Efficiency
The General Directorate Energy of the Europeam Commissionand CEMEP as an association of the European motor and
drive manufacturers have, in a Voluntary Agreement, settled
to classify three-phase low voltage
induction motors ac-
cording to their efficiency. The Agreement includes all two-pole
and four-pole standard motors in the output range between1 and 100 kW, and the classification is done by labelling themotors with one of the three classes eff1, eff2, eff3, where eff3
is attached to motors with nowadays usual efficiencies, eff2
belongs to motors with significantly increased efficiencies, and
eff1 is a mark for high-efficiency motors. In the Agreement is
specified, to mark the motors on the nameplate with the res-
pective lass and to declare the respective classes for the
motors in technical catalogues, moreover, in the cataloguesmust be specified data about efficiencies at partial loads. Inthe Agreement the DIN EN 60034-2 is expressly specified as
the test procedure for determination of loss and efficiency. The
mark for the efficiency classes is a Registered Trademark. VEM
is among the subscribers of this Voluntary Agreement.
For the North American market, with respect to efficiency ofthree-phase low voltage motors the legal provisions of the so-
called EPAct (or EPCA = Energy Policy and Conservation Act)
are in force, by them, depending on the pole-number, are alsominimum efficiencies determined (Table 12.10 of NEMA MG1or Tables 2 and 3 of CSA C390). The output range of the
affected motors is between 1 and 500 hp in NEMA MG1, and
between 1 and 200 hp in CSA C 390. When classifying Euro-
pean motors according to the American rules, attention must
be paid to the fact that the test procedure for determination
of loss and efficiency is expressly specified with the Standard
IEEE 112, and that, when using this procedure for determina-tion of efficiencies, the results will have significant deviationsfrom those of DIN EN 60034-2, i.e. it results in considerably
lower efficiencies. Motors of the VEM series WE1R are certified
by CSA according to CSA C390.
VEM motors are equipped with bearings from excellent manu-
facturers. The bearings have a nominal service life of at least
20,000 hours for maximum permissible load conditions. With-
out additional axial loading for coupling service the nominal
bearing service life is 40,000 hours.The versions -fixed bearing N-end-without fixed bearing
-permanent lubrication
-relubrication device
-heavy bearing arrangement D-end (for increased lateral forces)-easy bearing arrangementand the-bearing schedules-disc spring and wave washer schedule
-V-rings
-figures of bearing arrangements
-flat grease nipplesare shown in the bearing arrangement tables. Fixed bearingD-end possible on request. Any grooved
ball bearings supplier have
disc springs and wave washers, respectively, thus they are preloaded. This is not true for ver-sions with cylindrical
manufacturers of roller bearings. Theversion "fixed bearing N-end" is possible for motors"without fixed bearing". Motors with permanent lubrication are also available with adegree of protection IP 56.Motor sizes 56 – 160 are fitted with life-lubricated bearings. Formotors from size 180, depending on the useful life of grease, bearings must be regreased in good time so that the scheduled bearing service life is reached. Under normal operating con di-tions, the grease packing will last for 10,000 hours of operation with 2pole version and for 20,000 hours of operation with ver- sions from 4poles upwards without being renewed. For mo torsfitted with relubrication device and working under normal oper- ating conditions, the grease will last for 2,000 hours of operation with2pole version and 4,000 hours of operation with 4- and
mor-pole versi ons. The standard grease is a KE2R-40 type acc.to DIN 51825. Important Note:Radial forces below the minimum value can lead to bearing
damage within a few hours. Test runs in no-load state are
only permissible for a short period.
Use of cylindrical roller bearings
If the special minimum radial force cannot be met, we recom-mend the use of grooved ball bearings (easy bearing arrange-ment). Bearing change on request. Using cylindrical roller bearings (heavy bearing arrangement),
relatively high radial forces or masses can be accepted at
the motor shaft end, e.g. belt drives, pinions or heavy-duty
couplings.
The minimum radial force at the shaft end must be at least a
quarter of the permissible one. Account must be taken ofpermissible shaft end loading. Both these values are found inthe diagrams.
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