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The common breakdowns and obviate methods of centrifuges

1.  Motor often can not start in the using process.
(1)    When the indicator light of the main power supply is bright, you should test the wear level of the carbon brush. If the carbon brush is worn more than one-third of the total, you should change a new carbon brush promptly.
(2)    When the indicator light of the main power supply isn’t bright, you should test the fuse wires of the indicator light and the indoor switch panel, watch whether they are fusing or not. At the same time, you should test whether the power cord could contact well or not. If the fuse wire is fusing, you should change a new fuse wire and keep the circuit unimpeded.
(3)    In addition, you also should test the vacuum pump table and the oil pressure indicated value. If the oil pressure is too high, the main engine also can not start, you must test whether the oil line is blocked or not and whether the throttle ostiole is expedite or not. If they are blocked, you should clean to make them clear.
(4)    The bearing is damaged or its rotation is hindered. The shortage of oil or the existence of too much dirt in the bearing will cause the increase of frictional drag, and the motor can not reach extra rotate speed. At this moment, you should clean or change a new bearing in time.
(5)    A layer of oxide on the surface of the commutator, even the misfit of brush and commutator’s outer edge will make the rotate speed decrease. You should liquidate the brush and the commutator to make them contact well.
(6)    If the rotor coil is short circuit or open circuit, you can use multimeter to test and re-wind the coil. The centrifuge tube will rupture, the sample will leak and the rotor will be damaged in the use of rotor. These phenomena are often caused by metal fatigue, over-speed, overstress, chemical corrosion, inappropriate selection and incontrollable temperature.
2.  Some problems about issue
(1)    The strike and the poor cooling effect of the refrigerating machine maybe result from the disconnected power. You should test the issue and the fuse wire.
(2)    The strike of the refrigerating machine can also result from low voltage and incorrect installation. There are many reasons leading to low voltage, such as low voltage of power grid, excessive wiring on the switch panel and the over-length power line etc.(The ideal length of power line is 3M ) Insufficient capacity of power line not only will make voltage decrease, but at the same time, it also can lead to unexpected accidents. When the supply voltage reduces to 180-190VJ, the refrigerating machine can’t start and will affect the cooling effect.
(3)    The bad ventilated function, such as device is installed in the conditions with direct sunlight or bad ventilation, the effect of radiator is poor or radiator is fully covered with dust, also can affect the cooling effect.
(4)    Component of centrifuge tube is not balanced, and its asymmetric place; there are foreign bodies in the hole of rotor, so the load is unbalanced; the fixed nut in the upper end of the spindle becomes loose, the spindle is grinding or becomes curve; the rotor is not in the magnetic center of gravity; all these above reasons can lead to violent vibrations and unusual sounds of the machine.
Most of the above reasons are caused by incorrect operations. After finding the reasons, the correct operation can eliminate the abnormal scene. In the task process, when the unusual scenes display, the machine should be shut down immediately to prevent unnecessary losses.
3The maintenances and precautions of centrifuge
(1) The device of centrifuge should be placed in a suitable locale according to the function of centrifuge. Ordinary low-speed centrifuge (desktop) can be placed on rough, consolidated table-board. (Its base is equipped with a rubber suction feed, and it closes to the table-board by means of atmospheric pressure and its own weight.)
(2) High-capacity low-speed centrifuge, high-speed centrifuge and high-speed refrigerated centrifuge should be placed on the massy earth’s surface. The load should be balanced before selecting the appropriate task for the centrifuge; otherwise it will lead to severe vibration and damage the centrifugal rotor and spindle.
(3) The holder of centrifuge can start to work after installing a centrifuge tube. Empty holder operation is forbidden.