Investigation of the Effect of the Voltage Drop and Cable Length on the Success of Starting the Line-Start Permanent Magnet Motor in the Drive of a Centrifugal Pump Unit

Abstract

The use of Line-Start Permanent Magnet Synchronous Motors (LSPMSM) improves the efficiency of conventional direct-on-line electric motor-driven fluid machinery such as pumps and fans. Such motors have increased efficiency compared to induction motors and do not have an excitation winding compared to classical synchronous motors with an excitation winding. However, LSPMSMs have difficulty in starting mechanisms with a high moment of inertia. This problem can be exacerbated by a reduced supply network voltage and a voltage drop on the cable. This article investigates the transients during the startup of an industrial centrifugal pump with a line-start permanent magnet synchronous motor. The simulation results showed that when the voltage on the motor terminals is reduced by 10%, the synchronization is delayed. The use of the cable also leads to a reduction in the voltage at the motor terminals in a steady state, but the time synchronization delay is more significant than that with a corresponding reduction in the supply voltage. The considered simulation example shows that the line-start permanent magnet synchronous motor has no problems with starting the pumping unit, even with a reduced supply voltage. The conclusions of this paper support a wider use of energy-efficient electric motors and can be used when selecting an electric motor to drive a centrifugal pump.

A New Method of Reducing the Inrush Current and Improving the Starting Performance of a Line-Start Permanent-Magnet Synchronous Motor

“…Summarising the above considerations, it can be said that when designing LSPMSMs, the steady-state performance (efficiency, power factor, and synchronous torque) must be met together with the requirements regarding the start-up process (starting torque, pull-in torque, and braking torque) [1][2][3]15,16,26] while ensuring that the magnets are resistant to partial demagnetisation. This is because, as mentioned in the introduction, the magnets' resistance to demagnetisation decreases with increasing starting current and magnet temperature.…”

“…The problem of the partial demagnetisation of magnets and the possibility of irreversible deterioration of the performance of LSPMSMs have been analysed in detail in [8,13,14], among others. Furthermore, large inrush currents and accompanying voltage drops in the power supply network can make it difficult to start a motor (and even to fail synchronization) and can cause interference with the operation of other electric consumers that are supplied by the same network [15].…”

Optimal Rotor Design and Analysis of Energy-Efficient Brushless DC Motor-Driven Centrifugal Monoset Pump for Agriculture Applications

“…A steady liquid flow is provided by the centrifugal pump, and the liquid is drained without harming the impellers. The centrifugal pump is highly effective and appropriate for agriculture applications [17,18]. The monoset pump is developed to avoid transmission losses.…”

Comparison of Differential Evolution and Nelder–Mead Algorithms for Identification of Line-Start Permanent Magnet Synchronous Motor Parameters

“…LSPMSMs face some difficulties in starting and synchronization processes, especially with loads with a high moment of inertia [22][23][24]. An LSPMSM lumped parameter model [25] was applied to estimate the successfulness of starting and further synchronization, which has been extremely beneficial for the experimental verification of LSPMSM characteristics.…”