i am new join tranee in jindal steel and power limited.i want to know procedure of static balancing of fan.

The nomenclature incorporating "Static" is a little bit messed up. In my world static balancing include putting the object on a "perfect straight shaft" on 2 edges and balance until it it´s even and not turning. In my view a useless procedure part from a very limited number of cases. In some environments however Static balancing is in fact a 1-plane vector balancing. I hope you are doing that. In that case you need a tool that give you vector readings and today normally you have software that to the fiddly bits. You need data from a reference run, a test run with known testweight and position and like magic you get a calculated weight and once in a while it is good after that, normally you need some trim runs. If you specify what tool you have it´s easier to guide more specific. Good luck, balancing is fun when it works! Olov

please give me procedure of static balancing of fan wihtout use of any instrument.

I presume this in NOT a high speed fan!
Put fan/shaft assembly on two "knife edge" rollers and make sure it is perfectly level.
Give the fan i slight turn and let it come to rest.
Repaet the turn/rest and note where the fan stops. It will ALWAYS stop with its HEAVY SIDE DOWN.
Add a small amount of weight (plasticine) OPPOSIT the heavy spot.
Repeat the slight turns. Note again where the heavy side is and correct as before.
Your aim is to get the fan to stop "randomly", not always in the same position.
Once you achieve this, replace the added weight with a permanent one (small bolt, weld etc) and then REPEAT the turn/stop check.

I'm like Oli regarding static; maybe due to my age! But a rotor in the shop should be check in this manner first generally. Move to balancing machine and simple balance requires 1 plane. Dimensionally the rotor may require a 2 plane balance. A static fan rotor in situ; if you have the belts off and the rotor freely turns and a heavy spot swings to the bottom you may attach a weight to allow the rotor to stop at any random location and then perform instrument balancing.

Many offer training courses and there are books. Also helpful would be a lab rotor kit for practice but don't re-invent the wheel (no, I didn't get this from the caveman), do it per prescribed proven methods according to Hoyle.

It's Friday ya-te-da!!!!!!!!!

The in situ static balancing that Sam describes, I have found to be a necessity rather than a want to at times due to the severity of unbalance. Using an older IRD 880, I have seen the analog meter peg out at 100 mils. Needless to say this in one of the cases where static balancing was a requirement. I know of another case where the application was vertical and the procedure was to static balance then install and have it dynamically balanced. On one occasion they chose not to static balance and had to disassemble the unit and start over. Vertical applications have no heavy spot to fall to.
Of course balancing in a machine is the preferred method but the static methods mentioned above by Cheddar and Sam have worked for me in a number of cases where I had no other choice.

Ronnie

I have used this procedure for severe unbalance. Assuming the rotor shaft is horizontal and it can rotate freely in its bearings:

1) Mark the bottom of the rotor with chalk, since this should be the heavy spot.
2) Rotate the rotor 90-degrees so unbalance weight has greatest force (gravity) and confirm that heavy spot falls back to the bottom (6:00 clock position).
3) Bring rotor heavy spot back to 90-degees (say 3:00 clock position)
4) Now add weight to opposite side from the heavy spot (say 9:00 clock position) until rotor no longer wants to rotate in either direction.
5) Now convert the trial amount of weight into a usefull spinning weight (attached to backing plate or shroud) by maintaining the same mass x radius (say oz-in or kg-cm)
5) Now run the fan and use instruments to improve the balance as needed.

If you don't have any instruments, then place a coin on edge on the bearing housing and see if it stays upright.

Now lets see if anyone accuses me of being a rocket scientist!

Walt

please give me detailed procedure of alingment of shaft by dial gauge.

There is a lot of info availible on the web u can google it yourself

how to decide trial weight for dyanamic balancing of rotor.

how to identyfy the sound in bearing by vibration signature analysis.

Neeraj - you say you are a "trainee" at the plant. Who is your "mentor"? Presumably, as a trainee, you are there to learn from a senior or other persons who have been there some time and knows the answers. This being the case, why can't/don't you ask them all this basic stuff???

Walt,

I used a very similar method to balance a fan that I couldn't run, but had to run continuously after it started.

Got it to 3 mils at about 900 rpm. Good enough to run for the 3 weeks required.

how to decide the thickness of shim,adding and removing of shim in offset and angular alignment of shaft.

My friend,

You are extremely irritating with your questions. If you have no idea about vibration analysis, alignment or balancing; please purchase some good books or take some courses. I don't think this forum is meant for training you from scratch.

Regards,

Aditya

which type of problem show high vibration reading in vertical direction in bearing no.3 and no.4 of overhanging PA Fan .

I am beginning to agree with Aditya. You never answer any of our questions, designed to help us help you, you just come back with more questions.
You say you are a "trainee" at this plant, so WHO do you report to? Who is your "mentor"?
I cannot believe that you are just left to run around the plant looking for problems.

thank for suggestion.
sir,
presently i am handle cooling tower area of power plant.but one vertical cold water pump show high vibration readings in bearing no.2&3.
readings are
2 3
R1 10.7 6.5
R2 9.5 3.4
Rx 5.4 3.3

motor rpm -760
maintenance person's change empeller,coupling,
water seal etc.but no any improvment shows in pump condition.
please give me idea for indentfy the actual problem.

I would think he is part of the problem; not the solution. This would lend to the idea he will be finding new friends and travel opportunities in the near future.

Language seems a barrier here: he can't read what's being said but with the poor translator manage to be a ear-a-tator.

Hey; Tri-Path try 'babblefish'. Could the clue be in the name?

neeraj,
You start with how to static balance a fan, and NOW we learn you may be talking about cooling tower fans. Please calm yourself and study a good book on "vibration analysis and balancing".