It is caused by the adjustment of the balance disc and the process error during the overhaul of the segmented multistage pump. At this time, friction between the rotating part and the stationary part occurred, which overloaded the motor and the fuse was blown.
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For example, when the adjustment is wrong, the position of the entire rotor is incorrect, that is, the impeller is already in contact with the pump casing before the balance plate is placed on the balance ring. Rotation at this time is bound to cause friction between the impeller and the pump casing. And because the balance plate does not work at this time, the balance force cannot be generated, and the entire axial thrust is acting on the impeller, causing serious wear with the pump casing, causing the motor to overload and blow the fuse.
When the repair process is wrong, although the position of the rotor is also correct, the balance plate has too large deviation (or balance ring deviation), which makes it lose its balance function. Because when the scoop is too large, the pressure cannot be built up in front of the balance plate, and the backward balance force cannot be generated; in this way, the large axial thrust (several tons to tens of tons) generated by the impeller will pull the entire rotor into the water. Side movement causes friction between the balance plate and the balance ring at the maximum point, causing the motor overload fuse to blow.
The first phenomenon is less common, and the second phenomenon is more common. For example, in the past, there was a water pump that was overloaded after overhaul and the fuse was blown. After disassembling the inspection, it was found that the balance pan was too large, with an opening of 0.60 mm, and the contact area turned blue from friction. Later, the opening was eliminated to 0.15 mm, and the current was normal after starting.
Of course there are other reasons. For example, for a segmented multi-stage pump, there is a ø3/4 inch valve on the balance pipe from the balance plate to the pump inlet pipe area. Although the door was in the open position at the time, the valve flap actually blocked the passage of the balance pipe. , Causing the pressure to increase after the balance tube, the balance plate wears out, and the motor overload fuse blows.
Actually, there are many reasons for overload, but the overload caused by the malfunction of the balance mechanism is the most serious. In the case of a blown fuse, it is almost always caused by a malfunction of the balance mechanism.
