Emergency vehicle lights

Ex volunteer and paid on call Firefighter/EMT from 1981 to 1990 here. Have just started to collect lights and sirens. Modest collection consists of a Federal Signal Beacon Ray 175, similar to one on a truck from my first department in the Southwest. Red and clear, one beam is at a 30 degree upward angle, these were nicknamed "hill light". Have a slightly later one,a Federal 184 that was made into a table lamp. And for sirens, a late 60's Federal Director similar to what we used in our ambulances.

 

The Model 175 “Hill Light” is my favorite. I have two. A 1966 vintage, glass dome, high base (black data plate) and a 1974 vintage, plastic dome, short base (red data plate). I also have a 1977 vintage Federal Signal Model 28 siren. The lights are powered by an Astron RS-50A, 50 amp AC/DC linear power supply.


Decoding the Model 175 Beacon Ray serial numbers. Produced from 1961 thru 1982.

First digit indicates voltage.
1 = 6VDC
2 = 12VDC
4 = 24VDC

The next letter indicates a range of years.
N = 1961-1962
P = 1963- early 1968
R = Late 1967-1976

The next two digits indicate the specific model of the beacon.
10 = All 175 versions except special order, "N" and "P" serials.
15 = All 175 versions except special order, "R" serial.
11, 12, 14 = Special order 175-H for the New York City Police Department, Upward tilted bulb reduced from 45* to 15* tilt.

The letter after the model likely indicates the month, the letters "I", "J", "L", and "O" are skipped.
A = January
B = February
C = March
D = April
E = May
F = June
G = July
H = August
K = September
M = October
N = November
P = December

The final digit is the last digit of the year.

So 1N10P1 is 6VDC, model 175, December, 1961.

"R" serial numbers are introduced in the middle of 1967. "R" serials for 1967 decode in the same fashion as the "P" serials.

Serial numbers beginning in 1968 are easier to decode as Federal simply stamped the year as the last two digits of the serial number.

So 2R15M71P is 12VDC, model 175, October, 1971.

During 1976, Federal ceased using serial numbers and switched to marking the 175 Beacon Ray as Series A1. During the Series A1 production, Federal exhausted their supply of the large diameter motor and switched to the motor used in the Model 24 Aerodynic. These motors are smaller in diameter and have two vent slots near the base of the motor. These motors may also have a label on them that contains the date for the motor.