Low noise fan replacement for EBM W2S107-AA15-16 115V~ (Datron/Wavetek 4808)?

[Samogon]

Lowest i can find on Digikey with relatively close CFM is 46dBA.
There is direct dependency of noise and CFM you cant trick nature in the same package size. I allow 10% max for blades shape, but not in magnitudes.

[quarks]

Just meassured 2600 RPM at 230V, so the data is unfortunately wrong and that is unaceptable.
Now I question also the 32dB(A), but still I remember the fans I replaced were significantly louder.

[carl_lab]

Does anybody know how to measure noise level (distance, angle, environment etc.)?
Maybe I can borrow a noise level meter.

[HighVoltage]

I use an iPhone app these days. Probably not so accurate but also not so bad for just comparison purpose.

[Samogon]

Just meassured 2600 RPM at 230V, so the data is unfortunately wrong and that is unaceptable.
Now I question also the 32dB(A), but still I remember the fans I replaced were significantly louder.

Ok so i can order 46 dBA

[alm]

Does anybody know how to measure noise level (distance, angle, environment etc.)?
Maybe I can borrow a noise level meter.

For an accurate measurement you should be measuring at a decent distance (1m is the standard I think). That makes it tricky to measure low speed (noise) fans without special equipment. Ideal environment is an anechoic chamber. Look at what these guys have done.

I do not think that angle is particularly critical at that distance. Ideal is probably something like 30-45° off axis. This document contains some relevant information.

[Armadillo]

Wonder why you guys are even bothered with unqualified noise figure of unqualified flow at free air delivery especially when the installation is not going to be free air delivery?
I can brochure a page saying 1 dbA at 1800 CHM but if upon questioning I tell you that I measured it 100m away, OK.   

Even if the figures of noise at FAD are sworn to be in compliance to certain international standards of compliance in testing, I don't find it of any use here unless you going to free blow the small little fan.

Cheers!

[alm]

Because the manufacturer is not likely to have measured the noise of their fan in a Datron 4808, so free air is the only figure you have in the datasheet? How else would you compare fans without buying multiple and testing yourself?

[Armadillo]

Because the manufacturer is not likely to have measured the noise of their fan in a Datron 4808, so free air is the only figure you have in the datasheet? How else would you compare fans without buying multiple and testing yourself?

Well, Datron did and also considered the pressure losses and induced noises amongst other engineering aspect in their selection.
But admittedly, new discovery is also a good contribution to the community and thanks for the efforts to be contemporary over the instrument manufacturer.
Do share your discoveries.     

[carl_lab]

Then I think we can assume the Conrad specs are wrong (I trust a manufacturer's datasheet over what Conrad claims).

Finally I got the requested datasheet from Conrad and Voelkner:

[Samogon]

That is more realistic parameters
Last night i have installed
www.digikey.com/product-detail/en/UF12A12-BTLR/1570-1015-ND
It is bit quieter will measure temperature inside unit

Well it is much quieter:
With original fan i had 90 dB(A)
With new 62 dB(A)
Definitely airflow twice lower, will monitor temperature if it is sufficint and DATRON engineers were really cautious

[Samogon]

After 30 minutes run with 100VDC output enabled i have 35C in the heatsinks
With ambient temperature 23.5C
Intake 24C
Exhaust 32C

[carl_lab]

Can you post some photo where your temp sensor was located?

[Samogon]

Plunged right into fins of heatsink.

[carl_lab]

Plunged right into fins of heatsink.

I wasn't fearless enough to do so ("DANGER High Voltage" sticker on the beige plastic shield), so I placed it between heatsink of HV block and connectors of the first daughter board:


Picture shows only location (montage of your pic).

Using original fan I measured 33°C after a few hours at ambient temperature of 23°C.

I'll order the fans from Conrad/Voelkner next week.

BTW: what's the 50V/400V switch for?

[Samogon]

Great news! So we are only 2-3 degree apart. I think we should be good.
50/400 swith enables high voltage option, so user cant go higher than 100Volts if remember correctly.

[carl_lab]

I was just wondering about the 400V notation because calibrator spits out 1000VDC.