Siemens Motor

You have a leak ?

Try contacting your local Siemens dealer (http://w1.siemens.com/entry/cc/en/)

well, there is a sign of leak but why it is leaking? this is what i want to know

There's a sign of a leak but you haven't investigated where that's coming from, you just top up the oil ? Well that's one form of "maintenance" I suppose.

If you want to know where it's coming from I suggest you and your maintenance team have a darn good look. None of us can solve it from here with a one sentence clue ! Geesh! Are you actually an engineer? Where are your problem solving skills ?

A child could tell you that things leak when they're broken - so either the seals are worn or perished or the casing is cracked. Hardly degree level thinking, in fact it's not even specifically engineering thinking.

Cool down dear! This a new Motor and I am not excepting any worn-out at oil seal laby, sorry if I did not include much details. Anyhow, when I have look between the shaft and oil seal I observed the leak source but if the seal is still new and before request to s/d the Motor to open the bearing for seal inspection, what things could I look to. I appreciate your understanding. In addition to that I noticed Plant air is connected to the Motor, but what is the purpose of it actually I don't know because I am Mechanical Inspector and I don't have much experience in Motor.

If plant air is connected to the motor then it is probably a purge to slightly pressurise the motor to avoid an explosive gas mixture accumulating. You can not switch it off, but check whether it is supplying too much air. This could be slightly pressurising your bearing housings and forcing oil past the labyrinth seals. This can be verified by checking if there is air coming out of the bearing breathers.

I have checked it and I can feel the amount of air coming from seal area not from the breather but I am not sure maybe this air caused by rotation of the shaft?, do you recommend to open the breather for more confirmation? And do you know how much required air pressure?

Thanks in advanced

This a new Motor and I am not excepting any worn-out at oil seal

So as I suggested in post #1 - get the supplier back in to sort it out under warranty. And RTFM. One more thought: are maintenance using the correct bearing oil?

And please, in future, if you're asking for our help - give as much detail as possible up front - there are too many numpty questions on here and we do all bite. A well phrased question, showing what you've looked at and what you think will get sensible answers and suggestions. If it's a basic question but out of your field, then say so and the reception will be warmer.

Good luck getting it sorted.

thanks a lot, I have contacted Siemens.

Are you an Engineer? If you are, you lack professionalism.....we should focus on helping this gentleman with the problem and keep negative criticism to ourselves.

there is a sign of leak .
You need to learn to read the signs...where is it?
Is it the sign of seepage, or dripping or a cracked gasket, or a loose bolt, or a worn seal, worn bearing....
Keep asking yourself why and look closely...play the detective.
Del

thanks, for your comments and advice

Hello,

Check whether seals are provided in the motors. If seals are there then there may be leakage because of wear out of seals. Ensure alignment of shaft before fitting seals.

Thanks dear, will consider your point

If you are topping up oil and not seeing signs of an oil leak, then it is possible that the oil is being sucked in across the inner labrynth seal into the stator cavity. The action of the rotor fan can cause a suction effect, where the presure in the bearing housing is greater than the pressure in the stator cavity. This will be assisted if you have a positive pressure applied to the bearing housing. It is possible that the applied Plant air supply is connected to the wrong side of the inner labrynth seal. The applied pressure should be on the inner side of the laby seal, that is, on the side adjoining the stator cavity.

Check also whether there is an air-flow channel connecting the inner side of the laby seal to the atmosphere, and whether this channel is plugged. Some motors are fitted with this feature to ensure that the inner side of the laby seal runs at a higher pressure than the bearing housing cavity, so this prevents migration of oil across the inner laby seal.

In case of oil sucked in, is it going to harm the Motor?And is there any way to check if there is oil goes inside the Motor or not?

This is very true .It happens on motors having bearing mounted on the end shields.The oil is sucked in and Insulation deteriotes.This is avoided in motors having independent pedestal mounted bearings

What kind of lubrication system does the motor have? Does it have glass canister oil resevoirs on each bearing housing?

Yes it does.

Three situations that I have encountered: (This applies to the sleeve bearing system were the top portion of a bronze ring rests on the turning shaft and the bottom portion of the rings dips into the oil resevoir.

1. Oil resevoir canister must be sealed air tight. Top center there is a screw where oil is replenished. This screw must be tight enough not to let air into canister.

2. Oil site glass half way mark is to high in comparison to the lower portion of the shaft (oil will be sucked into motor if level within bearing is too high). Level should be just high enough so that lubricating ring dips into oil.

3. If you stand in front of shaft end and motor rotation is clockwise, the oil resevoir canister should be on your left hand side of the motor. If the canister is on the right side the rotor will be subjected to more suction from the motor rotor.

4. If Labrynth seals have too much clearance, motor rotor suction will pull oil into motor.

u just check its oil seal size because after long time the groov developed on shaft & alos oil seal gets heat while in running condition & finally its start to deforming & resulted that sealing gone this is the reason .

onemore thing that if shaft groov is there then correct the groovs by nulling method of shaft & after just calibrate the shaft OD & fixed new oil seal as per shaft OD . Give clearance between shaft OD & poilsael ID is less tehn -0.4 mm.

bye