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Increasing RPM's to gain flow 1
- Thread starter mikecabs
- Start date
ClicketyClack
Mechanical
Depends on the pump design, system (NPSH in particular), motor limitations, etc.
Sometimes the system is the limiting factor, sometimes the pump design is the limiting factor, sometimes the motor...
We need more info.
Sometimes the system is the limiting factor, sometimes the pump design is the limiting factor, sometimes the motor...
We need more info.
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1
- Thread starter
- #3
ClicketyClack
Mechanical
You need to consider several things:
maximum stable flow for the pump
maximum RPM rating for the pump
maximum RPM rating for the motor
amount of flow where NPSHa < NPSHr
power of the motor vs RPM
intersection of system curve vs pump curve at varying RPM (keep it close to the BEP)
maximum pressure rating of system components
maximum inlet velocity of the pump
pump configuration (multiple turbines)
minimum submergence
One or more of these items will limit the max speed.
maximum stable flow for the pump
maximum RPM rating for the pump
maximum RPM rating for the motor
amount of flow where NPSHa < NPSHr
power of the motor vs RPM
intersection of system curve vs pump curve at varying RPM (keep it close to the BEP)
maximum pressure rating of system components
maximum inlet velocity of the pump
pump configuration (multiple turbines)
minimum submergence
One or more of these items will limit the max speed.
- Thread starter
- #6
- Thread starter
- #7
ClicketyClack
Mechanical
There is more to it than that. I would call your local vertical turbine pump vendor.
If lower rpm won't work due to high static head, its possible that changing impeller diameter won't work either and you will probably need a different pump in any case.
thewellguy
Electrical
The bowls, impellers and bearings should be fine, however I would be concerned about the H.P. rating of the drive shafts.
without the pump curve in front of us we are all working in the dark. Can you post a copy of the curve so we can see what is going on and then give you meaningful suggestions.
The following link will allow you to post images.
The following link will allow you to post images.
ClicketyClack
Mechanical
Even with just the fixed speed pump curve it's still a shot in the dark.
- Thread starter
- #14
- Thread starter
- #15
And the system curve?
========================================================
I post the images I want to show on to an image hosting website called Image Shack. There are a number of free hosting sites on the net, but you can find Image Shack at,
Go to and find the instructions for uploading an image to their servers. It typically just amounts to browsing your computer for your diagram and clicking the ImageShack button to upload the diagram.
Once the diagram is transferred to Image Shack, their web page will return several examples showing a number of common ways to link your uploaded image to various classes of web sites. Find the example link that looks like this one,
Unfortunately that does NOT work on Eng-Tips as it is, so you have to edit that link.
You should edit your link by removing all the characters indicated by "^" in the following,
[url htp://imageshack.us]
^^^^^^^^^^^^^^^^^^^^^^^^^
[/url]
^ ^^^^^^
leave a space where the equal “=” sign is.
You should now have a link that looks something like this,
Copy and paste that link where you want your diagram to appear in your eng-tips posting.
After you have the link pasted into eng-tips and finished your question or comment, check your work for proper formatting by clicking the "Preview Post" button just below the text box.
If it looks good, click "Submit Post"
=========================================================
========================================================
I post the images I want to show on to an image hosting website called Image Shack. There are a number of free hosting sites on the net, but you can find Image Shack at,
Go to and find the instructions for uploading an image to their servers. It typically just amounts to browsing your computer for your diagram and clicking the ImageShack button to upload the diagram.
Once the diagram is transferred to Image Shack, their web page will return several examples showing a number of common ways to link your uploaded image to various classes of web sites. Find the example link that looks like this one,
Unfortunately that does NOT work on Eng-Tips as it is, so you have to edit that link.
You should edit your link by removing all the characters indicated by "^" in the following,
[url htp://imageshack.us]
^^^^^^^^^^^^^^^^^^^^^^^^^
^ ^^^^^^
leave a space where the equal “=” sign is.
You should now have a link that looks something like this,
Copy and paste that link where you want your diagram to appear in your eng-tips posting.
After you have the link pasted into eng-tips and finished your question or comment, check your work for proper formatting by clicking the "Preview Post" button just below the text box.
If it looks good, click "Submit Post"
=========================================================
ClicketyClack
Mechanical
Can we start a forum on image posting 
If it's not made of metal I'm really not sure what I'm supposed to do with it.
If it's not made of metal I'm really not sure what I'm supposed to do with it.If you can make an image, follow the above instructions to post it.
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