Message Board Thread - "Severity criteria for (Mechanical Equipments)"

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Severity criteria for (Mechanical Equipments) Hamlet 10/25/2006
Could you provide me a severity criteria for motors, in general for mechanical equipments?

Thanks in advance
 
Re:Severity criteria for (Mechanical Equipments) Raphael Danjoux 10/26/2006
A) For components that are lubricated, the maximum allowable temperature is that of the oil.
B) Delta T criteria : hard to say because it is case by case. Criteria such as the one used for electrical inspection can be a first basis, but you'll have to determine your own set of thresholds.
C) Maximum temperature criteria. Below are some examples in degrees Celsius.
Bearings, Rolling Element Types
Races (for metallurgical stability)……………………………………………………… 125
Rolling elements………………………………………………………………………… 125
Plastic retainer (cage)………………………………………………………………….. 120
Steel retainer (cage)…………………………………………………………………… 300
Brass retainer (cage)………………………………………………………………….. 300
Steel shield (closure)………………………………………………………………….. 300
Nitrile rubber lip seal…………………………………………………………………… 100
Acrylic lip seal………………………………………………………………………….. 130
Silicone lip seal………………………………………………………………………… 180
Fluoric lip seal………………………………………………………………………….. 180
PTFE lip seal…………………………………………………………………………… 220
Felt seal………………………………………………………………………………… 100
Aluminum labyrinth seal………………………………………………………………. 300
Bearings, Plain Types Material
Tin base babbitt...……………………………………………………………………… 149
Lead base babbitt……………………………………………………………………… 149
Cadmium base…………………………………………………………………………. 260
Copper lead…………………………………………………………………………….. 177
Tin bronze………………………………………………………………………………. 260
Lead bronze……………………………………………………………………………. 232
Aluminum……………………………………………………………………………….. 121
AC Motors, Field Windings :
1.00 SF, class A……………………………………………………………………….. 100
1.00 SF, class B……………………………………………………………………….. 120
1.00 SF, class F……………………………………………………………………….. 145
1.00 SF, class H……………………………………………………………………….. 165
1.15 SF, class B……………………………………………………………………….. 130
1.15 SF, class F……………………………………………………………………….. 155
DC Motors and Generators, Windings :
1.00 SF, class A……………………………………………………………………….. 110
1.00 SF, class B………………………………………………………………………. 140
1.00 SF, class F……………………………………………………………………….. 170
1.00 SF, class H……………………………………………………………………….. 195
1.25 SF, (2hr), class B………………………………………………………………… 120
1.25 SF, (2hr), class F………………………………………………………………… 150
Note : Casing temperatures may be lower than these specified windings temperatures.
Cylindrical Rotor Synchronous Generators, Air Cooled, Casing :
Class B…………………………………………………………………………………. 110
Class F…………………………………………………………………………………. 130
Class H…………………………………………………………………………………. 150
Bearings, Plain Types, Factory Produced
Rulon, filled PTFE……………………………………………………………………… 204
Graphite bronze………………………………………………………………………… 204
DU……………………………………………………………………………………….. 288
PTFE lined fibreglass…………………………………………………………………. 177
Nylon……………………………………………………………………………………. 149
Polyurethane…………………………………………………………………………… 082
Polyacetal………………………………………………………………………………. 104
Wood……………………………………………………………………………………. 071
Metalized graphite…………………………………………………………………….. 593
Pure carbon……………………………………………………………………………. 399
Polyolefin, UHMPW…………………………………………………………………… 082
Delrin…………………………………………………………………………………… 149
Zytel…………………………………………………………………………………….. 107
Teflon…………………………………………………………………………………… 288
Rubber…………………………………………………………………………………. 049
Lubricants (when used with polyamide plastic bearing retainer) :
Mineral oils without EP additives, ie., machine oils, hydraulic fluid……………… 120
EP oils, ie., industrial, automotive, gearbox oils…………………………………… 110
EP oils, ie., rear axle, differential, hypoid gear oils………………………………… 100
Synthetic oils :
Polyglycols, poly-olefins……………………………………………………………… 120
Diesters, silicones…………………………………………………………………….. 110
Phosphate diesters…………………………………………………………………… 120
Greases (mineral oil lubricant), lithium, polyurea, bentonite,
calcium complex……………………………………………………………. 120
Lubricants, Greases (mineral oil), when used with steel or brass retainer)
Lithium base…………………………………………………………………………… 110
Lithium complex………………………………………………………………………. 140
Sodium base…………………………………………………………………………... 080
Sodium complex………………………………………………………………………. 140
Calcium (lime) base…………………………………………………………………… 060
Calcium complex………………………………………………………………………. 130
Barium complex……………………………………………………………………….. 130
Aluminum complex……………………………………………………………………. 110
Inorganic thickeners…………………………………………………………………… 130
Polyurea………………………………………………………………………………… 140
Lubricants, Solid lubricant materials :
Graphite………………………………………………………………………………… 427
Molybdenum disulphide………………………………………………………………. 450
Tungsten disulphide………………………………………………………………….. 510
Polytetraflurethylene………………………………………………………………….. 300
Seals and Gaskets, elastomers :
O-rings and gaskets :
Butyl rubber……………………………………………………………………………. 107
Hypalon………………………………………………………………………………… 121
Epichlorohydrin rubber……………………………………………………………….. 135
Ethylene acrylic……………………………………………………………………….. 177
EPDM…………………………………………………………………………………… 149
Flourocarbon (viton, kalrez)…………………………………………………………. 204
Flourosilicone…………………………………………………………………………. 177
Neoprene……………………………………………………………………………… 149
Nitrile…………………………………………………………………………………… 135
Polyacrylate rubber…………………………………………………………………… 177
Polysulfide rubber…………………………………………………………………….. 107
Polyurethane………………………………………………………………………….. 093
Silicone rubber………………………………………………………………………… 232
Lip Seals :
Nitrile……………………………………………………………………………………. 121
Polyacrylate rubber……………………………………………………………………. 149
Silicone rubber…………………………………………………………………………. 163
Flourocarbon (viton, kalrez)………………………………………………………….. 204
Leather…………………………………………………………………………………. 093
Mechanical Seal Material (see above for elastomers) :
Stellite………………………………………………………………………………….. 177
Tungsten carbide……………………………………………………………………… 232
Stainless Steel………………………………………………………………………… 316
Ni-resist………………………………………………………………………………… 177
Bronze, leaded………………………………………………………………………… 177
Ceramic………………………………………………………………………………… 177
Carbon…………………………………………………………………………………. 275
Silicon carbide………………………………………………………………………… 1650
Glass-filled teflon……………………………………………………………………… 177
Power Transmission Components
V-belts………………………………………………………………………………….. 060
Chain drives : limited by maximum lube temperature.
Gear drives : limited by maximum lube temperature
 


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