NPFC - MIL-S-22820
SERVOMOTOR-TACHOMETER GENERATOR, AC; GENERAL SPECIFICATION FOR
|Publication Date:||28 November 1990|
This specification covers the general requirements for servomotor-tachomete
The nomenclature consists of the item name, Servomotor-Tachomete
If the servomotor-tachomete
The first two digits designate the maximum diameter in tenths of an inch of the servomotor section of the servomotor-tachomete
The succeeding two groups of letters separated by a hyphen designates the function of the servomotor and the tachometer generator sections, respectively, in accordance with the following code:
First two-letter group Function SM Servomotor Second two-letter group Function DG Damping Tachometer Generator RG Rate Tachometer Generator IH Integrating Tachometer Generator, Heater Compensated IN Integrating Tachometer Generator, Network Compensated
The succeeding digit indicates the design frequency of the servomotor section of the servomotor-tachomete
Frequency Code 60 6 400 4
An upper case letter "A" (in the illustration) following the frequency digit indicates the basic issue of a standard servomotor-tachomete
The part identifying number (PIN) should consist of the letter "M", the basic number of the specification sheet (not including the revision letter), an assigned dash number and an upper case suffix letter denoting the latest modification letter in the type designation, as shown in Table II.
All standard servomotor-tachomete
Ideal characteristics of all tachometer generators include low inertia rotors, high output-to-null ratios, a strictly linear relationship of output voltage as a function of rotor speed over a broad range of ambient temperatures, and a minimum phase shift between the fundamental output and input voltages. The maximum degree to which any one of the ideal characteristics is achieved is often at the expense of the remaining. General practice is to group tachometer generators in accordance with their anticipated application.
Tachometer generators in this group are characterized by high theoretical stall acceleration figures and low null output, and are employed to stabilize the parent system.
A rate tachometer generator is a generator characterized by a relatively high output-to-null ratio, and as such, is employed in high-gain rate and computing servomechanism applications. The rotor is of relatively low moment of inertia. Such applications require a high degree of linearity over the range of speeds of the generator.
An integrating tachometer generator is a generator used in computing applications requiring integration of a variable with respect to time. This type of tachometer generator is characterized by very small deviations of the output voltage as a function of temperature and a minimum warm-up time. Temperature control and compensation networks are usually integral parts of integrating generators.
The intended use for servomotor-tachomete