CD V-750 Dosimeter Chargers (ca. 1954 - 1964)

The primary purpose of the Model CD V-750 was to charge civil defense dosimeters (CD V-138, 730, 740, and 742). By charge, we mean adjust the dosimeter so that the quartz fiber, visible through the eyepiece as a fine line running vertically across the scale,  is set at zero.  The CD V-750 could also be used to read the dosimeters if insufficient light was available - quite possible in an emergency situation.

The key features of the CD V-750 were the charging contact (protected by a dust cap attached to the case via a bead chain) and the control knob for adjusting the charge.

The Bendix charger Model 643 shown to the right is extremely early (ca.1954 - 1956). While it is identified as a CD V-750, there is no model number. Nevertheless, it was referred to by the OCDM as the CD V-750 Model 1.  

What is most interesting is the the fact that the push lever towards the lower left is used to provide the charge. The mechanical energy generated by pumping the lever is converted into electrical energy. The unit does employ a battery, but only to power the light used to illuminate the dosimeter scale. 

The case is relatively large (4.5" x 4.5" x 2.5") because it has a storage location for the battery when the unit is not being used. 

The Bendix Model 1 was donated by the Federal Emergency Management Agency courtesy of Carl Siebentritt

Bendix CD V-750 Model 1 (above)

 

 

 

The Jordan Electronics, Inc. charger shown to the right is identified as a CD V-750. While there is no model number on it, the OCDM referred to it as the CD V-750 Model 2.  

 

 

 

Donated by William Bashaw III

Jordan Electronics CD V-750 Model 2 (above)

 

 

The Universal Atomics Model 3 in the photograph to the right is a transistorized version of the 750. The case (ca. 4.5" x 4.5" x 2") is plastic. Since a Universal Atomics Model 3 with a later serial number appears in the Civil Defense Technical Bulletin TB-11-20 (revised June 1959), it is probably safe to say that this example dates from 1957-1959.  Since the Model 3 was also referred to in a January 8, 1959 OCDM Advisory Bulletin, it is safe to say that the Model 3 came along in 1957 or 1958.  The manufacturer, Universal Atomics Corp., also made a commercial version, the UAC 750.

Universal Atomics CD V-750 Model 3 (above)

 

 

 

In September 1954, FEMA sent a notification to the maintenance and calibration facilities indicating that Models 1 - 3 of the CD V-750 were obsolete.

 

 

The Model 3, but not the Model 4, was  referred to in a January 8, 1959 OCDM Advisory Bulletin.  As such, the Model 4, if it existed, probably made its first appearance in 1959 or 1960.

Jordan Electronics CD V-750 Model 5 (above)

 

 

 

 

Batteries: one 1.5 volt "D cell" 

Manufacturers: Bendix Aviation Corp., Jordan Electronics, Universal Atomics, Industrial Electronic Hardware Corp.

Models: 1, 2, 3, 4, 5, 5a, 5b (the Model 6 is treated separately)

Number Produced: approximately 515,000

 

 

Jordan Electronics CD V-750 Model 5a (above)

 

Jordan Electronics CD V-750 Model 5b (above)

The photograph above left shows a CD V-750 Model 5b produced by Industrial Electronic Hardware Corporation, probably the most commonly encountered version of the CD V-750.  The photo above right shows a Jordan Electronics CD V-750 Model 5b with a serial number of 001 stamped on the case. 

Estimated Dates of First Production:  Model 1   ca. 1955

                                                               Model 2   ca. 1956

                                                               Model 3   ca. 1957, 1958

                                                               Model 4   ?

                                                               Model 5    ca. 1960

                                                               Model 5a    ca. 1961

                                                               Model 5b  ca. 1962

Approximate Cumulative Procurement, Inventory and Distribution of CD V-750s*
Fiscal Year Procured Inventoried  Distributed
Through FY 1956 2,395   992
FY 1957 16,524   6561
FY 1958 38,609   17,743
FY 1959 38,937 9,138 29,799
FY 1960 38,937 1,134  
FY 1961 137,703 95,958 41,745
FY 1962   122,672 59,247
FY 1963 515,032    
FY 1964 515,032    
FY 1965 515,032 264,196 249,096
FY 1966 515,032 227,803 287,218
FY 1967 515,032 209,188 305,831
FY 1968 515,032 183,265 331,699
FY 1969 515,032 162,571 352,374
FY 1970 515,032 136,956 378,423
FY 1971 515,032 122,593 392,402
FY 1972 515,032 112,154 402,838
FY 1973      
FY 1974 515,032 17,220 497,772

*  The numbers in the above table should be considered approximate. I compiled them from data in the Annual Statistical Reports of the OCDM, OCD and DCPA. By "procured," I mean delivered by the manufacturer to the OCDM, OCD or DCPA. "Inventoried" means stored in a Federal (rather than state) warehouse available for distribution. "Distributed" means sent to the end user. The latter primarily means the states, but also various federal agencies and even foreign governments. The number of procured instruments may be greater than the combined number of inventoried and distributed instruments for a variety of reasons: some may have been sent back to the manufacturer, some may have been disposed of, the numbers might be incorrect, etc.

References

Civil Defense Technical Bulletin TB-11-20 Radiological Instruments for Civil Defense September 1955 (Revised June 1959).

Office of Civil and Defense Mobilization. Interim Procedures for Maintenance of Radiological Instruments. Advisory Bulletin No. 229. January 8, 1959.

Operating and Maintenance Instructions for the Jordan Model 750-5 Dosimeter Charger, no date.

FEMA, Radiological Instruments: An Essential Resource for National Preparedness, CPG 3-1/September1986.

Museum Directory        Civil Defense

Last updated: 05/24/11
Copyright 1999, Oak Ridge Associated Universities