The motor power (7.5 kW) is lower than the shaft power of the pump (8.2 kW); will this have an impact on the motor?

Shaft power is merely the power required by the pump; in fact, the motor consumes power during operation； The current power of the pump is 8.2 KW, but in reality the motor’s output power should be around 12 KW; therefore a 7.5 KW motor was chosen. There is a significant difference, which leads to the motor being overloaded. The smaller motor may burn out, while an oversized motor could also cause accidents

Why is it 12Kw, not 1.1~1.2 times?

A small horse pulling a heavy cart leads to motor overload, which can easily cause the motor to burn out

Typically, motors have mechanical losses such as component gaps after assembly; after removing these mechanical losses, the actual effective power is around 70%.

When operating under the rated conditions of the water pump, the motor generates heat over time, which leads to reduced insulation and damaged bearings, eventually resulting in failure； If the water pump operates at a slightly higher flow rate, the motor will overheat severely and may burn out in a short period of time.

Bro, let’s make a deal – 12KW. Why be so picky? Low power is multiplied by 1.25··············

2# is right; the direct effect is an increase in current, which causes the motor to heat up. As for how hot it gets, based on the power levels you mentioned, there shouldn’t be any long-term effects; it will just get damaged in a short period of time. Mechanical equipment with such a configuration involves many components, leading to high levels of wear and loss; if any of these components fail to perform properly, efficiency will be significantly reduced. Therefore, in practice, a more conservative approach is taken when selecting such equipment, resulting in a higher power rating.:)

Just based on the numbers, the motor is definitely overloaded

This post was last edited by 3983596_FPPZ on 2018-10-24 at 12:49. The mechanism by which a motor burns out due to overload is as follows: when the load exceeds the motor’s rated capacity, the motor’s speed decreases, the slip rate increases, and the rotor’s rotation frequency becomes out of sync with the electrical frequency. This results in more severe interference between the magnetic fields generated by the rotor and those of the stator, leading to an increase in the induced current in the rotor. This in turn generates greater torque. The strong magnetic field produced by the rotor’s induced current exerts a force on the windings, causing large induced currents in those windings as well. As a result, the heat generated in the windings increases sharply; since heat dissipation remains unchanged, the insulating coating on the windings melts away, reducing their insulation properties and leading to short circuits in the windings, which ultimately causes them to burn out instantly. The advantage of motors is that they can automatically reduce their speed to increase torque when faced with high loads; however, a too large reduction in speed can lead to damage, which is a disadvantage. Short-term overload operation is generally acceptable (such as during startup), but if the overload persists for a long time, the heat generated cannot be dissipated, and this can result in damage to the motor. It is recommended to use an 11KW motor, or reduce the load