slowing down a mag drive 2400...if possible

[CHOMPERS]

You make a good arguement I can't counter it. I am almost convinced I am going to have to play with a pump and ampmeter now

p.s. I am convinced that I am missing a concept somewhere. On one hand it seems right but on the other it still not grasping it.

 

[CHOMPERS]

johnptc is 100% correct. They use the most energy when running wide open at zero head. Centrifugal pumps that is.

At the chemical plant I used to work at each centrifugal pump had an amp meter at each station. Throttle back the discharge and the amperage goes down. Open it up to get more flow and watch the amperage climb.

Not to be confused with "positive displacement" or "reciprocating" pumps which should NEVER be throttled back on the discharge. These are the types of pumps that pump gases like your air pumps.

Throttle back one of these pumps and watch the amperage skyrocket then listen for the relief valve to blow.

And I just saw Volenti's post. Also 100% correct.

You know when there is a good movie out and someone wants to tell you how it ends and you don't want them too

Anyway, thanks for the info.

 

[johnptc]

You know when there is a good movie out and someone wants to tell you how it ends and you don't want them too

Anyway, thanks for the info.

please share the results of your experiment...........

i am going to try it here as well............lets setup a centrifugal pump..monitor current draw and choke the output..............

i always take experimental results first theory second.....

this sounds like the setup bud8fan had at work....

john

 

[Volenti]

Regarding actual data, I have a little 12v magdrive pump running my 10 gal setup (it's actually designed for PC watercooling, high head, low flow) in normal running mode it draws 1.05A, with it's outlet blocked it draws 0.84A. I don't have my AC clamp meter at home so I can't test my other normal AC pumps.

And admitadly it does rattle and complain a bit with the outlet completely blocked...

 

[johnptc]

Regarding actual data, I have a little 12v magdrive pump running my 10 gal setup (it's actually designed for PC watercooling, high head, low flow) in normal running mode it draws 1.05A, with it's outlet blocked it draws 0.84A. I don't have my AC clamp meter at home so I can't test my other normal AC pumps.

And admitadly it does rattle and complain a bit with the outlet completely blocked...

it is a high head pump...rock and roll

 

[repair]

You make a good arguement I can't counter it. I am almost convinced I am going to have to play with a pump and ampmeter now

When you do it take some temp readings so we know if the motor heats up.

 

[johnptc]

When you do it take some temp readings so we know if the motor heats up.

ok i will try that.

i put the amp clamp on one leg of a 3/4hp march pump ( 220v3p)

it read 2 amps open, choked down it read 1 amp


i will next set it up and let it run 30 minutes with a temp monitor..... good question !!!

 

[Bud8Fan]

We never took temperature readings on the pumps at the plant. We just made sure the oil reserve was full.

One would think thought that since the pump is doing less work and consuming less energy with the discharge throttled back that it shouldn't heat up?

 

[johnptc]

We never took temperature readings on the pumps at the plant. We just made sure the oil reserve was full.

One would think thought that since the pump is doing less work and consuming less energy with the discharge throttled back that it shouldn't heat up?

picture is worth a thousand words....

temperature actually dropped when i choked off the output

 

[Bud8Fan]

Good to see this topic finally put to bed. Where is Dr. Joe.