Boots – shoes – and leggings
Patent
1980-06-25
1982-10-26
Wise, Edward J.
Boots, shoes, and leggings
324 76R, G01R 2106
Patent
active
043565530
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
In an earlier proposal (U.S. application Gernot Schneider et al, Ser. No. 90,734, filed on Nov. 2, 1979), a measuring device was described in which in each period of a reference signal, a digital measuring value is determined in each case for the voltage and a separate digital measuring value is determined in each case for the current. In another proposal, disclosed in German laid-open specification DE-OS 27 107 12, a method is described for obtaining the power output developed in a network by transforming scanned values of voltages and currents into pulses, which have respective average time occurrences proportional to the voltages and currents respectively, temporarily storing the so-obtained pulses in digital memories, generating interpolated pulses with the aid of synchronous switches and a logical connecting network at a predetermined probability, and obtaining a resulting pulse sequence at a probability of pulse occurrence proportional to the product of interpolated and non-interpolated pulses.
SUMMARY OF THE INVENTION
In accordance with FIG. 2a, a measuring signal u(t), which is proportional to the voltage, is compared with a periodically varying, preferably a delta shaped reference signal U.sub.r (t) and a pulse sequence U.sub.b (FIG. 2c) is formed, which at a point of time t.sub.1, and at a point of time t.sub.2 of an intersection point P.sub.1 or P.sub.2 of the two signals u(t) and U.sub.r (t) changes its logical state. The pulse duration T.sub.1, that is to say the time difference (t.sub.2 -t.sub.1), is a measure for the average value U.sub.1 =(u.sub.1 +u.sub.2)/2 of the measuring signal u(t) in the period T.sub.r of the reference signal U.sub.r (t), wherein u.sub.1 and u.sub.2 indicate the instantaneous value of the measuring signal u(t) at the point in time t.sub.1 or t.sub.2. By means of scanning pulses of high frequency, the pulse sequence U.sub.b is scanned and a number of pulses corresponding to the pulse duration T.sub.1 are fed into a pulse counter. This number of pulses represent a digital measuring value for the average value of the voltage, which value is multiplied in an arithmatic unit with the digital average value of the current which has been ascertained in similar manner. One Thus one obtains a measure for the electrical power and through integration a measure for the electrical energy in the appropriate circuit.
Due to the finite frequency of the reference signal U.sub.r (t), a measuring error due to the set-up of the system itself results, when the measuring signal u(t) is not a constant, or is not a sinusoidally varying parameter quantity of low frequency. Thus, to give an example, when measuring the electrical power in an alternating-current power-supply, harmonics of the fundamental frequency which might be present, can not be detected in a correct manner. It should be pointed out, that the measuring error can be kept within acceptable limits when the frequency of the reference signal U.sub.r (t) is selected to be sufficiently high; to give an example, a doubling of this frequency reduces the measuring error to one fourth. However, due to the finite operating speeds of certain components, such as for example of the comparator, the frequency of the reference signal U.sub.r (t) can not be selected at an arbitrarily high degree.
The invention has as its object a reduction of the measuring error, without increasing the frequency of the reference signal U.sub.r (t).
By means of the method designed, according to the invention, the frequency of determining and multiplying the measuring value is doubled compared to the earlier proposal, as a result of which the measuring error is reduced to one fourth.
BRIEF DESCRIPTION OF THE DRAWING
The invention will be explained in the following in more detail by means of an example of a static electric meter for the measurement of electric energy in an alternating-current network.
FIG. 1 is a block circuit diagram of a static counter of electricity;
FIG. 2 is a voltage-time diagram applicable to the block-cir
REFERENCES:
patent: 4056775 (1977-11-01), Milkovic
patent: 4077061 (1978-02-01), Johnston et al.
patent: 4218736 (1980-08-01), Haraguchi
patent: 4240149 (1980-12-01), Fletcher et al.
patent: 4250552 (1981-02-01), Elms
Nuenlist Hans
Schneider Gernot
Steinle Benedikt
LGZ Landis & Gyr Zug AG
Marmorek Ernest F.
Wise Edward J.
LandOfFree
Method for the measuring of electrical power does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for the measuring of electrical power, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for the measuring of electrical power will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-951442