Fulmar Fan alternative

[veedub565]

Does anybody know where I might be able to source a suitable replacement for an IMC Fulmar fan, Model 00, 115v, 22Watt

There's a similar model here https://www.ebay.com/itm/121038022569  same style but mine is a bit bigger. It's for an HP 8341B

Not even sure what this case style is called (apart from tubeaxial) but the shape of the frame is a bit odd.

[veedub565]

Ah think I've found them now, looks like 171mm x 151mm x 51mm 6" Axial Fan. Next step to find a quiet one, 52dB seems to be the quietest so far for an RS Pro one.

[delat]

Hi! I also plan to replace this FAN. There are several models from 170CFM to 250CFM. Did you figure out flow of the original FAN?

[thm_w]

Hi! I also plan to replace this FAN. There are several models from 170CFM to 250CFM. Did you figure out flow of the original FAN?

I would just get something of similar wattage, 22W was mentioned above. I doubt its that critical.

[veedub565]

Hi! I also plan to replace this FAN. There are several models from 170CFM to 250CFM. Did you figure out flow of the original FAN?

Yes it's 180 CFM

I would just get something of similar wattage, 22W was mentioned above. I doubt its that critical.

It can be on these older HP instruments, 3335A, 8340B, 8663A etc. They rely on positive case pressure to force air around inside the unit and through small holes in the RF blocks. Static pressure of the fan is also important, the fan has got to be able to generate some pressure to force the air through.

That said, the fans were probably specced with worst case scenario in mind, running 24/7 in a tightly packed rig at 55deg (C) ambient. There probably is some leeway when fitting a replacement for light use at home.

In this case I fitted a 130 CFM fan (never did find out the static pressure spec of the OEM one) and everything seems ok so far.

[delat]

Hello. Thanks for answers! Bought this FAN https://www.mouser.com/ProductDetail/670-OA172SAP112TB Can't say it's quieter, but at least it has a new bearing and doesn't make regular weird noises. Its flow is 170 cfm, but the 22/20 watts is very close to the original. But it looks like the original was 3200 rpm. This one has 2300 rpm. The original specification states that at 60Hz-5Hz there is a residual FM equal to the FAN speed.