When I balance an overhung fan with 6 blades I use the vector split (using data pac 1500) When I turn on the static/couple the vector split turns off If I need to add a weight to blades 2 & 3 on couple side Do I put the same weight 180* across on static side #2 blade on #5 blade and #3 blade on #6 blade?

Balance the overhung rotor in the "static" mode first. The bearing next to the fan wheel should be balanced down as far as possible using the "plane" of the fan wheel next to fan bearing. Once you have done this then you should check the bearing next to the pulley/coupling. If it is still showing high 1x, (truly imbalance) then you will need to balance in a "couple" mode. You will not touch the weights you used to balance the static out. You now use 2 weights that weigh the same. One will be placed on suction side of fan and the other in the "static" correction plane, but they must be 180 degrees apart.
Hope this helps
Dave

Gary, as I understand you are balancing a fan - blade type and not a squirrill cage; correct?

Your calculation called for a weight between blades 2 & 3, so you want to split the weight to blades 2 & 3 - is this correct?

If so: On a polor plot paper; draw your fan to scale and put your angle wgt radius at the angle between blades 2 & 3; you can now transfer from the calculated angle to a point on the blades intersection the blade at 90 degrees. Scaling will give proper wgt to put on each blade.

Also, check www.vibronurse.com

Look at the F1 key I think. Can't you just turn vector split back on? I think I have before, and then said "whew" when I saw the split for a couple weight. More than I wanted to do.
I'm pretty sure you can turn it back on.

Dave

A variation of Dave's procedure, is that after you balance using data at the fan-end bearing, you switch to the sheave-end bearing, and balance the sheave. This is easily done using a 2-part steel putty. Often, when a sheave is replaced, the wrong key is installed (too short or too long) and I find it easier to just balance it than replace the key (notice the putty is opposite the short key in the picture below). Balancing the sheave will have little if any effect on the fan balance done at the fan-end bearing.

On overhung fans, we often forget there are actually 2 rotors, the fan and the sheave.