Problems with shielded pumps
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:) For the shielding circulation pump of a household boiler, the shielding cover was damaged, which allowed water to enter the motor. After installing a new shielding cover, the motor started making a humming noise and would not rotate; it would spin when turned by hand. I thought the capacitor was faulty, so I replaced it, but that didn’t work either. Later I tried using a larger capacitor, one for a 750-watt motor – originally a 15 uf capacitor was used, but a 25 uf one also didn’t work. I’d like to ask experts what’s going on here
I feel like it’s because the motor stopped right at the gap in that magnetic field
This post was last edited by qwl on 2018-1-23 at 11:48. What is the gap between the rotor and the shield sleeve? Is the gap uniform? The imbalance of three-phase resistance.
For home use, single-phase power, capacitor-start type
For home use, two-phase power; the gap is fine, and there’s no lag at all
Household use involves single-phase electricity, with one live wire and one neutral wire
As I understand it, the motor of this canned pump uses capacitive phase shifting to enable the use of three-phase power as if it were single-phase power~~~~ This makes the problem easy to explain~~~~ The capacitors replaced later by the original poster were not compatible, resulting in an actual imbalance in the three phases~~~~ The symptoms are similar to those of a motor connected to three-phase power where one phase is missing: it makes a humming sound but doesn’t rotate~~~~ But it’s not actually a missing phase, so once enough starting torque is applied, it can still start rotating, though it will generate a lot of heat~~~~ Right, original poster?
I’m not sure about the issue with overheating, because this canned motor cannot run idle – its rotor needs water to flow through it. It seems to lack starting torque; it makes no difference whether a capacitor is installed or not. Is there a starting coil? This coil is broken