IEC 60051-5:1985 pdf free download.Direct acting indicating analogue electrical measuring instruments and their accessories – Part 5: Special requirements for phase meters, power factor meters and synchroscopes.
1.1 Part 5 of this standard applies to direct acting indicating analogue phase meters, power factor meters and synchroscopes.
1.2 This part also applies to non-interchangeable accessories(as defined in Sub-clause 2.1.15.3 of Part 1)
used with phase meters, power factor meters and synchroscopes.
1.3 This part also applies to a phase meter or power factor meter whose scale marks do not correspond directly to its electrical input quantity, provided that the relationship between them is known.
4.1.2 See Part 1.
4.1.3 Reference conditions different from those given in Tables I-i and 1-5 may be specified, but they shall then be marked in accordance with Clause 8 of Part 1.
4.2 Li,nit.c of intrinsic error, fiducial value See Part 1.
For a synchroscopc, the accuracy rcquircmcnts apply only at the synchronizing mark.
4.2.1 Correspondence between intrinsic error and accuracy class See Part 1.
4.2.2 Fiducial value
The fiducial value corresponds to 90 electrical degrees.
Thc class index is marked using Symbol E-1 given in Table HI-i of Part 1 (see Part 1, Clause 8).