A Capacitor Discharge Squib Firing Unit
Abstract
In 1973, Wentworth Institute (WI) was asked to produce a practical, reliable, off-the-shelf CD unit for firing standard squibs. Design objectives included simultaneous four-bridgewire firing capability, one-second recovery, 0. 5A supply drain, and three outputs. A +28 VDC supply is required. The Model CD- B is described: a +28 volt firing command closes a selected firing relay for 30 ms; at 20 ms, the firing capacitors are discharged into the squib circuit through an SCR. The unit includes standard safety features (ARM/SAFE relay and 100 k-ohm squib isolation), and monitors for both capacitor voltage and squib current. Nine CD units have been built by WI for use in sounding rockets. Four flights have used the CD units for primary squib ignition; no malfunctions have been indicated. CD squib current data is shown for eight in-flight firings. This data suggests that a reduction in the size of the CD unit may be possible. (The Model CD-B measures 10.2 x 12.7 x 5.7 cm (4 x 5 x 2.25 in.) and weighs 0.7 kg (24.7 oz.)).
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1975
- Accession Number
- ADA021906
Entities
People
- Owen R. Green