An Approach on a Transient Regime of a CNC Machining Center Spindle Drive System Using the Active Electrical Power Evolution

Abstract

This paper proves in theoretical and experimental terms the availability for scientific research of the active electrical power absorbed by a CNC machining centers during a transient regime of the spindle motor (start/stop on 10,000 rpm) electrically supplied by an AC/AC converter. A simple computer assisted experimental setup (with transformers placed on the electrical supply system of the converter, signals acquire system) and processing procedures are used in order to produce a correct approach of spindle motor and converter behaviour concluded in condition monitoring and diagnosis. Some relevant results were obtained in description of active electrical power (energy) absorption during acceleration and negative power absorbed during deceleration by electrical braking, in the description of instantaneous power constituents (voltage and current) and evolution in frequency domain by fast Fourier transform. An experimental approach on energy conversion efficiency (converter input electrical energy into output mechanical energy of spindle motor) was done. As an interesting topic for future, these research achievements are available in the research of mechanical loading (torque) during cutting processes (cutting tool and process condition monitoring).

A Study on the Dynamics of an AC Induction Motor Rotor Based on the Analysis of Free Response at Impulse Excitation

“…When an electric motor (particularly an AC induction motor, ACIM) is used to drive a rotary machine, the evolution of the electrical absorbed power flow (an equivalent of the mechanical power flow delivered to machine) is useful for condition monitoring and diagnosis (if the active electrical power -AEP-is properly measured and processed). Some achievements on this topic (mainly in transient regimes) were previously discussed in several earlier published papers (Bumbu and Horodinca, 2022a, b;Horodinca, 2016a, b;Chifan et al, 2019). A particular topic is addressed in this work: on the behaviour of the ACIM rotor system as a single degree of freedom torsional vibratory system.…”

“…The motorized spindle used in CNC machine-tools (the ACIM rotor is also the spindle) can be fully considered as such a system. This topic was briefly addressed in a previous work (Chifan et al, 2019).…”

On the Behaviour of an AC Induction Motor as Sensor for Condition Monitoring of Driven Rotary Machines

“…First, it is based on a simple computer-assisted experimental setup with measurement devices placed on the electrical supply system of the AC induction motor. The measurement of instantaneous current and voltage acquisition is performed utilizing this setup [ 1 , 2 , 3 , 4 ], which can be easily used for any other AC induction motor. This indirect measurement has a second important advantage: it makes it possible to avoid a much more complicated setup for mechanical power measurement that requires a torque sensor and an instantaneous angular speed sensor to be placed on the AC induction motor rotor.…”

A Study on the Evolution of the Supplying Current Absorbed By an AC Driving Motor During a Transient Regime on a Lathe Headstock Gearbox

“…a machine-tool) and the evolution of AEP constituents: voltage, current and power factor (Bumbu and Horodincă, 2022;Horodincă, 2016) are useful indicators in rotary machine condition monitoring and diagnosis. Many papers in the literature focus on AEP evolution (measurement and processing, (Huzlík et al, 2013;Horodincă, 2016;Chifan et al, 2019)), generally based on the evolution of instantaneous voltage (IV) and current (IC) absorbed by the AC motor from the electrical supplying system (ESS). If a three phase ESS is used, generally the AEP delivered by each phase should be measured.…”

“…Here U and I are the IV and IC root mean square values, cos(φ) is called power factor (φ being the phase shift between IC and IV). The AEP evolution on machine-tools during stationary processes is a specific topic in (Liu et al, 2017;Miuraa et al, 2018), some of our previous researches were already involved in transient regimes description (Horodincă, 2016;Chifan et al, 2019). When we talk about transient regimes some supplementary resources are available related by the evolution of AEP constituents (U, I and cos(φ)).…”