EHEIM pump EMI

artemis0007 · 05-22-2002, 02:21 AM

Hi all!
I was wondering how much if any EMI the EHEIM 1250 pump puts out. I have 4 HDDs that wil sit about 1", 2", 3" and 4" away respectively. Just wanted to know if there might be any magnetic fields which degrade my HDDs. Thanks!

Dix Dogfight · 05-22-2002, 03:25 AM

The 1250 has a very low EMI, so i don't think it will be a problem.

Nordic · 05-22-2002, 09:56 AM

Actually, at work we tried to kill a 10 gig drive (IBM) with a huge frickin magnet from some PA speaker. We let the magnet rest on the drive for a few days but all of the data was intact. That was a mind-blower..
So I'm not a least bit concerned about wiping data of my drives anytime soon.. the drive will have failed due to mechanical problems before that.

bigben2k · 05-22-2002, 10:41 AM

Quote:

Originally posted by Nordic
Actually, at work we tried to kill a 10 gig drive (IBM) with a huge frickin magnet from some PA speaker. We let the magnet rest on the drive for a few days but all of the data was intact. That was a mind-blower..
So I'm not a least bit concerned about wiping data of my drives anytime soon.. the drive will have failed due to mechanical problems before that.

Wow! Thanks for that great info, Nordic!

Magnets themselves have a magnetic field, but don't actually generate EMI field, but a MOVING magnet does! In the test above, the disk drive platter was spinning at at least 5400 rpm (right Nordic?) which has the same result.

EMI comes from just about any AC powered device, simply because the voltage changes from 0 to +170V to 0 to -170V (hence 120 Vac, which is RMS, with a peak at 170V) in a nice sine wave.

Nordic · 05-22-2002, 11:06 AM

Actually static magnets (fields) are the most disruptive for magnetically stored media, so we didn't have the disk plugged in - the magnet and disk were "not moving". Actually the data stored on disk is less prone to damage when it's running because of the reason you mentioned!
EMI might disrupt data communication between disk and motherboard but you need the correct amplitude and frequency to cause transmission errors.

Heh, I better talk to the electrical engineer at work who got the idea, in case my claims aren't correct.

artemis0007 · 05-22-2002, 12:07 PM

Sooo... whatever magnetic field is produced by the pump will not corrupt data or send the head crashing into the platter. Sounds good. Thanks!

bigben2k · 05-22-2002, 12:58 PM

Quote:

Originally posted by Nordic
Actually static magnets (fields) are the most disruptive for magnetically stored media, so we didn't have the disk plugged in - the magnet and disk were "not moving".

Heh, I better talk to the electrical engineer at work who got the idea, in case my claims aren't correct.

Check with him...

Fixed magnets are bad for magnetically stored media, because the movement of the magnet towards the media creates an increase in magnetic field strength (from the tape/HD point of view) which is a varying magnetic field, aka EMI. Keep them at a fair distance, and everything is fine, but rev up the HD platter to 5400 rpm, and wait...

Try the HD thing again, but power it up, not connected to a PC. I can guarantee you that you will never see a HD so messed up

Nordic · 05-22-2002, 02:43 PM

The explanation I got was:
A professional degausser/eraser works with fluctuating magnetic fields but the purpose of that is to totally randomize the data. The effect of applying a static magnetic field is that you would be able to distinguish recorded data easier as some parts of the media were probably already aligned with the tape but the parts that weren't will still differ slightly (less and less the stronger the field).

(translated to english from swedish)

bigben2k · 05-22-2002, 02:50 PM

Actually, I've tried an AC degausser/demagnetizer on floppy disks: it's just a big coil. Surprisingly, some floppies actually came out intact! (Thanks Radio-Scrap!)

Again though, because the voltage changes (AC), it creates a varying magnetic field. The variation in magnetic field can be translated in some unit of measure (I don't remember which, that part of physics was a long time ago!). A fixed magnet's field doesn't move, unless you move the magnet, or move the object near/around the magnet...

c'mon... won't you try to trash that HD for us? In the interest of science...

Nordic · 05-22-2002, 02:57 PM

But with regards to watercooling and pumps, there is absolutely no problem with having an aquarium pump inside your computer. They are shielded to begin with (all EHEIMs are), and so are hard drives. An immense magnetic field is required to erase even a floppy disk and my engineering friend assures me that I have nothing to worry about. He said something about the non-existance of a device that could completely wipe a modern hard-drive, that sounds wicked!

As a test I put my pump in front of my monitor and noticed only slight discoloration when the pump housing was a couple of centimeters from the glass, even the smallest loudspeaker has a stronger field than that.

Nordic · 05-22-2002, 02:58 PM

I will try to find that drive again, it's on a shelf somewhere in storage. In the name of science, yeah

bigben2k · 05-22-2002, 03:05 PM

Yep, right on! We really don't have to worry about EMI from a pump inside a case. (Shielded or not, if you ask me).

Monitors though are sensitive to fixed magnets (and EMI too!), because the point of color is actually an electron beam hitting the screen, and it is directed by magnetic deflection (hence the big coils behing the tube). So a magnet will make a monitor/tv do weird things...

Not to say that they'll break or anything: they'll just discolor, temporarily. Monitors usually degauss themselves on startup now (wasn't like that 10 years ago). TVs though, don't usually have a degauss circuit...

redleader · 05-22-2002, 07:37 PM

I sat my 1250 next to my TV. No effect, while even a speaker distorted it.

Cyco-Dude · 05-23-2002, 02:14 AM

yeah, but was the pump on??

Nordic · 05-23-2002, 11:49 AM

Yes, of course my pump was running. Don't know about redleader's..

Cyco-Dude · 05-23-2002, 01:40 PM

yeah, i was talking about redleader's

Marco · 05-25-2002, 09:38 PM

Magnetic fields units-> Tesla i believe.

Divided · 05-25-2002, 11:08 PM

tesla coils are sick

Gnozo · 05-26-2002, 01:01 AM

My Eheim 1048 isn't shielded too well, if I move set i too close to my monitor, then it starts flickering, it has to be atleast 60cm's away from it

Nordic · 05-26-2002, 07:20 AM

WoW! That's not my experience at all, I had to bring it up real close to the monitor to experience color perturbation. Of course your monitor might not be as well shielded as my Trinitron, but in any case I wouldn't worry. Electron guns are very sensitive to magnetic fields as you can imagine and can't be compared to magnetic media.

05-22-2002, 02:21 AM	#1
artemis0007 Cooling Savant Join Date: Sep 2001 Location: Davis, CA USA Posts: 113	EHEIM pump EMI Hi all! I was wondering how much if any EMI the EHEIM 1250 pump puts out. I have 4 HDDs that wil sit about 1", 2", 3" and 4" away respectively. Just wanted to know if there might be any magnetic fields which degrade my HDDs. Thanks!

05-22-2002, 03:25 AM	#2
Dix Dogfight Cooling Savant Join Date: Aug 2001 Location: Stockholm Sweden Posts: 128	The 1250 has a very low EMI, so i don't think it will be a problem. __________________ If it ain't broke, fix it. Setup: Dual Duron 1100 \| Voodoo 3 2000 \| Addtronics W8500(WTX) \| Eheim 1250 \| Car radiator \| 2 Innovatech WB \|

05-22-2002, 09:56 AM	#3
Nordic Cooling Neophyte Join Date: Mar 2001 Location: Umeå, Sweden Posts: 98	Actually, at work we tried to kill a 10 gig drive (IBM) with a huge frickin magnet from some PA speaker. We let the magnet rest on the drive for a few days but all of the data was intact. That was a mind-blower.. So I'm not a least bit concerned about wiping data of my drives anytime soon.. the drive will have failed due to mechanical problems before that. __________________ Pump:Eheim 1048, Radiator:LPD radiator 100x150x20mm, CPU block:DD Maze-2, GPU block: DD GPU block, Chipset block:Zalman NB32 AMD XP 1500+, EpoX 8K7A, PoV GF3Ti200 Pic of my YY-cube

05-22-2002, 11:06 AM	#5
Nordic Cooling Neophyte Join Date: Mar 2001 Location: Umeå, Sweden Posts: 98	Actually static magnets (fields) are the most disruptive for magnetically stored media, so we didn't have the disk plugged in - the magnet and disk were "not moving". Actually the data stored on disk is less prone to damage when it's running because of the reason you mentioned! EMI might disrupt data communication between disk and motherboard but you need the correct amplitude and frequency to cause transmission errors. Heh, I better talk to the electrical engineer at work who got the idea, in case my claims aren't correct. __________________ Pump:Eheim 1048, Radiator:LPD radiator 100x150x20mm, CPU block:DD Maze-2, GPU block: DD GPU block, Chipset block:Zalman NB32 AMD XP 1500+, EpoX 8K7A, PoV GF3Ti200 Pic of my YY-cube

05-22-2002, 02:43 PM	#8
Nordic Cooling Neophyte Join Date: Mar 2001 Location: Umeå, Sweden Posts: 98	The explanation I got was: A professional degausser/eraser works with fluctuating magnetic fields but the purpose of that is to totally randomize the data. The effect of applying a static magnetic field is that you would be able to distinguish recorded data easier as some parts of the media were probably already aligned with the tape but the parts that weren't will still differ slightly (less and less the stronger the field). (translated to english from swedish) __________________ Pump:Eheim 1048, Radiator:LPD radiator 100x150x20mm, CPU block:DD Maze-2, GPU block: DD GPU block, Chipset block:Zalman NB32 AMD XP 1500+, EpoX 8K7A, PoV GF3Ti200 Pic of my YY-cube

05-22-2002, 12:07 PM	#6
artemis0007 Cooling Savant Join Date: Sep 2001 Location: Davis, CA USA Posts: 113	Sooo... whatever magnetic field is produced by the pump will not corrupt data or send the head crashing into the platter. Sounds good. Thanks!

05-22-2002, 02:50 PM	#9
bigben2k Responsible for 2% of all the posts here. Join Date: May 2002 Location: Texas, U.S.A. Posts: 8,302	Actually, I've tried an AC degausser/demagnetizer on floppy disks: it's just a big coil. Surprisingly, some floppies actually came out intact! (Thanks Radio-Scrap!) Again though, because the voltage changes (AC), it creates a varying magnetic field. The variation in magnetic field can be translated in some unit of measure (I don't remember which, that part of physics was a long time ago!). A fixed magnet's field doesn't move, unless you move the magnet, or move the object near/around the magnet... c'mon... won't you try to trash that HD for us? In the interest of science... __________________ WBTA (Water Block Testing Alliance) Nordic Hardware WC 101

05-22-2002, 02:57 PM	#10
Nordic Cooling Neophyte Join Date: Mar 2001 Location: Umeå, Sweden Posts: 98	But with regards to watercooling and pumps, there is absolutely no problem with having an aquarium pump inside your computer. They are shielded to begin with (all EHEIMs are), and so are hard drives. An immense magnetic field is required to erase even a floppy disk and my engineering friend assures me that I have nothing to worry about. He said something about the non-existance of a device that could completely wipe a modern hard-drive, that sounds wicked! As a test I put my pump in front of my monitor and noticed only slight discoloration when the pump housing was a couple of centimeters from the glass, even the smallest loudspeaker has a stronger field than that. __________________ Pump:Eheim 1048, Radiator:LPD radiator 100x150x20mm, CPU block:DD Maze-2, GPU block: DD GPU block, Chipset block:Zalman NB32 AMD XP 1500+, EpoX 8K7A, PoV GF3Ti200 Pic of my YY-cube

05-22-2002, 02:58 PM	#11
Nordic Cooling Neophyte Join Date: Mar 2001 Location: Umeå, Sweden Posts: 98	I will try to find that drive again, it's on a shelf somewhere in storage. In the name of science, yeah __________________ Pump:Eheim 1048, Radiator:LPD radiator 100x150x20mm, CPU block:DD Maze-2, GPU block: DD GPU block, Chipset block:Zalman NB32 AMD XP 1500+, EpoX 8K7A, PoV GF3Ti200 Pic of my YY-cube

05-22-2002, 03:05 PM	#12
bigben2k Responsible for 2% of all the posts here. Join Date: May 2002 Location: Texas, U.S.A. Posts: 8,302	Yep, right on! We really don't have to worry about EMI from a pump inside a case. (Shielded or not, if you ask me). Monitors though are sensitive to fixed magnets (and EMI too!), because the point of color is actually an electron beam hitting the screen, and it is directed by magnetic deflection (hence the big coils behing the tube). So a magnet will make a monitor/tv do weird things... Not to say that they'll break or anything: they'll just discolor, temporarily. Monitors usually degauss themselves on startup now (wasn't like that 10 years ago). TVs though, don't usually have a degauss circuit... __________________ WBTA (Water Block Testing Alliance) Nordic Hardware WC 101

05-22-2002, 07:37 PM	#13
redleader Thermophile Join Date: Jun 2001 Location: The deserts of Tucson, Az Posts: 1,264	I sat my 1250 next to my TV. No effect, while even a speaker distorted it.

05-23-2002, 02:14 AM	#14
Cyco-Dude Cooling Savant Join Date: Feb 2002 Location: Dayton, Ohio Posts: 836	yeah, but was the pump on??

05-23-2002, 11:49 AM	#15
Nordic Cooling Neophyte Join Date: Mar 2001 Location: Umeå, Sweden Posts: 98	Yes, of course my pump was running. Don't know about redleader's.. __________________ Pump:Eheim 1048, Radiator:LPD radiator 100x150x20mm, CPU block:DD Maze-2, GPU block: DD GPU block, Chipset block:Zalman NB32 AMD XP 1500+, EpoX 8K7A, PoV GF3Ti200 Pic of my YY-cube

05-23-2002, 01:40 PM	#16
Cyco-Dude Cooling Savant Join Date: Feb 2002 Location: Dayton, Ohio Posts: 836	yeah, i was talking about redleader's

05-25-2002, 09:38 PM	#17
Marco Cooling Neophyte Join Date: Mar 2002 Posts: 79	Magnetic fields units-> Tesla i believe.

05-25-2002, 11:08 PM	#18
Divided Cooling Neophyte Join Date: May 2002 Location: NY, USA Posts: 81	tesla coils are sick __________________ Pentium IV 1.8A NW @ 2.65Ghz Alpha Heatsink w/ Panaflo H1A ASUS P4S533 Mobo 512Mb Mushkin Level2 DDR-SDRAM VisonTek GeForce3 Ti500 (254/540Mhz) 2 x 60Gig Seagate HD's W.D. Caviar 8Mb Buffer - 80Gig HD HighPoint Rocket404 Raid Controller Plextor 40/12/40A CD-RW

05-26-2002, 01:01 AM	#19
Gnozo Cooling Savant Join Date: Apr 2002 Location: Denmark Posts: 105	My Eheim 1048 isn't shielded too well, if I move set i too close to my monitor, then it starts flickering, it has to be atleast 60cm's away from it __________________ AMD XP1700+ @ JIUHB 12 x 202 Epox 8RDA+ Samsung PC2700 512mb Asus V8420 TI4200 Eheim 1048 - Maze1 - AirPlex EVO240 - Lian Li PC-61

05-26-2002, 07:20 AM	#20
Nordic Cooling Neophyte Join Date: Mar 2001 Location: Umeå, Sweden Posts: 98	WoW! That's not my experience at all, I had to bring it up real close to the monitor to experience color perturbation. Of course your monitor might not be as well shielded as my Trinitron, but in any case I wouldn't worry. Electron guns are very sensitive to magnetic fields as you can imagine and can't be compared to magnetic media. __________________ Pump:Eheim 1048, Radiator:LPD radiator 100x150x20mm, CPU block:DD Maze-2, GPU block: DD GPU block, Chipset block:Zalman NB32 AMD XP 1500+, EpoX 8K7A, PoV GF3Ti200 Pic of my YY-cube

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