scope:

This specification covers the general requirements for watertight, ruggedized, 1- and 1-½-inch square flange, 1-, 2-½-, 3-½-, and 4-½-inch round flange (flush mounting), and 4-½- and 5-½-inch rectangular flange, panel type, indicating meters (see 6.1).

Meters, all self-contained unless otherwise specified (see 3.1), covered by this specification shall be of the following types:

(a) 1-inch, direct current, millivoltmeters, microammeters, milliammeters, ammeters, and voltmeters.

(b) 1-½-inch direct current, ammeters and voltmeters.

(c) 2-½-inch and 3-½-inch, direct current, alternating current meters.

(d) 2-½-inch and 3-½-inch, alternating current, rectifier type voltmeters.

(e) 3-½-inch decibel meters.

(f) 4-½-inch, direct current meters.

(g) 5-½-inch, direct current meters.

The specified sizes, shapes of flanges, color schemes, ranges, kinds of current, and electrical units are indicated in the type designation (see 1.2.2). Unless otherwise specified, each meter shall be scaled and calibrated for use on both ferrous and non-ferrous panels.

The type designation shall be in the following form, and as specified (see 3.1 and 6.2):

No space shall appear between the groups of letters and numbers comprising the type designation.

The style is identified by the two-letter symbol "MR" followed by a two-digit number; the number signifies the size of the meter and shape of the flange.

The first digit identifies the nominal size of the meter, as follows:

0 - - - - - - - - - - - 1-inch. 1 - - - - - - - - - - - 1-½-inch. 2 - - - - - - - - - - - 2-½-inch. 3 - - - - - - - - - - - 3-½-inch. 4 - - - - - - - - - - - 4-½-inch. 5 - - - - - - - - - - - 5-½-inch.

The second digit identifies the shape of flange, and degree of enclosure, as follows:

2 - - - - - - - - Rectangular flange, watertight. 3 - - - - - - - - Square flange, watertight. 4 - - - - - - - - Round flange, watertight, long scale. 5 - - - - - - - - Round flange, watertight (for nonferrous panels). 6 - - - - - - - - Round flange, watertight (for both ferrous and non- ferrous panels). ^1/7 - - - - - - - - Round flange, watertight (for ferrous panels).

The color scheme of the dial background and of the markings and pointer is identified by a single letter, as follows:

A - - - - - - - - Additional or other dial markings such as a colored line at a particular reading, or a colored segment or segments on the dial embracing two or more readings, etc. B - - - - - - - - Black dial background; white markings and pointer. F - - - - - - - - Fluorescent (yellow) markings and pointer; black dial back- ground. M - - - - - - - - Multicolored markings. Color of the dial background and of the markings and pointer shall be as specified (see 3.1). P - - - - - - - - Phosphorescent markings and pointer; black dial background W - - - - - - - - White dial background; black markings and pointer. Y - - - - - - - - Buff dial background; black markings and pointer.

The full-scale value for meters with zero at left is identified by three digits designating the units indicated. When the full scale is less than three digits, zeros are inserted at the left to fill out to three digits. Where the letter "R" is used in this group between two digits, it represents a decimal point.

Example: 1R5 represents 1.5.

The full-scale value of offset-zero meters, including zero-center meters, is identified by two digits with a letter between, which gives the decimal value of the digits, as follows:

D - - - - - - - - Tenths. H - - - - - - - - Hundreds. T - - - - - - - - Tens. U - - - - - - - - Units.

Example: 5H5 represents 500-0-500.

The kind of current for which the meter is designed is identified by two letters, as follows:

AC - - - - - - - - -Alternating current (60 hertz (Hz), nominal frequency; 25 to 125 Hz, operating frequency), of the iron vane type only. AE - - - - - - - - -Alternating current (800 Hz, nominal frequency), of the iron vane type only. AF - - - - - - - - -Alternating current (400 Hz, nominal frequency), of the iron vane type only. AR - - - - - - - - -Alternating current sine wave (60 to 1,000 Hz), rectifier type. DC - - - - - - - - -Direct current.

The electrical unit indicated by the meter is identified by two letters, as follows:

AA - - - - - - - - Amperes. DB - - - - - - - - Decibels. KA - - - - - - - - Kiloamperes. KV - - - - - - - - Kilovolts. MA - - - - - - - - Milliamperes. MV - - - - - - - - Millivolts. UA - - - - - - - - Microamperes. VV - - - - - - - - Volts.

The letter "R" designates that the meter is of ruggedized construction.

The four letters "SPEC" are used in place of the letters specified in 1.2.2.4 and 1.2.2.5 for meters having special features, such as adjusted resistance, special scale marks, etc. These meters are assigned identifying numbers by the Defense Electronics Supply Center.

intended Use: