Nidec Leroy-Somer PLSES Series Installation & Maintenance

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6Installation and maintenance - Three-phase induction motors4850 en - 2018.11 / fASSEMBLY1.2 - StoragePrior to commissioning, machines should be stored in ahorizontal position:- Away from humidity: at relative humidity levels greater than90% the machine insulation can drop very rapidly, to just abovezero at around 100%. The state of the anti-rust protection onunpainted parts should be monitored.For very long storage periods the motor can be placed in asealed package (for example heat-shrunk plastic) containingsachets of desiccant.- Away from frequent significant variations in temperature, toavoid the risk of condensation. During storage the drain plugsmust be removed to allow condensation water to escape.- If the area is subject to vibration, try to reduce the effect of thisvibration by placing the motor on a damping support (rubberplate or similar) and turn the rotor a fraction of a turn once afortnight to prevent the bearing rings from becoming marked.- Do not discard the rotor locking device (where there are rollerbearings).Even if the motor has been stored in the correct conditions,certain checks must be carried out before it is started up:GreasingBearings which cannot be regreasedMaximum storage: 3 years. After this time, replace the bearings(see section 6.3).Bearings which can be regreasedGreasegrade 2Greasegrade 3Storage periodless than6 monthsless than1 yearThe motor can be commissionedwithout regreasing.more than6 monthsless than1 yearmore than1 yearless than2 yearsRegrease before commissioning,as described in section 3.1more than1 yearless than5 yearsmore than2 years andless than5 yearsDismantle the bearing- Clean it- Replace the grease completelymore than5 yearsmore than5 yearsChange the bearing- Regrease it completelyGreases used by LEROY-SOMER(see nameplate): - grade 3: ESSO UNIREX N 3- POLYREX EM1032 - ASSEMBLYElectric motors are industrial products.They must therefore be installed byqualified, experienced and authorized personnel. Thesafety of people, animals and property must be ensuredwhen fitting the motors into machines (please refer tocurrent standards).2.1 - Checking the insulationBefore starting the motor, it is advisable to checkthe insulation between the phases and earth,and between phases.This check is essential if the motor has been stored for longerthan 6 months or if it has been kept in a damp atmosphere.This measurement must be carried out using a megohmmeterat 500V D.C. (do not use a magnetoelectric system).It is better to carry out an initial test at 30 or 50 volts and if theinsulation is greater than 1 megohm, carry out a second test at500 volts for 60 seconds. The insulation value must be at least10 megohms in cold state.If this value cannot be achieved, or if the motor may have beensplashed with water or salt spray, or kept for a long period in avery humid place or if it is covered with condensation, it isadvisable to dry the stator for 24 hours in a drying oven at atemperature of between 110°C and 120°C.If it is not possible to place the motor in a drying oven:- Switch on the motor, with the rotor locked, at 3-phase A.C.voltage reduced to approximately 10% of the rated voltage, for12 hours (use an induction regulator or a reduction transformerwith adjustable outlets). For slip-ring motors, this test shouldbe performed with the rotor short-circuited.- Or supply the 3 phases in series with a D.C. current, with thevoltage at 1 to 2% of the rated voltage (use a D.C. generatorwith independent excitation or batteries for motors of less than22 kW).- NB: The A.C. current must be monitored using a clampammeter, and the D.C. current using a shunt ammeter. Thiscurrent must not exceed 60% of the rated current.It is advisable to place a thermometer on the motor housing: ifthe temperature exceeds 70 °C, reduce the indicated voltageor current by 5% of the original value for every 10° difference.While it is drying, all the motor orifices must be open (terminalbox, drain holes).MWarning: If the high voltage test, carried out atthe factory before dispatch, needs to be repeated,it should be performed at half the standard voltage, ie.:1/2 (2U+1000V). Check that the capacitive effectresulting from the high voltage test is eliminated beforeconnecting the terminals to earth.In all cases, compatibility of the motor and itsenvironment must be guaranteed before its installationand also throughout its life.For all insulation or dielectric tests, it is advisable toearth the thermal probes and/or accessories.