Fluke 5440B Fan replacement

[e61_phil]

Hi,

my Fluke 5440B is extremly loud. Therefore, I would like to replace the fan by a new one. Does anyone know a good (perhaps silent) replacement which is available in germany (115VAC isn't usual here)?

Does anyone know something about the original specification of the fan? (m³/h and so on..)

Thanks
Philipp

[Dr. Frank]

Google is your friend: Part B1 => WR2A1 - 027117 => http://mediaserver.voxtechnologies.com/FileCache/Comair%20Rotron=027117=datasheet1-781007576.pdf

ebmPabst usually have all kind of 115VAC fans on stock, and there's still a direct sale item on their site:
http://www.ebmpapst.com/de/contact/express_service_center_d/express_service_center_D_1.html

That I've used years ago for a new fan for my HP5370B.

Pabst type 4800 N might fit.

Frank

[e61_phil]

Thanks Dr. Frank!

I ordered an EBM Papst 4800N. I hope it will fit

Edit: Oh, I saw your edit only now. I'm glad I've choosen the same one.

[e61_phil]

The EBM Papst 4800N arrived today. It fits perfectly and I measured 54dB before and 46dB after the fan replacement (0,5m away measured with a simple smartphone app...)

[leighcorrigall]

Hi e61_phil,

My 5440B is also experiencing a fan issue. The volumetric flow rate seems too low which is likely causing a power supply fault because it is too hot.

Did the EBM Papst 4800N fit on the bracket? Do you think the flow rate is suitable now that you have had more experience with the fan upgrade?

EDIT: Also, does the fan have a power connector? It sort of looked like it, but I was unable to unplug it last time the case was open. Otherwise, what is the best approach to desoldering the leads from the main board located on the base of the unit?

Since the 4800N seems to be obsolete now, what about using a 4606ZW instead? It has a flow rate of 3 m^3/min at 45 dB with a consumption of 18 W.

Thank you.

[martinr33]

You should check the p/v curves for the fan. Ideally, they should match the originals. A couple of things to look at:

 - Power consumption goes up with the cube of the speed.
 - A fan can be optimized for high speed, or high oressure (at the extremes).

Some fan designs are smarter now, and waste less energy in noise and turbulence. Not all.

[leighcorrigall]

For those looking for the original specifications:

Manufacturer: Rotron
Part number: WR2A1
Rotron Series: Whisper
Fan Type: Axial AC Fan
Size: 120 x 120 x 38 mm
Voltage: 115 VAC
Power: 7 W
Speed: 1660 RPM
Flow: 56.0 CFM (1.59 m³/min)
Bearing: Sleeve
Shape: Square
Static Pressure: 0.070 in H2O (17.5 Pa)
Noise: 33.9 dBA

[leighcorrigall]

I installed a new AC fan moments ago. The process was simple because the Fluke 5440B has a plug that fits the AC fan terminals. There is no need to tear the entire instrument apart for this job. 

Manufacturer: ebm-papst
Part number: 4530Z
Rotron Series: 4000Z
Fan Type: Axial AC Fan
Size: 120 x 120 x 38 mm
Voltage: 115 VAC (60 Hz)
Power: 12 W
Speed: 2000 RPM
Flow: 70.6 CFM (2 m³/min)
Bearing: Sintec
Shape: Square
Static Pressure: 0.070 in H2O (17.5 Pa)
Noise: 32 dBA

Instructions [maximum of 20 minutes to perform]:

1) De-energize the unit, remove the cover (5 screws), use a digital multimeter to drain both rear capacitors by setting the meter to >= 1000 DCV and measuring zero volts. Note: This is a precautionary step. No charge should exist after the unit has been unplugged.
2) Remove the fan filter (optional, 4 screws), the 2 nuts on the AC fan at the top, then remove the fan by pulling it forward from the top. Tips: If you apply a little force downwards, it comes off without wearing out the threaded posts. There is no need to remove the unguarded power supply or capacitors for this step.
3) Disconnect the AC fan plug either before removing the fan or afterwards, depending on the accessibility of the plug.
4) Replace the AC fan with one that is equal or greater to the original performance (posted shown above). Warning: When selecting a fan, do not use a fan with significant performance advantages than the original or the ovenized reference boards may over-compensate for the internal temperature change.
5) Reassemble the parts in the reverse order.

Comments:

- There was a gap (i.e., 1 - 2 mm) between the new fan and the chassis wall at the bottom. Perhaps the fan geometry needs to be more like the Rotron Whisper (WR2A1) to sit properly on the tab. I did try to push it closer, but the fan eventually slipped back to where it was. The gap should not make a significant difference on performance and maybe this is what it does with the original fan too -- I did not check.

- Over the next few days, I plan on testing whether or not the instrument can continuously source voltage on the 22 V range. Hopefully, this fan update prevents the 'power supply fault, check unguarded power supply' error message that my unit has been experiencing. The problem occurred even after I reapplied thermal paste to most of the critical components, replaced all the capacitors and carbon composite resistors, and adjusted the trimmers on the guarded power supply.

[leighcorrigall]

...

Over the next few days, I plan on testing whether or not the instrument can continuously source voltage on the 22 V range. Hopefully, this fan update prevents the 'power supply fault, check unguarded power supply' error message that my unit has been experiencing.

...

So far so good. The fan is as quiet as the original with the added benefit of additional flow rate. I created a differential voltmeter based on Figure 2-4 of the Fluke 752A instruction manual. The calibrator is stable at 23.4 °C, although there is a difference of approximately 8 to 9 μV between the 732A and the 5440B. This difference was not apparent prior to installation. My guess is that an internal calibration must be performed on the 5440B now that a new fan has been installed. I will leave the instrument to roast overnight to determine if the power supply fault reappears.

[leighcorrigall]

...

Over the next few days, I plan on testing whether or not the instrument can continuously source voltage on the 22 V range. Hopefully, this fan update prevents the 'power supply fault, check unguarded power supply' error message that my unit has been experiencing.

...

So far so good. The fan is as quiet as the original with the added benefit of additional flow rate. I created a differential voltmeter based on Figure 2-4 of the Fluke 752A instruction manual. The calibrator is stable at 23.4 °C, although there is a difference of approximately 8 to 9 μV between the 732A and the 5440B. This difference was not apparent prior to installation. My guess is that an internal calibration must be performed on the 5440B now that a new fan has been installed. I will leave the instrument to roast overnight to determine if the power supply fault reappears.

The Fluke 5440B has experienced no more power supply faults (i.e., 'check unguarded power supply') since it began continuous operation. If the fan is replaced, an external calibration should be performed because the internal temperatures will offset the internal references which do not seem to be corrected with an internal calibration.

The ebm-papst 4530Z is suitable for the 5440B thermal management. It could be advantageous to purchase a fan with slightly higher performance measures, however, it is likely that the noise factor will increase considerably as a consequence. A higher fan performance will also consume more power directly and perhaps indirectly by forcing the internal ovens to overcompensate.

 

[leighcorrigall]

...

Over the next few days, I plan on testing whether or not the instrument can continuously source voltage on the 22 V range. Hopefully, this fan update prevents the 'power supply fault, check unguarded power supply' error message that my unit has been experiencing.

...

So far so good. The fan is as quiet as the original with the added benefit of additional flow rate. I created a differential voltmeter based on Figure 2-4 of the Fluke 752A instruction manual. The calibrator is stable at 23.4 °C, although there is a difference of approximately 8 to 9 μV between the 732A and the 5440B. This difference was not apparent prior to installation. My guess is that an internal calibration must be performed on the 5440B now that a new fan has been installed. I will leave the instrument to roast overnight to determine if the power supply fault reappears.

The Fluke 5440B has experienced no more power supply faults (i.e., 'check unguarded power supply') since it began continuous operation. If the fan is replaced, an external calibration should be performed because the internal temperatures will offset the internal references which do not seem to be corrected with an internal calibration.

The ebm-papst 4530Z is suitable for the 5440B thermal management. It could be advantageous to purchase a fan with slightly higher performance measures, however, it is likely that the noise factor will increase considerably as a consequence. A higher fan performance will also consume more power directly and perhaps indirectly by forcing the internal ovens to overcompensate.

 

I hunted down some additional overheating problems which were the FILTER and OUTPUT boards. My conclusion is to make sure to reapply thermal paste to ALL components mounted to heat sinks.

Since the exhaust temperature for the Fluke 5440B was still 36 °C when the ambient temperature was 23 °C (i.e., ΔT_max = 13 °C) after a 4530Z fan replacement, I decided that it might be a good idea to try another fan...

This time, I used a 4600Z from the same company as before. The noise is loud, but it works. The exhaust temperature is now 27 °C for an ambient temperature of 19 °C and 31 °C for an ambient temperature of 23 °C (i.e., ΔT_max = 8 °C).

Manufacturer: ebm-papst
Part number: 4600Z
Rotron Series: 4000Z
Fan Type: Axial AC Fan
Size: 120 x 120 x 38 mm
Voltage: 115 VAC (60 Hz)
Power: 18 W
Speed: 3100 RPM
Flow: 106 CFM (3 m³/min)
Bearing: Ball, Sleeve
Shape: Square
Static Pressure: 0.080 in H2O (18 Pa)
Noise: 45 dBA

Final Recommendations:
A) If you have good temperature control over your workspace and do not want noise, use the 4530Z. I would think that the specified noise matches the actual performance.
B) Otherwise, use the 4600Z. I measured the noise at 1.8 m (6 ft) to be 44 dB with a Google Play App. It may consume more power directly because of the fan, but also the ovens may need to compensate for a cooler chassis. Perhaps a cooler chassis may improve the lifespan of the unit.