scope:

This specification covers phase sequence indicators which indicate on polyphase alternating current (a.c.) circuits the order in which the voltage wave in each phase reaches its maximum positive value.

Phase sequence indicators shall be of the following types as specified (see 6.2):

Indicators covered by this specification are designated by the two-letter symbol "MR".

The style is designated by a two-digit number which signifies the size and shape as follows.

2 - 2-½ inch indicator with two indicator lamps

3 - 3-½ inch indicator with five indicator lamps

4 - 4-½ inch indicator with five indicator lamps

R - Round flange

S - Rectangular flange Beneficial comments (recommendations, additions, deletions) and any pertinent data which may be of use in improving this document should be addressed to: Commander, Naval Sea Systems Command, SEA 55Z3, Department of the Navy, Washington, DC 20362 by using the self-addressed Standardization Document Improvement Proposal (DD Form 1426) appearing at the end of this document or by letter.

B - Black dial, white lettering

W - White dial, black lettering

1 - 120 volts (V)

2 - 208 V

4 - 450 V

AC - 60 hertz (Hz)

AF - 400 Hz

AM - 25 to 1000 Hz

The unit shall be PHS for phase sequence.

intended Use:

The indicators are for determining the phase sequence of three-phase a.c. power systems.