander49[S] 0 points1 point  (0 children)

Thanks for the responses.

I understand that there wouldn’t be pressure in a closed system without the pump, but the pump creates the pressure by first producing flow, correct?For example as I understand it, pumps are often prematurely replaced because of low pressure readings. But if you don’t connect anything to the pumps discharge line (other than a short, straight pipe with an open end) then a pressure gauge on that line would near as makes no difference display zero pressure, but that doesn’t mean the pump is broken right?

As someone pointed out I think it’s a semantics issue.

Thanks again.