Next week I have to go to one of my customers for measurements on their 6 new fans (belt and also frequency driven). They want to have measurements radial and axial on all the bearings of the motor and fan for each frequency (1Hz up to 50Hz). The reason for these measurements are that these installation is new and for a customer in the pharma industry. Before they build the fans in the installation, they want to know what the machine is doing on all the frequecies. They are working with a "SECTION 15919" norm (that's what they got from Lilly, the manufacturer of the fans). These measurements will be done in the shop of the vendor.
My questions now are:
* Does anyone have experince with this kind of measurements/tests
* What is the best technique to measure (transient?? regular vibration measurements??)

Cormatech
I assume you are taking these measurements to establish baseline and/or to confirm acceptablility to some established criteria?

I'm not familiar with Lilly's Section 15919 but it sounds like you should identify specifics in this forum (and for yourself).
Also, only going out to 50 Hz ??
That is very odd. You are going to miss a lot of information by limiting Fmax to 50 Hz.

If you want to discuss further, you can email me directly ivibr8@yahoo.com

Regards
Jim Powers

The 50 Hz is from the VFD, not fmax.

Definitely get Lily's spec and tailor your tests to fit.

Regards

Thanks. My bad

Jim P

Cormatech,

I have not heard of a fan manufacturer named Lilly. There is a Pharma company called Eli Lilly.

It would be a rather slow process to survey several bearing locations-directions with a single accelerometer-analyzer for each 1-Hz setting of the VFD. I have an 8-channel analyzer (ZonicBook) that would measure up to 8-accelerometers plus a tachometer to cover the entire VFD speed range in one slow VFD ramp-up cycle. I believe that the customer (whoever) is concerned about natural frequencies (resonances) that occur within the normal speed range.

Walt

Walt,

I do the same thing with the MAARS analyzer. We take it up to 60 Hz and capture the coast down. One run instead of several. Saves a lot of time.

Regards,

Cormatech,

The Lilly spec. you mentioned 15919 states two different classes of equipment (Busines critical and Business non-critical). Make sure of the type of equipment.

If it is Business critical equipment, the spec. I have seen and worked with in the past states (Equipment showing bearing fault frequencies or harmonics of FTF, BSF, BPFO and BPFI or harmonics greater than 0.01 IPS shall not be accepted). They even state maximum overall (filtered out) levels based on size of motor and foundation type.

Lilly wants a rock solid machine that will last long periods of time without breakdowns.

Good luck,
J Gorman