High Bearing Temperatures in Motors

Was the unit running normally (for how long ?) and this just happened ?

Is this a new start-up ?

New Install, first time run ?

Was there a speed pick-up or other device bolted to an insulated bearing housing ? causing a ground loop ?

What type of temperature sensor ? Is the sensor correct for the readout module ? Is the module calibrated correctly ?

In addition to my last mail,

I request you to check the following :-

1. During Alignment activities, Also, Check the soft foot.

2. Avoid nos. of Thin shims. Nos. of shims must be limited to 3-5 Max. As, More nos. of thins shims cause soft foot.

Due to soft foot, Rotor magnetic center will change and will creates Vibration/Higher bearing temp.

With regards,

Nilesh.

Hi Jagdeesha,

Which make is the motor?. Is it reputed BBL,Crompton, Kirloskar make?. What is rated current at full load?. What is ambient temp.?. Is it properly aligned with compressor?.

Suresh Sharma.

ABB Make motor.. full load current 550, ambient 50deg. It is properly aligned with compressor

Hi Jagdeesha,

Normally these motors are designed for 40 deg C ambient any how that can not be the reason for it getting it hot. ABB is reputed make. There seems no apprent reason for it to get very hot. May be bearings are giving problem. I suggest please call their Service Engineer to check up the motor as it is still under guarantee period.

Suresh Sharma.

If these bearings are found in such place that penetrate through it the tench of field strengths of electromagnetic, then in these bearings are induced eddy currents and always they will warm these bearings.

Only reasonable solution it was that putting before the bearing of the screen, made from soft magnetically sheet metals.

have your vibration tech check it out, also have a electrician check to see if there is voltage on the armature, the vibration tech could check this if he is set up for a flux reading, you could try grounding the armature, check with the manufacturer. also are you lubricating with a compatable grease? polyurea in some motors not compatable with lithium type? LOL :)

Hi Jagadeesha; I browsed this tech. catalog from ABB motors and I saw a whole lot of information regarding your question, give it a read.

http://www.clrwtr.com/PDF/ABB-Motors/ABB-NEMA-Motors.pdf

Yahlasit

Have you checked belt tension?

If the tension is too high the bearings can be overloaded.

At 95 Deg C the bearing will not last much longer, typically once you get to 120 C, the bearing will self destruct. Depending on your operating duty cycle if operated 24 x 7, you may only see another7 to 10 days of bearing life.