PRE-VALIDATION OF THE PROTOTYPE
Table of contents
Methodology
Results
A) At normal Temperature
B) At high Temperature
Discussion
Methodology
A pre-validation study was designed and conducted in order to assess the performance of the device. Leakage current is generated using variable current source. Table 1 Measurements of the leakage current using our device are compared with the LIMIT600 measurements voltmeter (Product reference: 5690447, Limit company, Alingsås, Sweden), which is well known and received CE Mark approval. The Limit600 was calibrated to make sure it produces accurate results. The accuracy of the current measuring device is limited by the international standard IEC601-1 (Safety requirements for electrical equipment for measurement, control and laboratory use) by the following equation:-
Accuracy = ((-+)1% ofactualcurrentreading (-+)1µA)
17 measurements with both devices were taken in the following conditions: Test 1: At normal temperature Test 2: At high temperature
Results
A) At normal temperature
Table.1 leakage current measurements values for 17 samples using our prototype and LIMIT600 at normal temperature.
As we can notice from Table 1, our prototype outperforms Limit600 in most of the current readings. For example, in current value no 1 the allowed range for the measured value is within 66.1 µA and 69.5 µA where our device and Limit600 consistent with. On the other hand, Limit600 fail to measure the current within the allowed range (red color in table 1) which is declared by IEC601-1. For detailed comparison, we plot the three current values in Fig 1 where the deviation from original current values could be detected. We could detect the sufficient accuracy our prototype has and the deviation of Limit600 from the original readings.
Fig.1.Current measured by our device and Limit600 are compared by the original current.
B) At high temperature
To test the prototype reliability we get the measurements from the current source at 70 Celsius degree temperatures (we raise the temperature using Sauna belt). Table.3 leakage current measurements values for 16 samples using our prototype and LIMIT600 at high temperature.
Discussion
The leakage current tester has been designed and constructed in this study was aimed to assess a low cost device with high accuracy and to be portable.
The results of testing are indicated that the measured value from prototype is error within the acceptable range according to the international standards.