DIY Rimless Starphire and Stainless Kiddy Pool (PICS!)

pescadero- With the PWM type field current weakening system that my drive has, it wouldn't make a difference in power usage if I used a 3hp or a 1/3hp motor. If 1/4hp motors were availble in 56J in the baldor reliancer series, I would have used it. Using a 1/3hp or 1/2hp doesn't hurt your power draw when you have field weakening ability. The windings have lower resistance and will pull more current for the same voltage across them, but the VFD uses PWM to lower the effective duty cycle time that it's pulling the current. This enables average current (all that matters for power consumption) to be lowered to as low as you wish to go before the motor starts to have excessive phase slip issues. My drive has built in current meters for each leg, so it's very simple to just turn down field weakening until you see current stop dropping, which indicates you reached the point of slipping.

Reed- It's a pleasure to hear from you my friend! What happened with RF after my banning was truely unfortunate. It was such a great board for a long time. I miss how awsome it was when Mike O'Brien would stir the pot of idle minds into a flurry of thought. Someone actually linked this very thread of my tank to the site, and it was locked and deleated... Not exactly a place suited towards free discussion of ideas anymore... You should PM me and setup a time to come down and check it out in person sometime. It would be great to have lunch or something.

Best Wishes, and thank you to everyone for all the kind words!

-Luke
 
Hey Luke, I didn't know you got banned from RF! Saw someone mention you over there just the other day. When are we getting together??? Are you going to the frag swap on the 19th?
 
thanks for the explanation, luke. can you tell me, is field current weakening something that i'm likely to find in the garden variety VFD unit, or is your unit somehow different from the rest. IIRC it was a bit more expensive, so i thought i'd ask.

while i've got your attention, i'd like to ask a couple of more questions about using other motors.

first, do you notice any problem in throttling down your 1/3 HP motor on your tank? the reason that i ask is because my application will be built into an AGA 90, and i'm thinking that i'll have to severely limit the speed of the motor. as i understand it (please correct me if i am misunderstanding this) you have to run your motor at a very low RPM relative to its rated speed in order to keep the water in the tank. in my application i'm thinking that if i used a 1/3 HP motor i'd have to keep the RPM even lower than you do, which would limit the range of usable RPM to even lower values. would this be a problem?

there are a few other potential benefits that might come from using a smaller motor like a 1/8 HP: a wider useable RPM range, and perhaps lower power consumption since you'd be accelerating/decelerating a set of windings that have lower mass than say a 1/3 HP motor. all of that extra energy adds up on the electric bill.

thanks!
 
<a href=showthread.php?s=&postid=12336099#post12336099 target=_blank>Originally posted</a> by pescadero
thanks for the explanation, luke. can you tell me, is field current weakening something that i'm likely to find in the garden variety VFD unit, or is your unit somehow different from the rest. IIRC it was a bit more expensive, so i thought i'd ask.

while i've got your attention, i'd like to ask a couple of more questions about using other motors.

first, do you notice any problem in throttling down your 1/3 HP motor on your tank? the reason that i ask is because my application will be built into an AGA 90, and i'm thinking that i'll have to severely limit the speed of the motor. as i understand it (please correct me if i am misunderstanding this) you have to run your motor at a very low RPM relative to its rated speed in order to keep the water in the tank. in my application i'm thinking that if i used a 1/3 HP motor i'd have to keep the RPM even lower than you do, which would limit the range of usable RPM to even lower values. would this be a problem?

there are a few other potential benefits that might come from using a smaller motor like a 1/8 HP: a wider useable RPM range, and perhaps lower power consumption since you'd be accelerating/decelerating a set of windings that have lower mass than say a 1/3 HP motor. all of that extra energy adds up on the electric bill.

thanks!
Click to expand...


My feeble understanding is: Wether your motor is a 1/4 HP 3600RPM motor or a 50 HP 3600RPM motor, when hooked to the same wetend (IF it were possible!) they would move the same amount of water at full power...you'll just be using MUCH more electricity on the 50 HP motor. Larger HP motors ONLY move more water because you can hook up larger wetends/impellers to them and they have the torque to spin them. If you took the wetend from a 50HP industrial pump and hooked it up to a 1/4HP motor, it wouldn't spin it because the motor doesn't have enough torque to overcome the mass of the impeller in the water.

The MAIN reason for the smaller HP motor is to minimize electric usage....but with the PWM field current weakening, you can (hypothetically) put that 50HP motor on the sequence wet end and draw the same watts as the 1/8HP motor.
 
JCtweaks- That is exactly correct. These pumps are all 1800rpms, but your thinking is right on the money.

The pump doesn't know or care of the hand of God is turning the shaft or a little 1/3hp motor. If the shaft is turning at 1800rpm, it's going to pump the same regardless of the power the motor is rated for or drawing.

In the example with the 50hp motor, I think that size would be very tough to field weaken low enough due to very low resistance windings, but yes, if your drive let you weaken the field enough you could do it. My drive only lets the field weaken to 20%, so I could make a 1hp motor draw the power of a 1/5hp motor, but no further. If your motor was loaded with less than 1/5hp of torque from the pump at that speed, then it would perform no different than the full power of a 1hp motor spinning the pump. The only difference is much reduced power draw.


Best Wishes,
-Luke
 
<a href=showthread.php?s=&postid=12340422#post12340422 target=_blank>Originally posted</a> by liveforphysics
JCtweaks- That is exactly correct. These pumps are all 1800rpms, but your thinking is right on the money.

The pump doesn't know or care of the hand of God is turning the shaft or a little 1/3hp motor. If the shaft is turning at 1800rpm, it's going to pump the same regardless of the power the motor is rated for or drawing.

In the example with the 50hp motor, I think that size would be very tough to field weaken low enough due to very low resistance windings, but yes, if your drive let you weaken the field enough you could do it. My drive only lets the field weaken to 20%, so I could make a 1hp motor draw the power of a 1/5hp motor, but no further. If your motor was loaded with less than 1/5hp of torque from the pump at that speed, then it would perform no different than the full power of a 1hp motor spinning the pump. The only difference is much reduced power draw.


Best Wishes,
-Luke
Click to expand...

Yeah yeah, all of the details :lol::lol:

I guess my "hypothetical" is out the window :lol:
 
<a href=showthread.php?s=&postid=12340422#post12340422 target=_blank>Originally posted</a> by liveforphysics
JCtweaks- That is exactly correct. These pumps are all 1800rpms, but your thinking is right on the money.

The pump doesn't know or care of the hand of God is turning the shaft or a little 1/3hp motor. If the shaft is turning at 1800rpm, it's going to pump the same regardless of the power the motor is rated for or drawing.

In the example with the 50hp motor, I think that size would be very tough to field weaken low enough due to very low resistance windings, but yes, if your drive let you weaken the field enough you could do it. My drive only lets the field weaken to 20%, so I could make a 1hp motor draw the power of a 1/5hp motor, but no further. If your motor was loaded with less than 1/5hp of torque from the pump at that speed, then it would perform no different than the full power of a 1hp motor spinning the pump. The only difference is much reduced power draw.


Best Wishes,
-Luke
Click to expand...
that makes sense, but i'm still having trouble wrapping my mind around one aspect of the problem: ignoring the mass of the motor itself.

let's ignore the torque required to spin the wet end (which is admittedly the largest factor in the equation), because that number will remain constant regardless of which motor we use in our application.

the motor itself has mass, and a measurable amount of energy is required to accelerate and decelerate it. if you're taking a 50HP motor and starting off at standstill, then accelerating it to 1750 RPM, then braking it to 0 RPM and repeating the cycle, some amount of energy will be required to accelerate and decelerate the mass of the motor.

compare the mass of a large 50 HP mtoor to a small 1/8 HP motor. there's got to be significant difference in he amount of energy that's required to accelerate them. the startup energy requirement would be neglegible if you're starting up a pump and letting it run at a continuous 1750 RPM, but in our model we're constantly accelerating/decelerating them. wouldn't it take less power to repeatedly accelerate/decelerate a motor with lower mass? or is there some efficiency aspect to the equation that i'm just missing?
 
Fortunately for our application, we are staying with the 56J motor frame size. The weight differences in the rotor between the largest and smallest HP versions of this motor are negligable.

However, if we were to have a much more massive rotor weight, it would make very little difference if we used it to our advantage rather than fighting it.

The energy we put into the system to accelerate the rotor has not been lost, it is stored in a form of kenetic energy. Say our ramp rates are set correctly so that we are letting the pump work be the force which slows the motor for us when ramping down. If you had a heavier rotor to accelerate, you simply quit powering it a second or two sooner than you would with a lighter mass rotor, and as it coasts down, you have released that same energy you spent in accelerating it towards pumping water. If you model it as a flywheel, you can see that it's merely an energy storage phase, and not a loss at all if you configure your system to work with it.

However, since the full line of 56J frame motors are roughly the same rotor mass, it doesn't make a bit of practical difference for this application.

Best Wishes,
-Luke
 
does any one know if there a motor it fit the dart pumps? what size case that is 3 phase?

How are you ordering just the pumps caseinns .. you got a number to call which company i didnt think Sequence sold derict.... I have my whole sale stuff so i should be able to get some parts


Do you have list of part number to oder? thx man
 
very cool thread, I wish I would have seen it before the pictures went down.

I can't believe you actually had to throttle it back below 60hz. I was looking forward to going beyond that for higher flow (just for the cool factor) but I guess the eductors helped there. The phase converter in the VFD is cool I was thinking I would have to have a separate one for that. It’s been awhile since I used one I guess. This is going to be a lot easier than I thought.

Also thank you for the correct motor type to fit the hammerhead pump.
 
<a href=showthread.php?s=&postid=12479833#post12479833 target=_blank>Originally posted</a> by Northside Reef
very cool thread, I wish I would have seen it before the pictures went down.
Click to expand...

Ditto.

Any chance of re-linking the pics?
 
I plan to re-host a bunch of pictures when I get my new website up and running.

I will even take some new ones :)

I have a new friend who does interior design work who is going to do my rock/coral layout with me. At the moment it still looks pretty much like somebody threw a big pile of rock in without looking, then set corals wherever was easy to reach. Then I won't be so ashamed to do a full tank shot or two. :)
 
Luke, can you tell me what model of programmable timer relay you ended up using?

I'm looking for a programmable timer relay with a digital countdown display (maximum cool factor), and analog control inputs (ease of use), similar to the one that you described using to control the timing interval on the VS- Mini.

I've looked around in a few industrial control catalogs, but I've come up empty handed when trying to find something that has both the digital countdown display AND easily tweak-able analog control inputs/dials. I was hoping to take a peek at your photos to catch a glimpse of what you were using, but alas... there are no photos.

Can you point me in the right direction? A brand name and model number, and perhaps a photo would be greatly appreciated.
 
Ask and you shall receive my friend! I'm sorry the pics are all down, I will soon have a new website up with photos.

The "E" on the left means "Every", it has other logic functions you can set it to if you desire, but "Every" seems to work best for me.

The "S" on the far right means "Seconds", and it can also do minutes, hours, days, and maybe weeks and months too, I don't remember.

Then the inside number dials set the interval time quanity. You can see mine is set to make a wave every 8 seconds.

I LOVE analog settings for a timer! It takes me 2-3 seconds to make a change when I want, and I know that power outages and things can't effect my settings.

I hope the picture helps!




Best Wishes,
-Luke
 
Hey, Superman:

[welcome]

Looking good Luke...when are we getting together? Thought we were going to be doing some air flow testing with Sherman! :D
 
dido on the pics...wish I could see them. Hope you post some new ones or alink to your web site soon. From what I read, it sounds amazing and very unique.

Great Job!!!!
 




These are the ballasts for the 4 x MH, and the power LED ballasts. The ballasts for the 12x 54w T5HO are inside the lighting assembly.




I need to take more recent pictures. Everything looks different on the setup once again... You could say that I enjoy finding new solutions to innovate and improve the setup.

Best Wishes,
-Luke
 
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