scope:

This Defence Standard relates to Two-phase Tachometer-Generators ac, hereinafter referred to as tachometer-generators. It is not complete in itself but shall be read in conjunction with Defence Standard 61-14 (PART 1), 'Standardization of general requirements and common tests for precision instrument rotating servo-components', hereinafter referred to as DEF STAN 61-14 (PART 1); in which the latter shall be regarded as forming an inherent part of this document.

The Standard gives information on or states the requirements for those attributes which are relevant to tachometer-generators:

- Definitions, terms and conventions

- Type designations and marking

- Test requirements and methods of test

- Nature of test equipment.

Physical and performance requirements for individual types of standard tachometer-generators are given in the relevant Supplementary Detail Sheets associated with this Standard.

Note: Performance figures and their limits stated in the relevant Supplementary Detail Sheet are based on a close-tolerance power supply a~d on test conditions which are strictly controlled. Under Service conditions these figures may be modified by the effects of power supply variations and of environmental conditions.