Process for estimating the residual life of the electromagnet of a vibrating feeder of articles

A process for estimating the residual life of a vibrating feeder of articles, the vibrating feeder comprising:

• at least one electromagnet driven by a control circuit to make at least one element of the feeder vibrate in frequency, the electromagnet comprising a coil;
• the control circuit, with fixed or multiple channel and fixed or variable frequency, comprising, mutually operatively connected:
• a Hall effect sensor;
• a differential amplifier;
• a comparator;
• and
• an integration circuit for controlling the speed and displacement of a power supply element,
• the control circuit comprising a dedicated stage suitable for maintaining a galvanic separation between a high voltage part where measured electric current flows and a low voltage part of a signal processed to measure, moment by moment, the absorbed current and the operating voltage of the at least one electromagnet,
• the process comprising the following steps:
• constantly monitoring the waveform trend of the absorbed current I and the operating voltage V to calculate an ohmic resistance value of the at least one electromagnet, to be compared with a reference value;
• determining a residual margin before the magnetic saturation of the at least one electromagnet, a reading of an operating parameter obtained from a direct reading of the current allowing to know the working efficiency of the reel, then any residual margin before saturation to increase system performance;
• determining an air gap, through the operating parameter obtained from a direct reading of the current, namely a magnetic induction of the feeder, the parameter allowing to derive the appropriate air gap between the coil and the armature thus facilitating the calibration operations of the vibrating drive and at the same time providing feedback on the efficiency of the feeder;
• comparing the measurement of the density of a magnetic flux Bm with respect to a reference saturation limit value Bsat of the at least one electromagnet, through a value of the inductance L on the basis of the acquisition of the current value I absorbed;
• verifying an efficient operating situation of the vibrating feeder through the condition ε1=Bm−Bsat<0;
• wherein a correlation between the supply voltage and the supplied current provides the ohmic resistance value of the coil, the value, compared instant by instant with that declared by a manufacturer, providing an index of the coil consumption, and therefore of its remaining life cycle,
• the process including the following steps to derive an inductance value L based on the acquisition of the absorbed current value I:
• sampling an electric current signal I0 with a period Tk;
• calculating the inductance L given by the ratio between the integral of the supply voltage ViTk and the amplitude of a current sample ITk, the integral of the supply voltage ViTk calculated between the start of the measure, t=0, and the instant to which the sampling refers, t=t0, with t0∈Tk, the amplitude of the current sample ITk referred to the instant t=t0, with t0∈Tk, the inductance L and, starting from a constant value L0, corresponding to the manually set air gap, capable of varying between a minimum value Lmin, with maximum air gap, and a maximum value Lmax, with minimum air gap, during the normal harmonic oscillation of the armature in the vibrating feeder;
• the process further including the following step to derive an inductance value L based on the acquisition of the absorbed current value I:
• calculating the average inductance KLT in a period T given by the ratio between the integral of the supply voltage ViT and the intensity of the current IT, the constant supply voltage Vi, if applied at the input of a pulse width modulator AB of a circuit that has a PWM that uses IGBT, the variable supply voltage Vi, if applied at the input to a phase shifter CD that uses TRIAC, distinguishing between the intensity of current supplied by the electrical network to the coil of the electromagnet IA or IC and the intensity of current released by the coil in the electromagnet to the electrical network IB or ID, distinguishing between the amount of charge electricity supplied by the mains to the coil in the electromagnet QA or QC, integrating the current signal IA or IC in the half-period [0;
• T/2] and the quantity of electric charge released by the coil in the electromagnet to the mains QB or QD, integrating the current signal IB or ID in the half-period [T/2;
• T], the difference between the two quantities of electric charge thus calculated Q=QA−QB or Q=Qc−QD being responsible for the actual movement of the vibrating unit generating mechanical and magnetic losses, the intensity of current IT responsible for the effective movement of the vibrating unit generating mechanical and magnetic losses, obtained with a shunting operation in the period T of the actual electric charge quantity Q.