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absorbed by the EDM, but for MS driven with alternating voltage EDM, the
best characterization of loading is done using AEP evolution. In some papers
[4], [5] the AEP it is taken into account, but the research resources are not
completely exploited. This paper presents some experimental research results
based on a new approach on computer aided AEP monitoring for MS powered
by EDM.
2. EP Monitoring Principle on EDM and Experimental Conditions
Fig. 1 describes a computer assisted monitoring bench test developed for an
asynchronous EDM supplied on a three phase 50 Hz frequency sinusoidal
voltage, symmetrical network (3×380V). A single phase is used for computer
data acquisition (instantaneous current i(t) IC and voltage u(t) IV in time
Fig. 1 – Experimental features of the EP bench test.
evolutions [6] provided by two transformers CT and VT) via a numerical
oscilloscope (ADC 212/50, Pico Technology Limited, UK). The acquired data
are processed in a personal computer. The instantaneous electric power p(t)
evolution (IEP) is given by: p(t)=3·u(t)·i(t). The AEP (one value on each period
T) is given by:
(1)
T
1
3
P = ∫ p(
t)
⋅ dt = ⋅ ∫u(
t)
⋅i(
t)
⋅ dt = 3⋅U
⋅ I ⋅cosϕ
,
T T
0
T
0
where: T=20 ms is the period (reciprocal of the frequency f), U - the effective
(root mean square, RMS value) voltage, I - the effective current, φ - the angle of