IEC 60851-2-2019 pdf download.Winding wires – Test methods – Part 5: Electrical properties.
This part of IEC 60851 specifies the following tests:
– Test 5: Electrical resistance;
– Test 1 3: Breakdown voltage;
– Test 1 4: Continuity of insulation;
– Test 1 9: Dielectric dissipation factor;
– Test 23: Pin hole.
For definitions, general notes on methods of test and the complete series of methods of test for winding wires, see IEC 60851 -1 .
2 Normative references
The following referenced documents are indispensable for the application of this document.
For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
IEC 60851 -1 , Winding wires – Test methods – Part 1: General
3 Test 5: Electrical resistance
Electrical resistance is the d.c. resistance at 20 °C of 1 m of wire.
The method used shall provide a precision of 0,5 %.
For bunched wires a length of up to 1 0 m shall be used and the ends shall be soldered before the measurement. When measuring the resistance to check for an excessive number of broken wires, a length of 1 0 m of bunched wire shall be used.
where
t is the actual temperature in degrees Celsius during the measurement;
α is the temperature coefficient in K –1 .
4 Test 13: Breakdown voltage
4.1 Principle
The test voltage shall be an a.c. voltage of 50 Hz or 60 Hz nominal frequency. The test voltage shall be applied at zero and increased at a uniform rate according to Table 1 .
4.2 Equipment
The following equipment shall be used:
– test transformer with a rated power of at least 500 VA providing an a.c. voltage of an undistorted sine waveform under test conditions, with a peak factor being within the limits of 2 ± 5 % (1 ,34 to 1 ,48) and with a capacity to supply a current of 5 mA with a maximum voltage drop of 2 %;
– fault detection circuit, which operates at a current of 5 mA or more;
– arrangement to provide a uniform rise of the test voltage at the specified rate;
– oven with forced air circulation;
– polished metal cylinder, 25 mm ± 1 mm in diameter, mounted with its axis horizontal (see Figure 1 ) and electrically connected to one terminal of the test voltage supply;
– twisting device according to Figure 2, that allows to twist two pieces of wire for a length of 1 25 mm;
– strips of metal foil, 6 mm in width and pressure sensitive tape, 1 2 mm in width;
– container with metal shot of stainless steel or nickel-plated iron. The diameter of the shot shall not exceed 2 mm. The shot shall be cleaned periodically by suitable means;
– metal mandrel, 50 mm ± 2 mm in diameter;
– metal mandrel, 25 mm ± 1 mm in diameter;
– metal mandrel, 80 mm ± 3 mm in diameter.IEC 60851-2 pdf download.