???ehiem variable speeds 120v rheostat ???

OcPunK · 02-11-2004, 08:08 PM

If I wanted to make a ehiem variable speeds could I just stick a 120v rheostat in line, or would that burn my house down and kill all the little children? Or how could I make it work like those magic hydrothunder things?

Groth · 02-11-2004, 08:58 PM

I don't know the specific of that pump, but in general AC powered pumps use synchronous motors - meaning it rotates at a set multiple of the power line's freqency. To change the speed you would need to change input frequency, not the input voltage.

AngryAlpaca · 02-11-2004, 10:01 PM

May I ask, why? I doubt slowing it would make it any quieter, and I don't really like the idea of overpowering a pump...

Meethoss · 02-12-2004, 06:22 AM

Heh - over clock your water cooling system cooling your over clocked PC :P

OcPunK · 02-12-2004, 10:13 AM

I want to test cooling at slower water speeds just for fun.

fhorst · 02-12-2004, 10:42 AM

I've attached a 220v pump to a halogeen spot trimmer, making it go from 160 to 230v.
It only started to run at 190, same noise level (even higher) , less head and my trimmer got damm hot!

To spped it up or slow it down you need to change the freqency, and those things are quite expensive. Only changing the voltage will give it less power, making it stop spinning sooner.

If you want variable, why not go for 12v pumps?

OcPunK · 02-12-2004, 10:49 AM

Are you saying with a 12v pump could I just change the voltage? What 12v pump brands are good?

prandtl · 02-12-2004, 11:43 AM

Quote:

Originally Posted by OcPunK

I want to test cooling at slower water speeds just for fun.

put a valve in your system then.

OcPunK · 02-12-2004, 11:57 AM

Wouldnt the valve just cause more pressure causing the water flow to speed up?

Butcher · 02-12-2004, 12:13 PM

More back pressure reduces flow. You'll see an increase in velocity through the value, but the flow through your block/radiator will be reduced.

Razor6 · 02-12-2004, 03:41 PM

You can do what I have done before which is hook up a fan dimmer inline with the pump. Power decreases but the speed sounds about the same. If you go too low the pump will just stop and chatter. I never did test the flow since I was just messing around so I don't know how effective it is as a flow regulator.

redleader · 02-12-2004, 04:40 PM

Read this for a detailed explination:

http://episteme.arstechnica.com/eve/...m=987000222631

(Particularly JimZ's link which explains everything from fan motors to dimmer switches)

02-11-2004, 08:08 PM	#1
OcPunK Cooling Savant Join Date: Jun 2001 Location: Under ground cave in PA to keep PCs cool! Posts: 125	???ehiem variable speeds 120v rheostat ??? If I wanted to make a ehiem variable speeds could I just stick a 120v rheostat in line, or would that burn my house down and kill all the little children? Or how could I make it work like those magic hydrothunder things? __________________ www.1337info.com

02-12-2004, 06:22 AM	#4
Meethoss Cooling Savant Join Date: Dec 2003 Location: Wales, UK Posts: 188	Heh - over clock your water cooling system cooling your over clocked PC :P __________________ Meethoss

02-12-2004, 10:13 AM	#5
OcPunK Cooling Savant Join Date: Jun 2001 Location: Under ground cave in PA to keep PCs cool! Posts: 125	I want to test cooling at slower water speeds just for fun. __________________ www.1337info.com

02-12-2004, 10:42 AM	#6
fhorst Cooling Savant Join Date: Oct 2003 Location: Almere, The Netherlands (Europe) Posts: 262	I've attached a 220v pump to a halogeen spot trimmer, making it go from 160 to 230v. It only started to run at 190, same noise level (even higher) , less head and my trimmer got damm hot! To spped it up or slow it down you need to change the freqency, and those things are quite expensive. Only changing the voltage will give it less power, making it stop spinning sooner. If you want variable, why not go for 12v pumps? __________________ If it get's hot, it needs to be watercooled!

02-12-2004, 10:49 AM	#7
OcPunK Cooling Savant Join Date: Jun 2001 Location: Under ground cave in PA to keep PCs cool! Posts: 125	Are you saying with a 12v pump could I just change the voltage? What 12v pump brands are good? __________________ www.1337info.com

02-11-2004, 08:58 PM	#2
Groth Cooling Savant Join Date: Mar 2003 Location: MO Posts: 781	I don't know the specific of that pump, but in general AC powered pumps use synchronous motors - meaning it rotates at a set multiple of the power line's freqency. To change the speed you would need to change input frequency, not the input voltage.

02-11-2004, 10:01 PM	#3
AngryAlpaca Cooling Savant Join Date: Jan 2004 Location: Alberta Posts: 631	May I ask, why? I doubt slowing it would make it any quieter, and I don't really like the idea of overpowering a pump...

02-12-2004, 11:57 AM	#9
OcPunK Cooling Savant Join Date: Jun 2001 Location: Under ground cave in PA to keep PCs cool! Posts: 125	Wouldnt the valve just cause more pressure causing the water flow to speed up? __________________ www.1337info.com

02-12-2004, 12:13 PM	#10
Butcher Thermophile Join Date: May 2001 Location: UK Posts: 1,064	More back pressure reduces flow. You'll see an increase in velocity through the value, but the flow through your block/radiator will be reduced. __________________ Once upon a time, in a land far far away...

02-12-2004, 03:41 PM	#11
Razor6 Cooling Savant Join Date: Apr 2002 Location: Houston, TX Posts: 192	You can do what I have done before which is hook up a fan dimmer inline with the pump. Power decreases but the speed sounds about the same. If you go too low the pump will just stop and chatter. I never did test the flow since I was just messing around so I don't know how effective it is as a flow regulator.

02-12-2004, 04:40 PM	#12
redleader Thermophile Join Date: Jun 2001 Location: The deserts of Tucson, Az Posts: 1,264	Read this for a detailed explination: http://episteme.arstechnica.com/eve/...m=987000222631 (Particularly JimZ's link which explains everything from fan motors to dimmer switches)

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