Laboratory centrifuge troubleshooting and troubleshooting

The motor does not start

(1) The main power indicator light is on, at this time should check the degree of carbon brush wear, if the carbon brush wear more than one-third of the total amount, should be replaced with a new carbon brush in time.

(2) When the main power indicator is not on, check whether the indicator fuse and the indoor distribution board fuse are blown, and check whether the power cord is in good contact, if the fuse is broken, replace the fuse and keep the circuit unblocked.

(3) The vacuum pump meter and oil pressure indicator value should also be checked, if the oil pressure is too high and the main engine can not be started, it is necessary to check whether the oil circuit is blocked, especially whether the throttling hole is unblocked, if it is not smooth, it should be cleaned to make it unblocked.

(4) The bearing is damaged or the rotation is blocked, the bearing lacks oil or there is more dirt in the bearing and the friction resistance increases, the motor cannot reach the rated speed, and the bearing should be cleaned or replaced in time.

(5) There is a layer of oxide on the surface of the commutant, and even if it is uneven or the brush does not match the outer edge of the commutator, the speed can also be reduced, and the commutator and brush should be cleaned to make good contact.

(6) If there is a short circuit or open circuit in the rotor coil, you can check it with a multimeter and rewind the coil. When the rotor is in use, the centrifuge tube can be ruptured, the sample leaks, and the rotor is damaged due to metal fatigue, overspeed, overstress, chemical corrosion, improper selection, unbalanced rotor and temperature runaway.

For the above situation, the operator is mainly required to master the operation procedure, correctly select the appropriate centrifuge tube and centrifugal rotor, pay attention to strictly control each step of the operation sequence, minimize unnecessary damage to man, and use it within the safety factor and guarantee period of the rotor.

Power supply issues

(1) The power supply is one of the reasons for the poor starting and cooling effect of the freezer, which is the same as the failure of the motor not turning, and the power supply and fuse should be checked separately.

(2) The voltage is too low, the safety device failure can also make the freezer unable to start, the voltage is too low may be the grid voltage is low; excessive wiring of the distribution board; The power cord is too long (ideally 3 meters), etc. The power line capacity is not enough, which not only reduces the voltage, but also causes accidents. When the power supply voltage drops to 180~190VJ, the freezer cannot be started, which affects the refrigeration effect.

(3) Poor ventilation performance, such as the instrument installed in direct sunlight or poor ventilation, poor radiator effect, or radiator covered with dust, will also affect the cooling effect.

(4) The weight of the centrifuge tube is unbalanced and the placement is asymmetrical; There are foreign objects in the rotor hole, which makes the load unbalanced; The fixing nut at the upper end of the shaft is loose, and the shaft is rubbed or bent; The motor rotor does not produce noise when it is not in the center of the magnetic field; Damage to the rotor itself can lead to severe vibration and abnormal sound of the body.

Most of the above reasons are caused by incorrect operation, and after finding out the cause, the correct operation can eliminate the abnormal phenomenon. In the process of work, if any abnormal phenomenon occurs, it should be stopped immediately, and it should not be forced to operate, so as to avoid unnecessary losses.