Dolphin Ampmasters
 

Hi,

I currently have some 1/2 horse jacuzzi pumps,wich are rated at aprox 45 gpm,and draw about 4 amps each........i have read abit about the ampmasters drawing a max of between .8 to 1.8 amps max at only 1/15 horse,and almost matching them for volume.

I have heard that these specs are not exactly true as far as true power consumption for the dolphins,is this possible without being false advertising ?

Could any of you electricians enlighten me?
As i wish to purchase one in the near future.

Thanks,Marc.

Dolphin Ampmasters
 

Hello,

Actually Darren you have the meter to test for power consumption, right? Maybe if you don't mind and have the time to clear this thing up since you have the Ampmaster running?

But I agree with your doubts too. The Emerson motor on the Ampmaster is identical to my 1/3 HP on my table saw. Now the table saw motor is about 5 times more powerful but is a 15A motor. So even 15A/5 = 3A. I know things probably does not follow a linear relationship but 3A is quite a bit high compared to what the Ampmaster is rated at and it's identical motor brand and housing and such.

Dolphin Ampmasters
 

I'll hook it up today and see what I come up with.

didn't even think about trying it.. lol..

oh wait.. I'll hook all the plumbing back up n fill the sump with water first.. then run the pump.. lol

Dolphin Ampmasters
 

I bought one on Saturday to run a closed loop I'll be looking for some opinions on plumbing it in Darren.

Dolphin Ampmasters
 

Marc Titus,

One thing to concider with these pumps is that they run at a lot lower RPM than a table saw is required to run at. But then again you use various pulleys to increase the RPM there. The housing and such isn't a good indication of how the inner parts of the motor is set up. You will need to know how many windings and such there is inside.

Titus,

If you take a look at the CSA manufacturers plate on the side of the motor itself you will see that the max Amperage is 1.3A. And it's RPM is 1725. I highy doubt a well known manufacturer of motors such as Emmerson will falsify these numbers to CSA.

I can see the wattage numbers being different but not much. If you multiply out the Volts and Amps on the side of the motor you get 149.5 VA(Volt Amps). This is usually not equal to Watts. Unless it is a perfectly efficient system with no resistance or inductance(which for the most part is impossible). With this being a motor tho it should be almost 100% efficient. So you could say that VA is very close to Watts.

In a nutshell I'll put money on this pump drawing 150W like they say. Or very darned close to it.

I'll test it a bit later with my transducer to make sure. Have to re-wire it a bit.

[ 20 May 2002, 12:12: Message edited by: DJ88 ]

Dolphin Ampmasters
 

Have you had a chance to test this yet Darren? Inquiring minds want to know :D .

Paul.

Dolphin Ampmasters
 

Here is the numbers.... Not good....

With a load(ie pushing water) here are the results.

at initial startup. Motor draws 2.8 amps (RMS) after five minuutes it dropped to about 2.0 amps. (RMS) Not the 1 amp quoted. Not even close.

According to Dolphins website the pump's current draw will decrease as the head pressure goes up. Well I never even got down to the highest amperage they quote.

As for wattage consumed. Here is another kicker..

At initial startup 244Watts 120VAR's.

after 1 min 230Watts 106VAR's

after two min 226Watts 103VAR's

after five minutes 222Watts 101 VAR's

I kept measuring beyond five min but it leveled out at 222-224 Watts.

Hmm Me feels like I was taken for a ride now..

all measurements were done with a WATT - VAR transducer and a fluke 87 series III multimeter.

If anyone wants the accuracies/error factors of the meter or transducer let me know and I will get them for you.

I'll just say the error factor on both is under 0.1%

:mad: :mad: :mad:

I am going to go take a few deep breaths.. see ya later.. ;) :D

[ 24 May 2002, 13:43: Message edited by: DJ88 ]

Dolphin Ampmasters
 

As an addendum. I am running my entire system with 1.5 " PVC. Not reducing the tubing anywhere.

Dolphin Ampmasters
 

Talked to Tom Briscoe Jr. at Dolphin just now, thanks Troy for using your dime. :D and it turns out we are both right, kinda.

The wattage consumption that Dolphin is claiming is what the motor actually draws if you test AT the motor. Not at the wall. The difference in wattage is due to line losses from the motor to the wall. So in effect we are BOTH right. The motor uses 150W but from the wall 222Watts is used. The wattage difference between the two is lost due to resistances in the wiring from the wall to the pump motor.

I am betting that you will find this with all pumps and equipment sold to the hobby. I am going to test Troy's MAK4 in a few minutes just to find out for sure.

Talk later.

[ 24 May 2002, 15:02: Message edited by: DJ88 ]

Dolphin Ampmasters
 

Hey Darren, this is a interesting result. let me see if I get this right.. the aquarium pump manufactuers are rating the power like that to make it look better than a .. oh say a hot tub pump that is rated the same but 1/2 the price?

am I thinking along the right path?

Steve

Dolphin Ampmasters
 

Umm actually no. The thing is by using this pump you are getting a much more efficient motor than what is probably in a jacuzzi pump. So in the end you are getting one of the best pumps out there. It is just that the actual power consumption is not as low as first thought. It is still low. but..

With that said.

Ok so a MAK4 does the following.

startup 137W

running after a couple of min 123W 32VAR

current draw was 1.1Amps

This shows you that what a manufacturer claims isn't the same. When a manuf says 95W as with the MAK4 that is AT the motor. Not from the wall.

Dolphin Ampmasters
 

Hmm, that really doesn't make sense, the resisitve properties of the line must be quite high to cause a increase in wattage of that magnitude. I kinda doubt the explanation Dolphin gave you. Maybe a electrical engineer can jump in and give us a guiding light.

<font size="2" face="Verdana, Helvetica, sans-serif">

Dolphin Ampmasters
 

thats what I was thinking Bryan, 77 watts seams like a awfull lot of power to be disapated as heat in a power cord.

That means your power cord is consuming 0.64amps Darren.. does that make sence to you? I would think it would be a little hard to hold on to the cord for more than a fraction of a second due to the heat that is being throwen off by the cord if this is the case.

if the dolphin pumps is as I remember it should be a centrifical pump..am I right? and are you using it to push water back up to the main tank? if so I would think that the ratins dolphin used are for 0 head. so if you had the pump at the top of your tank and drew strait out and put it strait back it you would probably get there numbers.. the more head ou put on it the harder the moror has to work.. and the more power it draws. the electric motors used in that type of a pump are a constan speed type motor so as increased head pressur caused the impeller to slow down the motor will draw more curent to bring the speed back up to its rated rpm. I will go through my notes and get you the proper terms on this type of speed controle if you want but basicly thats how it works.

Steve

[ 24 May 2002, 20:00: Message edited by: StirCrazy ]

Dolphin Ampmasters
 

Give me a half hour and I'll post the Wattage, VA and VAR results. :D

Dolphin Ampmasters
 

Ahhh.....Thats better.

Maybe ill stick with the pool pump,as it keeps volume after being re-routed ect.

Thanks Darren.

Dolphin Ampmasters
 

Marc, You'll be using probably twice the power with the jacuzzi tho. Why go that route? 1/2 the power for more water volume..

Steve,

I know the numbers don't add up. I think they are not telling us about all the losses in the motor itself. Still tho this pumps pushes more water than anything else around. I'lls till use it but know I knwo what the 'real' numbers are and won't fool myself into thinking it is less than it is.

When I was told to measure what the motor is using they wanted me to measure across only a couple of poles in it. Right there it shows we aren't taking into account the whole load the motor is placing on your house circuitry.

I didn't liek the explanation but I have a feeling(after testing the MAK4) that it will be the same for everything I run these tests on. Which bites.

I can understand a manufacturer supplying the bench ratigs. BUt once it is assembled there shoudl also be ratings for the useable power ratings.

I was given a good analogy yesterday. When you buy a vheicle and are told it has x number of horsepower that is a bench rating. Once you slap it into a vheicle you lose a lot due to transmission, frictional losses etc etc etc. It is the same with these and any other pumps. There are losses. frictional, resistive etc. It just bites we are lead into believeing that the numbers we are given are the ones we actually see in real life.

As for the losses the ampmaster has I'd assume that it is more than line losses. Friction will play a big part in it. Whether it is due to friction in the windings, resistence of the water fom wanting to move or what ever. THey are there.

Dollar for dollar tho to get the equal in water volume moved you'd need to run three MAK4's which cost $269 a piece. You'd be using more power and two of these things is more expensive than one Ampmaster.

In the long run I will still use the ampaster. tho I am not happy with the little 'deception'.

sigh waht can you do. Manufacturers have us kinda over a barrel. Either we use the pumps they give us or we dont' use anything at all. We can use jacuzzi pumps but I'd hazard a guess they use a heck of a lot more power than the pumps we are using now.

If the plackard onthe jacuzzi says it draws 4.5 amps I'd bet it draws a lot more. I was told by DOlphin it is the standard in the industry to show bench ratings and not actual ratings. so I doubt the manufacturer of the jacuzzi pumps will be different.

clear as mud???

Marc we will have to test one and see for sure.

[ 25 May 2002, 11:17: Message edited by: DJ88 ]

Dolphin Ampmasters
 

Darren, hehe your telling me.. althought it is a little different for a car.. all the losses in a care are after the motor that is rated.. and it is not hidden that it is flywheel horse power.

I agree that the Dolphin looks like a cool pump also.

JFYI, hot tub pumps are never rated at 0 head so infact there out put in all realaty will probably blow the dolphin away.. here is a example of my pump on my hot tub to show you what I mean. mine is a little more powerfull than a dolphin but it shows you how they are rated.

HP 1.5
Volts 120/240
gpm@30 ft.(head) 127
gpm@40 ft.(head) 105
gpm@50 ft.(head) 50

so that is over 7600gph @ 30 feet of head ( I want to see Titus put that baby on his tank :D :D ), and it cost me 180.00 for motor and pump. it does use a lot of power though.. 8.2 amps on high speed and 2.2 amps on low speed using 220 power (this is MAX DRAW ratings.. now wattage rating whatsoever) and is a little more noise.. not to bad though.. a insulated cabnet would quiet it right up.. the best thing is thease pumps are designed to run 24/7 for 10 years. in the situation of a sump in the basement I think this would be the way to go on a big tank.

the dolphin pumps look very simuler to a hot tub pump motor but what I suspect is that it is a smaller power motor with a smaller pump end..and you are paying for the quietness of the unit. hell it is still better than any other pump in the fish industry from what i have seen though [img]smile.gif[/img] another thing I noticed is they the aquarium industry is infatuated with wattage to the point of what we have seen here.. using almost useless #'s for the sake of compatition.

I almost wonder if I could buy the same thing for 1/2 the price at my local hot tub dealer... hmmm are there any #'s stamped in to the plastic pump end on your dolphin? would most likely be on the outside of the impeller housing.. I get good deals at the local hot tub place maby I could order the pump ends in.. then it is just a matter of getting a good pump to hook it to [img]smile.gif[/img]

Oh I am going to see if they have any pumps there that are 1/2 HP or less so I can see if they would work also [img]smile.gif[/img]

Steve

[ 25 May 2002, 11:43: Message edited by: StirCrazy ]

Dolphin Ampmasters
 

The one thing is to concider with a jacuzzi pump is the power consumption. That was a main selling point for the ampmaster to me. if I am using 222W to get 3000GPH then so be it. TO get those same numbers(or slightly more) i'd need three pumps that comsume similar wattage with one pump only. THe MAK's are thelowest consumers but two of those cost more than the ampamster.

I am gonna test some 4MD's if I can soon.

Those are some big numbers tho.

After testing a few more pumps now I am betting those amperage numbers you have if they are off the plate on the pump or manual are gonna be a bit higher.

Dolphin Ampmasters
 

naw they were actualy lower, I had a guy come out and redo my controle box (some bad wiring from the guy who owned it befor me was causing it to draw more power and trip the breaker pluss I put a new seal in the pump end.. the previous owners never watched there water quality or did any maintence from what I have seen) now under full load it only hits 6.9 amps, and that makes 400 gal of water boil :D

I totaly agree that the dolphin is a good pump and the 77 watt diference.... big deal it still kicks a$$.

Steve

Dolphin Ampmasters
 

Hello,

Wow, what a great discussion. A few comments:

1) I can not imagine the power cord be dissipating "that much" power. It is impossible for the cord to have enough impedance to cause that much of line loss.

2) I believe Steve was looking for the word "induction motor", which I think is what the Ampmaster and pretty much all of the pump motors we see are using. These motors do draw more power as the load is increased until the peak "pullout torque" or "breakdown torque" has been reached.

3) I do not like it when manufacturers are not telling the whole truth. This is the same in the audio industry. However, for the very few high end companies they do tell the truth.

4) And yes, the Ampmaster is still a good pump.

Dolphin Ampmasters
 

<font size="2" face="Verdana, Helvetica, sans-serif">by this do you mean speakers and such Titus? if so how knoldgable are you in this area? I am looking for new ones for my truck.

Steve

Dolphin Ampmasters
 

Darren, I am interested in your MAG7 and MAG9.5 tests today. After reading your tests of the Ampmaster (which I drool over) I was immediately curious of the power consumption of my pair of MAG pumps, which are also a 7 (skimmer) and 9.5 (circulation)

I am just wondering if it wouldn't be more energy efficient to just use a larger pump like an Ampmaster to do both tasks for me?

Dolphin Ampmasters
 

Hello Steve,

I'm an audio fanatic. That's why I did EE. What I was referring to was mostly the amplifiers and speakers. If you want to discuss these off-topic stuff, you can e-mail me.

Dolphin Ampmasters
 

Hi. Been lurking here for a while but feel I have to jump in on this thread.

It is standard to measure amp draw on a power lead directly at the connection to the motor.

If the motor manufacturer's (Emerson) amp rating on the nameplate is 1.3A and you are drawing 2+ amps the motor is in an overload condition and should heat up and kick out the internal overload. If this isnt happening, I would suspect that the test method is off - perhaps a false reading re: true rms. The motor can not run properly in excess of the manufacturer's ratings no matter what is attatched to it.

"The thing is by using this pump you are getting a much more efficient motor than what is probably in a jacuzzi pump"

- ummm, not necessarily. Motors such as these are very similar in efficiency - you might be getting a more efficient mating of pump and motor at the particular operating range.

".. the more head ou put on it the harder the motor has to work.. and the more power it draws"

Actually, with centrifugal pumps it is the opposite. At zero head the pump is moving the most amount of water, is working the hardest, and is drawing the most power. As the head increases, the flow decreases so the pump is moving less water and the load decreases which = less amps.

"If the plackard onthe jacuzzi says it draws 4.5 amps I'd bet it draws a lot more"

No, it cant draw more than the specs on the motor
sticker. The motor on this type of pump will probably have two ratings amps and service factor amps (sfa) and will draw close to the max sfa numbers.

"JFYI, hot tub pumps are never rated at 0 head so infact there out put in all realaty will probably blow the dolphin away."

Most centrifugal pumps will be "off the curve" at zero or very low heads, try to pump too much water, and overload. Thats why you dont get a 0 head rating.

"I can not imagine the power cord be dissipating "that much" power. It is impossible for the cord to have enough impedance to cause that much of line loss."

I agree. Look elsewhere I think.

Jim

Dolphin Ampmasters
 

Jim, welcome aboard and join in more often.

Dolphin Ampmasters
 

Hey Jim nice to see ya. pumps is a big part of my work, we even had to build gear pumps and centrifical pumps on the layth from scratch.

I agreed with your post except for two things (and they were both kinda the same) please do think bad of me as I know computer chats can seam cold but I think you are thinking of another effect that is a result of a centrifical pump not working right. well maby I can explain this with out making anyone mad.

Oh and don't mind my spelling I am a engineer not a english teacher :D :D

<font size="2" face="Verdana, Helvetica, sans-serif">not realy, if you look at any centrifical pump flow vs/power vs/ head pressur tables you will find it is the oposat of what you have just stated to a point. as you start raising the outlet pressure yes the flow goes down but the power draw goes up as your impeller is now trying to move in a higher pressur whare the water is resisting the movement. BUT as you reach the limit of the pump you will get a increase of shear between the moving water and the stationary water which will cause cavatation and can airlock your pump (in extream cases) in any case this will also cause heat and if it goes on to long it can destroy your pump.

<font size="2" face="Verdana, Helvetica, sans-serif">the reason you don't have a 0 head rating is because any pump will pump at 0 head. Hot tub pumps are not rated at 0 head because you will never have a hot tub with that low of a resistance.. with all the nozzels there is a lot of head generated so a 0 head rating would be totaly useless in the hot tub industry. If we go y your statment any power head in a tank should trip out.. this doesent happen.. because ) head is the easyest state to pump in.
as you add head to the equasion you add pressure to the inside of the casing which inturn creats the effect of making it harder to pump. when this happens the pump speed slows down and you get less out put. the motor will try to maintain the rated speed but if the head gets higher it can't and does its best at a slower speed, hench the lower output at higher heads. the part you are right about is that when you reach a point of high head pressure that the impeller in the pump isn't rated for your shear streeses insidde the pump become so great you generat slip. this causes the impeller to overspeed and if the motor is equiped with a overspeed trip it will trip, if not it will spin fast with no output and overheat untill it either burns itself out or the motors thermal overloads cause it to shut down.

[ 25 May 2002, 21:53: Message edited by: StirCrazy ]

Dolphin Ampmasters
 

Hi Steve. No offence taken but I think you should check your theory. What you are saying is more applicable to positive displacement pumps (gear, vane, diaphragm, piston) but not centrifugals.

"BUT as you reach the limit of the pump you will get a increase of shear between the moving water and the stationary water which will cause cavatation and can airlock your pump (in extream cases) in any case this will also cause heat and if it goes on to long it can destroy your pump."

Cavitation occurs when the pressure at the inlet of the pump is reduced to the vapor pressure of the fluid being pumped and the fluid "boils". This occurs at low heads/high flows or when there is a restriction in the inlet piping. It doesnt generally occur at low flow/high head. Check the npshr vs flow on a pump curve. The heat produced in a pump at low or no flow is from friction not cavitation.

"If we go y your statment any power head in a tank should trip out.. this doesent happen.. because ) head is the easyest state to pump in."

Umm, yes it does happen.

"the part you are right about is that when you reach a point of high head pressure that the impeller in the pump isn't rated for your shear streeses insidde the pump become so great you generat slip. this causes the impeller to overspeed and if the motor is equiped with a overspeed trip it will trip, if not it will spin fast with no output and overheat untill it either burns itself out or the motors thermal overloads cause it to shut down."

No, at high head/no flow the motor could run forever. What happens is the water overheats from recirculating in the pump head and eventually melts (if its plastic) and siezes - then the motor quits : ) Also, if you follow your line of reasoning, a motor by itself (no pump-no load) will over speed. Well, ac induction motors cant really over speed - rpm is a function of number of motor poles and frequency

Jim

[ 25 May 2002, 23:18: Message edited by: JimE ]

Dolphin Ampmasters
 

positive displacements slow down all right when they is a restriction.. then they shut down :D seen some one shut a pump dischagre by accadent and it wasn't pretty :D :D
I did type that wrong was mixing stuff up hehe when I talk about a centrifical pump slowing down, I should have said it is a small amount and it usaly is right back up to speed. as the amount of shear inside the pump will increase lowering your output. it is not lowered by the motor slowing down.. sorry for the confusion..

"Cavitation occurs when the pressure at the inlet of the pump is reduced to the vapor pressure of the fluid being pumped and the fluid "boils". This occurs at low heads/high flows or when there is a restriction in the inlet piping."

yup it also occures inbetween the impeller and the viens when the pump is reaching its stall out speed or when you are trying to pump a fluid that is to viscus for the style of centrifical pump you are using.

"The heat produced in a pump at low or no flow is from friction not cavitation."

yes the heat is from friction of the water shearing (I didn't stat this to clear) but in adition to the heat from friction you can also end up with cavatation inside the pump on the low pressur sides of the stationary viens which accelerates the wear inside the pump.

you stated that a centrifical pump will trip out at 0 head. you have me totaly baffeled with this statment
I have one in my fresh water tank and it never trips out.. I don't understand why you think it would.. I am sure lots of people have power heads going in there tanks constantly with out them tripping out all the time.. heck my power filter is 250 gph it is running at 0 head all the time and it never trips out.

unless maby we are having some semantics about the term "0 head".. of course 0 head would be impossable as you have outlet piping of the pump its self, but when I use the term 0 head it is to refer to a state that you would get if you put the pump submerged in a tank of water so it draws water directly in its intake and discharges directly back into the tank with out having to lift the water

"No, at high head/no flow the motor could run forever. What happens is the water overheats from recirculating in the pump head and eventually melts (if its plastic) and siezes - then the motor quits : )"

I know what you are saying but if you dead head you will start to generate heat.. aat a point the water inside the casing will start to boil off lowering the resistance of the water, this will make more heat and destroy the pump if the motor doesen't trip first. "untill it either burns itself out" was refering to the pump.. sorry I didn't make that clearer [img]smile.gif[/img]

I thik we are pretty much on track (some quick typing on my part with out reading it over first) but there is still confusion on this 0 head thing, I have had lots of power heads over they yease and they all ran in the tank fine.. so unless it is a confusion like I stated above you have me confused on that one..

Steve

Dolphin Ampmasters
 

6.9 amps.. man you could do damage with that.. :D

As another aside. I am gonna test my MAG7 and MAG9 today or tonight.

Hmmm new career? ;)

Dolphin Ampmasters
 

Hi,

Since the ampmaster pump is still relatively new, I think the pump is still a bit tight (i.e. tight bearings, new brushes and etc). Give it about 200 hours or so of break-in...then re-measure.

I agree that if the ampmaster is drawing more current than what it is registered to draw, then you might be having some problems. It is illegal to falsify power ratings -- otherwise what is the point of posting power ratings when you know that they are false.

- Victor.

Dolphin Ampmasters
 

The current measurements I took were True RMS. As an FYI. I won't go into the pump theories.

How I was told that the wattage consumption and current numbers were obtained was by measuring one of the poles in the motor itself(the number one pole)to me this means only part of the motors draw is being tested. If I am wrong here someone correct me.

As an FYI. ok I don't have the first clue about how these motors/pumps operate when it comes to cavitation. but I just turned my Ampmaster on and measured the current draw as I varied the head pressure by opening and closing the ball valve immediately after the pump. As I increased head pressure(closed the valve and increased resistence to flow) the current dropped. I don't know what happens inside all I know is the numbers I have in front of me. The more head pressure the lower the draw. I don't explain em. I measure em. :confused:

I still don't know where the differnece in numbers is arising from but I have a feeling it is partially due to line losses(very minimally IMO) and due to the actual operation of the motor off of the test bench. When hooked up in a real world situation it is pulling 2-2.5Amps. and 222Watts after a short "warm up" period.

If I could take it apart and bench test it I would. But I paid $500 for this puppy and if I take it apart I void my 9 year warranty.

As I test more pumps I'll post the data. Jim, Steve. Keep talking. As you talk the more I learn.

Victor,

I agree there will be a break in period as tehre is with anythign mechanical, but enough to pull twice the rated current??? :confused:

I still think due to the set up of the motor measuring the power and current of one pole on an electric motor is not giving us all the numbers. As the motor spins will ther enot be a period where current is applied to more than one pole? not full "power" but a partial draw? if this is the case then won't the draw be more than the 150W and 1.3Amps that ONE pole draws?? I am trying to go back and remember my AC motor theory. and not having much luck at it.

Dolphin Ampmasters
 

Victor.

Not much to break in on these types of pumps - only 2 ball bearings - pretty negligable.

Darren.

"As I increased head pressure(closed the valve and increased resistence to flow) the current dropped. I don't know what happens inside all I know is the numbers I have in front of me. The more head pressure the lower the draw"

Exactly. I think someone pointed that out already : )

IME the only way you are going to get an accurate measurement at the low amps is to run directly through the meter - the 87 is rated for 10 amps I think. (double check yourself to settle fears of exploding meters : ) Disconnect a power lead at the motor and stick the meter inline. I dont know what the heck you've been told about measuring separate poles but I think thats BS. Maybe also check the voltage across the line terminals of the motor while running. IME I've also found that the true rms meters give a "false" reading compared to nameplate data in this type of situation. If you have a non-rms meter kicking around maybe see what that says. If you can get the motor manufacturers name plate data thats helpful - need service factor(SF), amps(A), and service factor amps(SFA).

$500 bucks! Yikes. Got to be a cheaper alternative out there.

Steve.

I'll talk more about pump "theory" when I 've got some more time.

Jim

Dolphin Ampmasters
 

<font size="2" face="Verdana, Helvetica, sans-serif">I'll try it. I don't like opening things up that are brand new but.... ok who am I kidding. I love opening things up. :D

<font size="2" face="Verdana, Helvetica, sans-serif">SF is 1, Amps is 1.3. SFA isn't listed.

<font size="2" face="Verdana, Helvetica, sans-serif">That pushes as many GPH and even at 222W with as few watts consumed? Not even close. There are some but they can make some wicked noise that is for sure and cost even more.

Dolphin Ampmasters
 

<font size="2" face="Verdana, Helvetica, sans-serif">Cool, cuz either I am forgetting something (which it very well could be) or I was taught some bogus stuff (could be this to) :D

are you on the island? send me a e-mail maby if you are close we could get togeather for a coffee or something.

Steve

Dolphin Ampmasters
 

<font size="2" face="Verdana, Helvetica, sans-serif">Well, here we go. First I stated that *most* will trip out at 0 head and we were discussing your tub pump at the time.

Lets look at the power head first. I will give the disclaimer that I have never played with a powerhead but have other similar stuff. This is a *very* educated conjecture. First, the powerhead is operating at a very fixed/specific design point and is thus specifically built for the task (and is fairly atypical as far as centrif's go) Second, the discharge nozzle is sized to restrict the flow to certain rate (artificial head) - a flow rate that the motor is capable of handling. Should some poor misguided soul decide to tweak the powerhead a bit and drill out the nozzle (to reduce the back pressure so the pump can work easier!!!) - the flow rate will increase and overload the motor. Very certain on that.

The original start of the 0 head conversation was regarding the specs on your hot tub pump. Darren has confirmed for you my low head high amps theory. So as the head decreases, the flow increases, and the amps increase. If you look at the specs on your tub pump, at 30'/127gpm the pump will be working the hardest and drawing very close to the name plate amps. I draw this conclusion because that is where the manufacturer stops providing performance info as you stated. They dont stop publishing data because the pump will never encounter that situation (because believe me they eventually will in some application) Its because the manuf doesnt want you to f'in run it below this head. Why? Because as the head is reduced past 30', the gpm will increase, and remember our rule, the amps will increase and overload the motor. If the head is reduced further the pump will start cavitating like hell. This is not conjecture.

So now you're asking why dont they make a hot tub pump that can run down to 0 head ? Its all about design point and efficiencies. At the specific window/range of flow rate & head that your tub needs to run properly requires 1.5hp to spin the impeller. This window is usually in the pumps best efficiency range. Unfortunately that same impeller requires 2.5 hp to operate over its *entire* head range. Now do you put the extra hp on to cover a head range that shouldnt ever be encountered? Hell no. Just cut the curve off early and say dont run the pump here. That is why most centrifugals will overload at 0 or very low heads. The motor is sized to operate the pump in the effficientcy range and not over the entire head range.

With say the ampmaster and power filters they are designed to operate at 0/low heads so one wouldnt expect them to act up in this range. But dont expect all centrifugals to behave similarly as they are atypical in the wide world of pumps.

As far as the other stuff in your post the I dont quite agree with - well its not overly misinformed or misleading or dangerous and my typing totally sucks so.....

Talk to ya later.

Jim

Dolphin Ampmasters
 

<font size="2" face="Verdana, Helvetica, sans-serif">SF is 1, Amps is 1.3. SFA isn't listed.

If thats the motor spec that I dont think Dolphin is doing anything funny with their claims. This is the max amps (tested directly at the motor) and it plain cant be exceeded without the motor dropping out on overload. I dont think you are losing an amp in the power cord, it sounds like the pump is running properly (no excessive heat or kicking out), so I'd guess there's something wanky with the amp measurement. Dont know, but doesnt make sense.

Jim

Dolphin Ampmasters
 

<font size="2" face="Verdana, Helvetica, sans-serif">Jim, it has been suggested that you can cut the nozzles off powerheads to give them a little less velocity while spreading out the flow. Is this something that you see cutting the life of the pump?[/QB][/quote]

Like I said, I havent specifically played with powerheads but have done much with similar submerged pumpheads - just on a bigger scale. On those the size of the discharge nozzle is the flow restrictor that keeps the pump/motor in an acceptable operating range. Mess with it and you have troubles. Would it have the same effect on a powerhead, I can only assume that. The nozzle is there for a reason - maybe just for velocity, but velocity = pressure (back pressure on the pump, reducing flow, reducing amp draw) Hmmm, but if the powerhead (with nozzle) were not running at the absolute max rating of the motor, there might be a little bit of wiggle room when the nozzle is cut off. Wouldnt know for sure unless a person did a before & after test with a meter. If the amp draw exceeds the marked rating, it will definately affect pump life.

Jim

Dolphin Ampmasters
 

Thanks Jim.

Dolphin Ampmasters
 

<font size="2" face="Verdana, Helvetica, sans-serif">Cool, cuz either I am forgetting something (which it very well could be) or I was taught some bogus stuff (could be this to) :D

are you on the island? send me a e-mail maby if you are close we could get togeather for a coffee or something.

Steve</font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Sorry Steve but my momma told me to never ever go and see men I met on the internet........and I'm not an Islander either.

Jim

Dolphin Ampmasters
 

<font size="2" face="Verdana, Helvetica, sans-serif">Jim, it has been suggested that you can cut the nozzles off powerheads to give them a little less velocity while spreading out the flow. Is this something that you see cutting the life of the pump?