scope:

This specification covers variable resistors having a composition resistance element shaped in an arc, and a contact bearing uniformly thereon, so that a change in resistance is produced between the terminal of the contact and the terminal of either end of the resistance element when the operating shaft is turned. These resistors are capable of full load operation (where maximum resistance is engaged) at a maximum ambient temperature of 70°C, and are suitable for continuous operation when properly derated, at a maximum temperature of 120°C (see 6.8).

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

The style is identified by the two letter symbol "RV" followed by a one-digit number. The letters identify composition, variable resistors and the number identifies the size and power rating.

The type of bushing is identified by a single letter in accordance with table I. TABLE I. Bushing.

Symbol Bushing. ------------------------------------------- N Standard L Locking S Shaft and panel-sealed (standard) T Shaft and panel sealed (locking)

Beneficial comments (recommendations, additions, deletions) and any pertinent data which may be of use in improving this document should be addressed to: Commander, US Amy Laboratory Command, (LABCOM), ATTN: SLCET-RS, Fort Monmouth, NJ 07703-5000 by using the Standardization Document Improvement Proposal (DD Form 1426) appearing at the end of this document or by letter.

The type of switch or absence of a switch is identified by a single letter in accordance with table II. TABLE II. Switch.

Symbol Bushing ----------------------------------------- A No Switch B Single pole, single throw switch which is actuated to the "on" position at the start of clockwise rotation 1/ For replacement purposes only. Not to be used for new design.

The temperature and moisture resistance characteristic is identified by a single letter in accordance with table III. TABLE III. Temperature and Moisture resistance characteristic.

Symbol Maximum Maximum Allowable change in Insulation ambient ambient total resistance due resistance operating temperature to moisture resistance (see 4.6.4) temperature at rated (see 4.6.10) wattage Maximum --------------------------------------------------------------------------- Y °C °C Percent Megohms 120 70 10 100

The operating shaft styles and lengths are identified by a two digit symbol. The first letter indicates operating shaft in accordance with table IV, and the second letter indicates operating shaft length, as specified (see 3.1). TABLE IV. Style of operating shaft.

Symbol Shaft ---------------------- F Slotted S Flatted

The nominal total resistance value expressed in ohms is identified by a three digit number. The first two digits represent significant figures and the last specified the number of zeros to follow.

The resistance characteristic is identified by a single letter in accordance with table V. TABLE V. Resistance characteristic.

Symbol. Resistance taper Resistance (see figures 3 and 4) tolerance ------------------------------------------------- Percent (±) A A 10 B A 20 C C 10 D C 20 E F 10 F F 20

The PIN RV2NAYSD103A signifies:

RV2 - A composition, variable resistor of the dimensions and power rating specified (see 3.1). N - Standard bushing. A - No switch. Y - Temperature and moisture resistance characteristic as specified in table III. SD - Slotted shaft .875 inch long. 103 - Nominal total resistance value of 10,000 ohms. A - Linear taper with resistance tolerance of ±10 percent.

intended Use: