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  • Writer's picturePM S.r.l.

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As stated during our newsletter of January, we begin today this itinerary that will bring us to examine the principal problems which can occur during the use of your electro pumps.

First of all it is necessary to fix an essential rule, which is that a correct motor/pump coupling is indispensable for the good operation of the machine.

In fact, if you want to couple a motor and a pump purchased individually, you have to respect the following procedures:

  • Initially you have to verify the integrity of the pump’s packaging, but above all of the motor. In case of damage, you have to verify that motor doesn’t have any damages on the shaft’s head, which could have compromised integrity of the thrust bearing system. In the meantime a deformation of the sleeve could have compromised a good alignment of it.

ATTENTION: During handling, avoid to lift the motor acting on the cable. Strong pulls could compromise the isolation or the connection!!

  • Check if motor’s nominal power is equal or greater than that of the pump; if it is lower some overload and overheating problems can occur, reducing the life of the motor.

  • Effect the coupling aligning the pump with the motor, in order that motor’s prisoners enter in the respective holes of the pump’s support and that motor’s shaft enters in the joint of pump’s shaft aligning the teeth. The insertion must result sliding, without forcings.

  • Go forward screwing nuts, having care to proceed crosswise and several times, and making sure that pump’s support matches perfectly with motor’s support without any jamming. Once operation is finished, visually check, from at least two different point of view at 90°, that there is a good motor/pump alignment and that the shaft freely turns .

  • Finally, take care to arrange the motor’s cable along the pump in the intended area, protecting it with the specific well fixed metallic duct.

ATTENTION: Before installation inside the well or tank, keep all the motor/pump system vertically or, if it is horizontal, this must be placed on the whole length in order to avoid hits during a possible transport which could modify the alignment. This is particularly important in case of coupling with really long pumps!!

Next time we will start to analyse from time to time some practical issues following four principal “step” which will take us to their resolution:

  1. Identification of the problem;

  2. Subdivision of the problem in a mechanic, electric and hydraulic problem ;

  3. Recognition of the possible causes;

  4. Resolution of the problem.

Following this process in the order mentioned here above, we will go to analyse different kind of problems.


The first problem that we are going to deal with will concern the case in which pump runs but will not deliver water.

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