VFD Harmonic Filter over-temperature or fan failure?

[Shark96]

We have Allen Bradley Power Flex 750 series VFDs installed at our plant for Cooling tower fan motors. Harmonic filters are also installed Schaffner passive filter fn3410-320-99. However indication for fan failure (or over-temperature) keep appearing on the filter indication controller card. The motors are run upto 54 hz and are designed to go up to 60 hz. Any suggestions for permenant solution for fan failure?

 

[jraef]

Better fans?

You need to do a little more work on your own here. Fans can fail for more reasons than we have space for in this forum. Did you try calling your Schaffner dealer or whomever supplied the filter? Did you look at the location of the air intakes for the harmonic filter to make sure it is not sucking in hot air off of the VFD heat sinks to try to keep the filter cool? That's one mistake I see happen sometimes.


"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington

 

[lukin1977]

Are the fans failing or not?

 

[Skogsgurra]

What make are the fans?

I have had remarkable things happening with fans where the manufacturer insisted on filters between VFD and fan.

And then more natural things like overheating because of voltage drop in the filter. The latter van usually be handled by increasing the V/Hz ratio in the VFD to avoid excessive slip.

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[Marke]

Hello Shark96

Passive harmonic filters typically dissipate as much power as the drive they are correcting.
If you enclose the harmonic filter in an enclosure, you need to ensure that there is sufficient airflow through the enclosure to limit the temperature rise within the enclosure. If you are not careful, the internal fan will just circulate and heat the air within the enclosure.


Mark Empson
Advanced Motor Control Ltd

 

[Shark96]

@lukin 1977 Fan themselves are fine. However some supply modules of fans have failed. When we commissioned the harmonic filters almost a year back, we were given the impression they were trouble free. I think it is too soon for the modules failure.

 

[singapore11singapore]

Hi,
I recently had some Schneider drives running some fans with a Schaffner filter also continuously give a temp alarm...even when I heat gun the units it is clear that the temp is fine. Think there is an issue with the firmware on the Schaffner units

 

[Shark96]

Guys I ordered new HF controller module as well as fan supply module from Schaffner. However, the parts I received do not look the same to me. The part numbers were different from what we ordered so i rejected the modules. Then the supplier gave guarantee that the parts were same with different numbers. I have attached pictures of existing modules and the new ones. Any suggestions would be helpful as I am confused. The fan module card is physically bigger and has a different mounting orientation The controller module card has different number of jacks.

 

[jraef]

Most people will not open .rar files as they can contain worms and other nasty things.

It might be that they know that fan had a problem and the different looking parts are the fix. But if there is no way to connect them, maybe you just got hold of an idiot at the factory...


"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington

 

[Shark96]

jraef,
Thanks for helping. Please see the pictures now. What do you think?

Existing controller module

New controller module

Existing Fan supply module

New fan supply module