Decree No. 71 / 2004 Coll.
Order setting out requirements for measurement assemblies with Epstein apparatus for measuring magnetic properties of sheets for electrical equipment
Valid
Effective from 01.03.2004
71
DECLARATION
of 3 February 2004
laying down requirements for measuring assemblies with Epstein apparatus for measuring magnetic properties of sheets for electrical equipment
The Ministry of Industry and Trade provides pursuant to Section 27 of Act No. 505 / 1990 Coll., on Metrology, as amended by Act No. 119 / 2000 Coll. and Act No. 137 / 2002 Coll., ("the Act") for the implementation of Sections 6 (2) and 9 (1) of the Act:
This Decree sets out the requirements for measurement kits with Epstein apparatus for measuring the magnetic properties of electrical sheet metal (hereinafter referred to as the "measuring assemblies'), the procedure for approving them and the procedure for verifying them.
The terminology, the requirements for metering assemblies as well as the procedure for type-approval of metering assemblies and their verification procedure are set out in the Annex.
This Decree shall take effect on 1 March 2004.
Minister:
Ing. Urban v. r.
Annex to Decree No 71 / 2004 Coll.
1 TERMINOLOGY
1.1 The measurement assembly is used for measuring amplitude characteristics and specific loss of sheets for electrical equipment. It shall consist of instruments and devices connected to images 1 to 3 and specified in paragraph 2.
1.2 An ethallic sample for Epstein's measuring kit is a sample meeting the requirements of this decree and used exclusively for the metrological continuity of the measurement assembly.
1.3 The etalon measurement set-up is the measurement set-up referred to in point 1.1, which is held by the metrology institution, is monitored over a long period of time and is internationally compared through ethalon samples.
1.4. The measured losses measured by the measurement assembly are losses by re-magnetisation in the measured sample relative to the active mass of the sample.
1.5 The amplitude characteristic is the dependence of the magnetic polarisation amplitude in the sample on the magnetic field amplitude in the sample.
2 REQUIREMENTS FOR MEASURING CONTRACTS
2.1. METHOLOGICAL REQUIREMENTS
The measurement assembly shall consist of parts which must meet the following requirements:
(a) Epstein's apparatus as specified in 2.2;
(b) a frequency gauge measuring with an error of 0,1% or less;
(c) a mean voltmeter measuring with an error of 0,2% or less;
d) an effective voltmeter measuring with an error of 0,2% or less;
(e) a power meter measuring with an error of 0,5% or less at the current power factor and crest, the voltage circuit resistance of the power meter shall be at least 5000 times greater than its reactants;
(f) a voltmeter of amplitude measuring with an error of 0,5% or less in conjunction with a resistance with a compliant current and a value known with an error of 0,2% or less (instead of a voltmeter of amplitude with a resistance, mutual inductance may be used with a compliant current in the primary winding and a value known with an error of 0,2% or less with a two-pole switch and a mean voltmeter);
(g) the source of the magnetic current with low output impedance and high voltage and frequency stability, voltage and frequency fluctuations shall not exceed 0,2% of the value used. For measuring specific losses, a secondary voltage factor of 1,111 ± 1 per cent shall be provided.
The measurement assembly shall include follow-up etalon samples which shall correspond to the magnetic properties and mass of samples normally measured by the measurement assembly. These samples shall comply with the relevant requirements of paragraph 2.2.
2.2 TECHNICAL REQUIREMENTS
2.2.1. Construction
2.2.1.1 Epstein apparatus
The Epstein apparatus consists of four coils in which the tapes of the test sample of the electroplate are inserted. The coils are made of hard insulating material, they have a rectangular cross section with an inner width of 32 mm. Recommended internal height is 10 mm. The coils are mounted on an insulating and non-magnetic plate by forming a square. The length of the side of the square of the inner edges of the band inserted is 220 + 1 -0 mm.
Each coil has two winding - external primary winding and internal secondary winding. There may be electrostatic shielding between them. The winding shall be wound evenly over a length of 190 mm, each coil having one quarter of the total number of turns. The primary winding of all coils is serial, as well as the secondary winding of all coils is serial. The number of turns is not prescribed, but usually 700 for use at a frequency of 50 Hz.
In order to reduce the impact of the impedance of winding, the following impedance shall meet the following conditions:
R1 / N12 ≤ 1,25.10- 6, R2 / N22 ≤ 5.10- 6, (1)
L1 / N12 ≤ 2,5.10- 9 H, L2 / N22 ≤ 2,5.10- 9 H, (2)
where R1 and R2 are the resistance of the primary or secondary winding,
L1 and L2 are induction of primary or secondary winding,
N1 and N2 are the total number of turns of primary and secondary winding.
The Epstein apparatus must be compensated for by air magnetic flux. For this purpose, a coil of mutual inductance is placed in the middle of the space enclosed by the coils of Epstein's apparatus, its axis perpendicular to the plane formed by the axes of the coil of Epstein's apparatus. The primary winding of this compensation coil is connected in series with the primary winding of the Epstein device and the secondary winding is connected in series with the secondary winding of the Epstein device so that the induced voltage in these secondary winding is the opposite polarity. The setting of the value of compensation inductance is such that the voltage measured between the free unconnected ends of the secondary winding is not greater than 0,1% of the voltage on the secondary winding of the uncompensated Epstein apparatus when passing through the alternating current by the primary winding at the empty Epstein device (sample not inserted).
2.2.1.2 Etalon samples
The measurement assembly shall include etalon samples for the Epstein apparatus (hereinafter "etalon samples'). These samples shall cover the range of magnetic properties and the mass of samples normally measured by the measurement assembly.
Etalon samples are made of electrical steel. The tapes of the etalon sample shall be flat, cut without visible bursts and uneven edges and, if specified, heat treated. The tapes shall be clean, free of rags and other impurities. The sample strips shall have the following dimensions:
a width of 30 ± 0,2 mm, length greater than or equal to 280 mm and less than or equal to 320 mm.
The length of the strips shall be the same with a tolerance of ± 0,5 mm. When the tapes are cut parallel or perpendicular to the rolling direction, the edges of the belt or pane are taken as a reference direction. Sample strips made of oriented material shall have the direction of the longer axis of the tape different from the direction of rolling by a maximum of ± 10. In the case of samples made of unoriented material, half of the strips shall have a direction of a longer axis equal to the direction of rolling with a tolerance of not more than ± 50 and the other half shall have a direction of a longer axis perpendicular to the direction of rolling with a tolerance of not more than ± 50. Each tape shall show the direction of rolling. The longer axis bands in the direction of rolling shall be inserted into the opposite parallel coils of the Epstein apparatus and the longer axis bands perpendicular to the direction of rolling shall be inserted into the remaining coils.
The number of tapes of the sample is divisible by four. The active mass of the etalon sample shall be at least 240 g for samples of 280 mm long.
The effective length of the magnetic circuit of the lm sample is determined by agreement 0,94 m. The active mass of the sample ma is given by the relationship
ma = m.lm / 4l, (3)
where
l is the length of the sample tape in m,
lm is the effective length of the magnetic circuit 0,94 m,
m is the total weight of the sample in kg,
ma is the active sample weight in kg.
2.2.1.3 Measurement set-up
2.2.1.3.1. Measurement set for measuring specific losses
The measurement set for measuring specific melting is connected according to the diagram in Figure 1. The magnet current is slowly increased up to the required mean value of the directional voltage of VV124; U2m VV124; on the secondary winding of the Epstein device. The ampermeter shall be monitored for the value of the magnetic current so that the wattmeter current circuit is not overloaded. The mean voltage value is calculated from the required magnetic polarisation amplitude according to:
U2m = 4-N2AJaRi / Ri + Rt, (4)
where
VY124; U2m VY124; is the mean value of the directional voltage induced in the secondary winding in V;
This is the frequency in Hz,
N2 is the total number of turns of secondary winding,
A is the cross-section of the sample in m2,
I'm the amplitude of magnetic polarization in T,
Ri is the overall resistance of the apparatus in the secondary circuit,
Rt is the sum of the secondary winding resistance of the Epstein apparatus and the compensation of mutual inductance,
The cross-section of the sample is calculated from the equation
A = m / (4l ρm), (5)
where
And is the cross-section of the sample in square meters,
m is the total weight of the sample in kg,
l is the length of the sample strips in m,
ρm is the determined sample material density in kg / m3.
Figure 1
The amplitude in the primary circuit is shortened and the voltage is then equal to the required value. The ratio of the mean value and the effective value of the induced voltage shall be determined by the induced voltage shape factor, which shall be 1,111 ± 1 per cent.
The total losses of Pc shall be calculated from the wattmeter data according to:
Pc = Pm N1 / N2- (1,111 Mt 124; U2m Mt 124;) 2 / Ri, (6)
where
Pc are the total calculated losses of the sample in W,
Pm is the power measured by the wattmeter in W,
N1 is the total number of turns of the primary winding,
N2 is the total number of turns of secondary winding
Ri is the total equivalent resistance of the apparatus in the secondary circumference of,
VV124; U2m V124; is the mean value of the directional voltage induced in the secondary winding in V.
Ps shall be calculated according to the relationship
Ps = Pc / ma = Pc / ma.4l / lm, (7)
where
Dogs are the total specific loss of the sample in W / kg,
l is the length of the sample tape in m,
lm is the contracted effective length of the magnetic circuit in m (lm = 0,94 m),
m is the total weight of the sample in kg,
ma is the active weight of the sample in kg,
Pc are calculated total losses of the sample in W.
2.2.1.3.2. Measurement set for amplitude measurement
The measurement set for measuring amplitude characteristics is connected according to the diagram in Figure 2 or Figure 3. Before measuring the amplitude characteristics, the sample shall be unmagnetised by setting an alternating magnetic current corresponding to the saturated magnetic polarisation in the sample and reducing it slowly to zero.
Magnetic polarisation amplitude The Ja is determined by measuring the mean value of the directional voltage induced in the secondary winding according to the relationship (4).
The amplitude of the magnetic field in sample Ha is determined by measuring the amplitude of the current in the circuit of the primary winding I1a, this is the measurement of the voltage amplitude of U1a on the resistance R in connection as shown in Figure 1. I1a = U1a / R. The amplitude of the magnetic field intensity is calculated from the equation:
Ha = I1aN1 / lm, (8)
where
Ha is the amplitude of the magnetic field intensity in the sample,
I1a is the amplitude of the magnetic current in the primary winding circuit
Im contracted effective length of the magnetic circuit of the sample
N1 is the total number of turns of the primary winding of the Epstein apparatus
Figure 2
Alternatively, the amplitude of the magnetic field may be determined by measuring the mean value of the directional voltage induced in the secondary winding of the mutual inductance MD, the primary winding of which is connected in the series with the primary winding of the Epstein apparatus in connection according to the diagram in Figure 3. When using this method, it is necessary to check the shape of the time course of the UDm oscilloscope, the time course must have only two passes of zero during one period. A voltmeter measuring the secondary voltage of Epstein's apparatus and a switch as shown in Figure 3 may be used as the mean voltmeter required to measure UDm.
The magnetic field intensity amplitude shall be calculated from the equation:
Ha = UDmN1 / 4-MDlm.Rv + Rm / Rv, (9)
where
MD is the mutual inductance in the circuit according to Figure 3 in H
Rv is the internal resistance of the voltmeter of the mean value in ∞,
Rm is the resistance of secondary winding of mutual inductance of MD v ∞,
UDm is the mean value of the directed voltage induced in the secondary MD winding.
Figure 3
2.2.2. Labels and marks
2.2.2.1 Measurement set-up
The special inscriptions and marks on the measurement set-up shall be replaced by technical documentation which shall be drawn up and shall include:
(a) a list of all measuring instruments and equipment belonging to the measurement assembly, indicating the manufacturers and production numbers and, where appropriate, the errors of measuring instruments and measuring kits as specified by the manufacturer;
(b) a detailed and clear diagram of the connection for the relevant type of measurement, technical descriptions and instructions for operation of the components of the measurement assembly;
(c) brief descriptions of the measurement and power methods (for example, power supply by an amplifier forcing the sinus time course of magnetic induction, power measurement by the converter based on the sampling principle, use of the control computer),
(d) the lower and upper limits of the ranges in which the measurement assembly will be used;
(e) impedance of important components and gauges;
(f) a list of etalon samples;
(g) calibration or verification sheets of measuring instruments which are part of the measurement assembly, if calibration or verification has been carried out;
(h) the verification sheet of the measurement report in subsequent verification;
(i) a record of all measurements with etalon samples relating to the measurement assembly.
2.2.2.2 Epstein apparatus
The coils of the Epstein apparatus shall be marked. A, B, C, D. The number of turns of primary and secondary winding shall be indicated on the Epstein apparatus and in the documentation of the measurement assembly.
2.2.2.3 Etalon samples
The etalon sample shall bear the registration number or letters, in the same, permanent and indelible manner, on each patch of the etalon sample.
All tapes of an etalon sample shall be marked in such a way that their composition in the Epstein apparatus is possible in a single way.
Each etalon sample shall be accompanied by a record sheet indicating:
(a) the registration of the ethalon sample;
(b) the type and type of material;
(c) cross-section of the sample,
(d) sample density,
(e) the weight of the sample,
(f) the number of tapes of the sample,
(g) the thickness, width and length of the tapes of the sample.
If all the data to be included in the record sheet are included in the sample calibration sheet, the etalon sample may not have a record sheet.
3. APPROVAL
3.1. Type-approval procedure
3.1.1 Preliminary assessment
The evaluating authority shall, on the basis of the examination of the documents1) ascertain whether the documentation and then the measuring assembly comply with the requirements of this Decree, decide on the continuation of the tests or submit a proposal for a negative termination of the tests.
3.1.2. Preliminary test by measuring material samples
3.1.2.1. The applicant shall deliver to the evaluating authority at least 2 pieces of etalon samples belonging to the test set. These samples shall cover their mass and their magnetic characteristics the range of mass and the magnetic characteristics of the samples measured by the test set within the test type. These etalon samples shall comply with the requirements of paragraphs 2.2.1.2 and 2.2.2.3. The applicant's etalon samples shall be accompanied by a copy of the sample records, where appropriate, of the previous sample verifications. The samples delivered shall be accompanied by the results and reports of their measurements by a test set in the range of tests carried out not more than 3 months before the date of delivery.
3.1.2.2. In the case of samples delivered, the specific losses and amplitude characteristics referred to in paragraph 2.2.1.3 shall be measured on the measuring kit of the assessment body. A verification sheet shall be issued for the measured sample, indicating the arithmetic mean values from repeated measurements.
3.1.2.3. The relative differences between the measurement of specific losses of etalon samples (related to the test set) by the test set and the etalon set in% shall be calculated.
δpi = (pli-p2i) .100 / p2i, (10)
where p1i is the arithmetic centre of measurement of the ith value of specific losses by the test set (results of measurements sent from the applicant together with etalon samples),
p2i is the arithmetic centre of measurement of the ith value of the specific losses by an etalon measurement set (the results of the measurements given in the calibration sheet).
The relative differences between the specific losses of δpi recorded in this test shall be less than 3% for samples of the oriented material for magnetic polarisation values up to 1,7 T and for samples of the unoriented material for magnetic polarisation values up to 1,5 T.
3.1.2.4. The relative differences between the measurement of the amplitude characteristics of the etalon samples (belonging to the test metering set) by the test metering set and the etalon metering set in% shall be calculated as the minimum standard distance of the ith point (Bi, Hi), the characteristics determined by measuring the measured metering set from the characteristic determined by measuring the same etalon sample by the etalon metering set according to the equation (11), (12) or (13):
δai = δBi.100 / --1 + Hi / Bi.dB / dHi2 =
= IUPAC Name
δai = δHi.100 / --1 + Bi / Hi.dB / dHi-12 =
(12)
δai = δBi.δHi.100 / --δBi2 + δHi2 =
(13)
where the square roots are taken only positive and where
(14)
IUPAC Name
δHi = (Hi -Hi ') / ZV124; Hi ZV124;
(17)
(dB / dH) i is the slope of the tangent curve given by measuring the etalon sample by the etalon measurement set at the point (Hi, Bi '),
Hi and Bi are the intensity values of the magnetic field or magnetic induction of the ith point, respectively, the characteristics of the etalon sample measured by the measured measurement set,
Bi 'is the magnetic induction value subtracted from the characteristic measured by the etalon measurement set for the Hi value,
Hi 'is the magnetic field intensity value subtracted from the characteristics measured by the etalon measurement set for the Bi value.
The relative variation in the measurement of the amplitude characteristic of δai shall be less than 4% for all measurement points of the characteristics of the etalon samples within this test.
3.1.3. Inspection of the test metering assembly
The external inspection and inspection of the prescribed technical documentation shall take place at the point of use of the test metering assembly. The external inspection shall check:
(a) the measuring assembly shall not be mechanically damaged;
(b) the measurement assembly shall consist of measuring instruments, etalons and components specified in the documentation;
(c) the arrangement of measuring instruments and components shall be in accordance with the wiring diagram for the relevant type of measurement;
(d) the completeness of all documents required under point 2.2.2.
3.1.4 Test by measuring material samples
The measurement of the samples shall be carried out by measuring the etalon samples (belonging to the etalon metering assembly) of the testing metrological authority in its presence by the test metering set in accordance with paragraph 3.1.2.
3.1.5 Drawing up of the technical test report
The test report shall contain a description and results of the tests carried out in accordance with paragraphs 3.1.2, 3.1.3 and 3.1.4, which shall have a positive result. It also contains descriptions, drawings and diagrams necessary to identify the type and clarify its function.
3.2. Type-approval certificate
The particulars of the type-approval certificate shall be laid down in a separate legislative act (2).
4. VERIFICATION
Initial and subsequent verification shall consist of tests according to paragraphs 3.1.2, 3.1.3 and 3.1.4. If the result of all these tests is positive and the measurement set-up meets the requirements laid down in this Regulation, a verification sheet shall be issued and the test set-up shall be provided with an official mark (3).
1) Paragraph 1 (2) of Decree No. 262 / 2000 Coll., which ensures consistency and accuracy of measuring and measuring instruments, as amended by Decree No. 344 / 2002 Coll.
2) § 3 of Decree No. 262 / 2000 Coll.
3) § 6 of Decree No. 262 / 2000 Coll.
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Regulation Information
| Citation | Decree No. 71 / 2004 Coll., laying down requirements for measuring assemblies with Epstein apparatus for measuring magnetic properties of sheets for electrical equipment |
|---|---|
| Regulation Type | - |
| Author | - |
| Collection | Code of Laws |
| Date of Promulgation | 24.02.2004 |
|---|---|
| Effective from | 01.03.2004 |
| Effective until | - |
| Status | Valid |
The regulation text is for informational purposes only.
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