Question for electricians

[DarkBlack]

Nope. My well is even deeper, and I’m using a 3/4 hp pump.
Static level, and gpm desired are big factors

 

[WinterDeere]

Nope. My well is even deeper, and I’m using a 3/4 hp pump.

Interesting. I see lots of charts like this, courtesy of Google:



It seems to show the 3/4 hp pump petering out around 260 ft depth, and only delivering 5 gpm at 240 ft.

 

[DarkBlack]

The THD issue has to do with excess heat being created in electronic parts, due to the non-sinusoidal waveform, I have read. It all feels the same to me when it bites.

Heat, and harmonic distortion can mislead the power supply’s frequency timing.
It doesn’t matter if the supply supply is a switcher, or linear..If the product requires frequency over watching, such as a good UPS system would have, or timing circuits based off of phase angles,.. those devices are likely to see dirty input power as frequencies higher than 60hz. A single repetitive spike might give the UPS a measurement period indicating the input power is 120hz.

 

[DarkBlack]

Interesting. I see lots of charts like this, courtesy of Google:

View attachment 3744711

It seems to show the 3/4 hp pump petering out around 260 ft depth, and only delivering 5 gpm at 240 ft.

That’s a 15gpm pump chart.

 

[WinterDeere]

That’s a 15gpm pump chart.

True. But given the size of today's homes, I think that's a pretty standard size to specify.

 

[DarkBlack]

True. But given the size of today's homes, I think that's a pretty standard size to specify.

Maybe for people who like run lawn sprinklers everywhere.
7 gpm is more than enough for my house. Even if I somehow exceeded 7 gpm momentarily, which won’t happen, my pressure tank, that everyone has, would handle the brief excess demand .
Here’s a 5 gpm 4” pump chart:
3/4 hp circled

 

[WinterDeere]

That makes sense. I assume the big difference between nameplate pump capacities is the size and pitch of the impeller, effectively changing the mechanical advantage?

 

[DarkBlack]

That makes sense. I assume the big difference between nameplate pump capacities is the size and pitch of the impeller, effectively changing the mechanical advantage?

The interesting counterintuitive part, is that for a given hp, a lower gpm pump actually requires more stages and weight and size, than a higher gpm pump of the same series , using the same motor

 

[WinterDeere]

The interesting counterintuitive part, is that for a given hp, a lower gpm pump actually requires more stages and weight and size, than a higher gpm pump of the same series , using the same motor

Yeah, counterintuitive at first glance. But I guess it makes sense when you stop to think about the fact that the lower GPM trade-off is greater lift. You can achieve greater velocity with changing impeller size and pitch, but the greater lift pressure at a given input HP may require more stages to reduce blow-by at a given RPM.

 

[alexinPA]

Tested the power meter this morning. Works fine showing W, A, F. Even catches the surges. Interesting to see how actual W are different from tables provided. One thing I can't explain... My generator is running with low load-about 60w. Turning on ceiling fan and see 2w. Tried a few times.
How can it be? Any thoughts?