Tuesday, January 9, 2018

Insulated bearing has NOT stopping in 2018

Have you experienced bearing failure in electrical equipment? Do you know why insulation is needed in motor & generator?
OPEN IN WEB
Insulated bearing has NOT stopping in 2018
 

Electric motors, generators and associated equipment are at risk when an electric current passes through their bearings. This can damage the contact surfaces of rolling elements and raceways in the bearings (electrical erosion) and rapidly degrade the grease. An additional risk in electric motors and generators comes from high frequency currents caused by the inherent stray capacitance. The risk of damage increases where the application uses a frequency converter. Thus here come INSULATED bearings, which usually means coated bearings, ceramic hybrid bearings or full ceramic bearings.
Worldwide famous insulated bearing producers include SKF (INSOCOAT Bearing), NTN (MEGAOHM Bearing), FAG (J20A/B/C Bearing), NKE (SQ77/E Bearing) & etc.

Here we take item 6226M/C3VL0241 for example:

Basic technical data for reference:
Coating Layer Thickness: 0.2-0.4mm
Breakdown voltage: min 1000V
Electrical resistance: min 50MΩ
Insulated Material: Zirconia/ Alumina/ Titanium oxide
Typical applications: Traction motors of railway vehicles/ Electric motors (AC/DC)/ Generators

Different meanings of suffix in Worldwide brands:
SKF INSOCOAT Bearing
 
VL0241:  >1000V DC,  >50MΩ, outer ring insulated
VL2071:  >1000V DC,  >50MΩ, inner ring insulated
VL0244:  >2000V DC,  >150MΩ, outer ring insulated
VL2074:  >2000V DC,  >150MΩ, inner ring insulated
VL0246:  >3000V DC,  >50MΩ, outer ring insulated
VL2076:  >3000V DC,  >50MΩ, inner ring insulated
 
Know more
FAG Insulated Bearing
 
J20C: insulation on the inner ring  
6332-J20C-C3/ 6328-M-J20C-C3/ 6332M.C3.J20C

J20C/ J20A/ J20AA/ J20B: insulation on the outer ring
6220-2RSR-J20AA-C3/ NU214-E-M1-F1-J20B-C4  

Ceramic Hybrid Bearing: HC6214-M-P6-C3
 
Know more
NKE Insulated Bearing
 
​Insulation on the outer ring: SQ77
6330M/C3SQ77   6330-M-C3-SQ77

​Insulation on the inner ring: SQ77E
6330M/C3SQ77E   6330-M-C3-SQ77E

​Hybrid Bearing: 6302SQ77B
Know more

Typical items in different applications:
Wind turbine generators: 6326C3VL2071,6328C3VL2071,6330MC3VL2071,6332MC3VL2071
Electric motors: 6317MC3VL0241,6319MC3VL0241,6322MC3VL0241,NU330ECMC3VL0241
Traction motors of railway vehicles: 6016MC4VL0241,NU214MC4VL0241,6311MC4VL0241
 

Installation Notice:
1.     Installation: Insulated bearing is of high precision, wrong installation easily leads to bearing raceway damages. These bearings should be installed with help of special molds carefully.
2.     Prevention: Dynamic balance measurement for generators should be done before bearing installation in order to avoid iron fillings occurred during dynamic balance measurement running into the bearings.
 

If you have any needs of insulated bearings, just contact TBB

Advanced Holiday Notice
TBB office will be closed for annual Chinese New Year shutdown from Feb 14th to 25th 2018. 
Please make a note.  

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