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Advantages of using the high performance Grease Mobil Polyrex TM EM Electric motors grease lubrication MCM Verona 28 October 2015 Paolo Burchianti LFE Esso Italiana 2009 Exxon Mobil Corporation. All rights reserved
Agenda Electric motor grease trends Major OEMs and bearing suppliers Grease requirements for electric motors ExxonMobil s vision for Polyrex EM Critical performance characteristics Grease compatibility Performance summary 1
Electric Motor Lubricating Grease Trends Increasing power density Motors are becoming smaller for given power output Speeds and operating temperatures are increasing Greases required to last throughout motor s life : Fill for Life Requires balance of bleed characteristics, oxidation stability and structural stability Grease is considered a fundamental component of premium electric motors Grease requirements are specified by OEM as integral to new designs Increasing need for quieter greases for noisesensitive applications Automotive under-the-hood application Consumer goods 2
3 Electric Motors - Major OEMs
4 Electric Motors Major Bearing Suppliers
5 Electric Motor Design
Grease Requirements For Electric Motors Good channeling characteristics NLGI Grade 2 or 3 3 grades used where dn>250,000 (dn=bore(mm) x rpm) 500-650 SUS @100 F (c.ca 38 C) base-oil viscosity (~100cSt @ 40 C) High dropping point Measured by ASTM D2265 450 F (232 C) minimum Low oil bleed characteristics Measured by ASTM D1742, ASTM D6184 or IP121 6
...More Requirements For Electric Motor Greases Excellent resistance to high temperature oxidation Usually measured by ASTM D3336 spindle life 500 hour minimum at top operating temp (300-350 F) (149-177 C) Good low temperature torque characteristics Usually measured by ASTM D 1478 Typically 10,000 g-cm max starting torque at -20 F (-29 C) Good anti-wear characteristics but generally non-ep 7
ExxonMobil s Vision for Mobil Polyrex EM To offer a state-of-the-art lubricating grease for use in electric motor bearings that: Sets new standards for long-life grease performance Allows bearing manufacturers to supply grease-lubricated bearings capable of offering longer life, low-maintenance service, on an unprecedented scale in the marketplace Offers low-noise performance desired for noise-sensitive applications 8
Mobil Polyrex EM Delivers STEP-OUT Performance Excellent high-temperature long-life lubrication Outstanding shear stability (mechanical stability) Excellent corrosion resistance Excellent oil bleed characteristics Good low temperature capabilities Good pumpability Increased compatibility with most conventional lithium greases 9
The Performance Breakthrough of Mobil Polyrex EM Extended life without compromise in other grease properties 10
ASTM D3336 Grease Life Test Test conditions 6204 bearing runs @ 10,000 rpm Light loading: 5 lb axial, 15 lb radial 350 F (177 C) bearing temperature Failure detected by an increase in bearing starting torque or a 27+ F temperature spike Duty cycle: 20 hours on, 4 hours off Mobil Polyrex EM achieves : >750 hrs. @ 350 F (177 C) 11
FAG FE9 Grease Life (Variation A) 165 Temperature ( C) to obtain 100 hr minimum life (L50) 160 155 150 145 140 135 130 Mobil Polyrex EM Competitor C Conventional Polyurea Conventional Li-Complex 12
Shear Stability Based on 100,000 Penetration 120 100KX 60X Penetration, Mm/10 100 80 60 40 20 0 Mobil Polyrex EM Competitor C Conventional Polyurea Conventional Li-Complex 13
Anti-Wear Protection Wear protection is measured in the 4-ball wear test (ASTM D 2266) Test conditions Spinning ball rotates against 3 stationary balls Load on spinning ball = 40 kg Test temperature = 167 F Speed of rotating ball = 1200 rpm Test duration = 1 hour Diameter of circular wear scar on stationary balls is measured in mm Industry standard = <0.5-0.6 mm scar Mobil Polyrex EM achieves : 0.4 mm scar 14
Mobil Polyrex EM Exhibits Excellent Water Resistance Water washout test (ASTM D1264) Bearing tested in a shielded, but unsealed housing Test temperature = 79 C Typical lithium complex grease achieves 3-5% washout Mobil Polyrex EM achieves 1.9% 15
EMCOR Rust Test Bearings run in duplicates Rating scale is from 0 to 5 0 = no corrosion 5 = severe corrosion Mobil Polyrex EM achieves 1, 0 rating Rating 0 Rating 5 16
Mobil Polyrex EM Controls Oil Bleed Controlled oil bleed is key to achieving long lubrication life ASTM D1742 oil separation test Predicts the amount of static oil separation at 25 C Measures the amount of oil bleed through a wire mesh with 0.25 psi pressure on the grease Typical Lithium Complex greases achieve <3% oil bleed Mobil Polyrex EM achieves 0.5% 17
Mobil Polyrex EM Controls Oil Bleed Controlled oil bleed is key to achieving long lubrication life ASTM D6184 high temperature oil bleed test Measures oil bleed through a wire mesh at 100 C (30 hours) Low bleed is critical for long-life performance at high temps Mobil Polyrex EM achieves <0.1% bleed 18
Mobil Polyrex EM Controls Oil Bleed IP 121 oil bleed test Similar equipment set-up as ASTM D1742 IP 121 tests run on Mobil Polyrex EM and Competitor C at 40, 70, 120, and 150 C Oil bleed measured at times ranging from 42 hours to 1 week. See graph for details 19
IP 121 Oil Bleed Results 35 30 IP 121 oil separation @ 70 C, 120 C and 150 C 150 C Oil Separation (%) 25 20 15 10 5 0 0 20 40 60 80 100 120 140 160 180 Time (hours) 120 C 150 C 120 C 70 C 70 C Polyrex EM @ 120 C Competitor C @ 120 C Polyrex EM @ 150 C Competitor C @ 150 C Polyrex EM @ 70 C Competitor C @ 70 C 20
Mobil Polyrex EM = Excellent Overall Performance Oil Bleed Mobil Polyrex EM exhibits controlled oil separation even at high temperatures Shear Stability Mobil Polyrex EM exhibits significantly improved shear stability over conventional polyurea greases Compatibility Mobil Polyrex EM exhibits enhanced compatibility with Licomplex and other Polyurea greases Mobil Polyrex EM Bearing Life Mobil Polyrex EM exhibits 3 to 7 times longer bearing life than conventional electric motor greases Noise Performance Mobil Polyrex EM uses a controlled proprietary manufacturing technique to deliver consistent low-noise performance 21
Grease Compatibility Guide Grease Compatibility All Mobil electric motor greases are compatible or moderately compatible with each other Mobil Polyrex EM Mobil Polyrex EM 103 Unirex N2 Unirex N3 Mobilith SHC 100 Mobiltemp SHC 100 Mobil Polyrex EM Mobil Polyrex EM 103 Comp Unirex N2 Comp (FE9) Unirex N3 Comp (FE9) Mobilith SHC 100 Comp Mobil temp SHC 100 M-Comp Comp r/a r/a r/a M-Comp Comp (FE9) Comp (FE9) r/a Comp M-Comp r/a r/a Comp M-Comp Comp Comp r/a M-Comp M-Comp Comp M_Comp M-Comp r/a Comp Comp Compatible Moderately Compatible Incompatible 22
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