How to reduce flow rate?

[Crab]

Instead of using a ball valve, can a dimmer for household halogen light be used?

Reason is by using ball valve, pump continues to consume same power with lower flowrate. Whereas dimmer save on electricity as well.

Besides dimmer, will a resistor do the job?

Any advice?

[ervine]

Wah... interesting but I doubt it will work.. lights don't work the same way as pumps... in fact not all lights are dimmable in the first place...

Someone with more electircal experience care to comment on this?

[Benz...]

if what you have is a fix speed pump then no use.. you cannot slow the speed of the pump down unless you use a frequency adjuster... but no point... if you wanna reduce the flow rate then just add 90 deg elbow to your piping system..

[Glare]

if what you have is a fix speed pump then no use.. you cannot slow the speed of the pump down unless you use a frequency adjuster... but no point... if you wanna reduce the flow rate then just add 90 deg elbow to your piping system..

and that the bottom line cause pump king benz said so

[alvy]

our common pumps and powerheads and induction motor..they depend on the freq of our powersupply to run. tt's y you notice the specs of the pump usually display 2 sets of performance value. The lower performance value is for 50hz while the higher one for 60hz power supply..sad to say powergrid's running 50hz on 220v, so our pump's running slightly slower than it's full capability!

a incandescent lamp can be dimmed by a dimmer tt varies the voltage. If you apply it to an induction pump, the pump will still run on the same speed until there isn't enough voltage/current and it'll just stop right after it's minium threshold. pump can be damaged!

[Benz...]

our common pumps and powerheads and induction motor..they depend on the freq of our powersupply to run. tt's y you notice the specs of the pump usually display 2 sets of performance value. The lower performance value is for 50hz while the higher one for 60hz power supply..sad to say powergrid's running 50hz on 220v, so our pump's running slightly slower than it's full capability!

a incandescent lamp can be dimmed by a dimmer tt varies the voltage. If you apply it to an induction pump, the pump will still run on the same speed until there isn't enough voltage/current and it'll just stop right after it's minium threshold. pump can be damaged!

it can be debated whether 50/60Hz is better than one another or not... it all boils down to whether the motor is a 2 pole or a 4 pole one... not necessary that a 60hz is better.. just depends on the type of application used and for how much power flowrate and head is required... i have found that depending on the application, there are pro and cons to using the different frequency..

as to adding a dimmer switch/relay... no good... reason being that the pump need a certain amount of amp/power to start it (your startin torque).. and then since it being a fix speed pump, it will just keep wanting to draw more amp to power it... and you will wreck your pump... also while you are at it.. you will heat your electrical system up and you might cause a fire in your own home which is highly not recommended cos if the result of the fire is that you load your system too much... then insurance will not cover it...

bottom line... dont risk it... wanna flow down the pump flow, just add elbow ot make the head higher... no use even throttling your valve cos you are just adding to the pressure and head....

okie now dont read and then go okie.....

[alvy]

ok..about the pole thingy..wat is it??my pumps are single pole..wat does it means??

and does 2 poles means you can control the speed by varying voltage??

[Benz...]

it has got to do with the spec of the motor...

you can control the speed of the motor only by varing the frequency... cos is is a function of each other... then co-relating... the speed will then determine the flow and the head... whether it is 2 or 4 or 6 dont matter....

[alvy]

no, i do believe some pumps work by varying voltages rite??

[ervine]

So how to controllable streams work?

[eprouve]

So the power consumed will still be the same. 240V. Right?

[Crab]

no, i do believe some pumps work by varying voltages rite??

I used to have a 12v pump for boats, pump speed can be controlled with a variable power supply.

Is it possible to design a circuit to varies the frequencies (hz)? Logically, this circuit can be used to control pump speed right?

  So how to controllable streams work? 

Yes, anyone knows how it works?

[alvy]

i think i saw some motor controller on RS components which varies freq as well as do other functions in order not to spoil the motor..these device cost up to a few K!!!so i doubt any diy can do a workable freq controller which will not spoil the pump!

[Cookiemunster]

Guys,

DC pumps control speed by varying the voltage. Changing frequency will damage the pump.

AC pumps control speed by varying frequency. Changing voltage will damage the pump.

A three phase (double pole) pump will allow two frequency swaps, 50hz and 60hz. Hence allowing a built in speed change. I am also not very clear how this works.

[alvy]

so how does a normal fan change speed??

[Cookiemunster]

so how does a normal fan change speed??

I am still investigating. It is amazing the basic thing we often take for granted is actually so ingenius. Even the rotation is amazing. hahaha

[Hon]

I asked this question before. Those ah pek repairing electrical hardware dunno the concept behind. Those Master in Electronic student never study before. Finally I got a not so confirm answer from my aircon friend, he said fan speed is controlled by varying the frequency.

Now come the next question..

If a fan speed have 1, 2 and 3 selection, 3 being the fastest.

Is the power consumption heavier on speed 3 than on speed 1?

Nobody knows yet

[Hon]

So how to controllable streams work?

I email Tunze many times until the guy there gave up. He finally tell me that the speed of a varaible Tunze Stream pump is manupulated by frequency. In IKS product, they call its Phrase Angle control.

[Crab]

I asked this question before.  Those ah pek repairing electrical hardware dunno the concept behind.  Those Master in Electronic student never study before.  Finally I got a not so confirm answer from my aircon friend, he said fan speed is controlled by varying the frequency.

Now come the next question..

If a fan speed have 1, 2 and 3 selection, 3 being the fastest.

Is the power consumption heavier on speed 3 than on speed 1?

Nobody knows yet

If your friend is correct, maybe we can dismantle an old fan switch and fix it on pump.

[Hon]

Not all pump can be frequency manipulated hor. Will cause fire!!!

[Crab]

Not all pump can be frequency manipulated hor. Will cause fire!!!

Or

[jhansolo]

Please be careful as not all fluid pumps uses the same technology as a ceiling fan.

Burning the pump is quite a definite outcome if it is not suitable. However, the torque takes time to build up as well as the heat, you won't know when. For knowledge, get a student in electrical engineering who major in power to explain to you. My knowledge is 15 years old so a little rusty.

For practicality, get a low wattage pump with a low flowrate. You don't want Fire insurance company to find something like this in your house and take a cut from your claim.

Cheers

[Benz...]

the two most common motors out there are either the AC induction or the DC commutated shunt (or series wound). all electrical motor configurations except for the reluctance brushless type convert electrical energy to mechanical energy from the magnetic flux linkage of their two magnetic circuits. One would be the stator and the other a bearing/magnetic mounted rotor. the speed of rotation times the torque equals the output power at the motor shaft causing the shaft to rotate. This happens when the flux linkage between the two magnetic circults produces a moment of force at the rotor radius that result in a torque on the motor shaft.

basic difference between the two types of electric motors has to do with the electrical source. from would be from a power grid and the other powered by the voltage from storage batteries or from a dc generator. for ac pumps, by controlling the frequency, you would be able to control the speed of the pump and for dc.. by controling the voltage.

hope this help to clear the air....

[alvy]

this is damn cool info man!

[Crab]

After so much of technical staffs, can I confirm whether household fan switch can be used to control pump's speed?