M762: Std, MSR12886002, Dec 88.
M762A1: Feb 01.
Electronic Time (ET) Fuze M762 Series is used with l05mm cartridges and 155mm and 8-inch projectiles carrying payloads that are expelled during projectile flight (airburst). The M762A1 fuze is not authorized for use with 8-inch projectiles.
The fuze contains an electronic timing system that may be set to function from 0.5 to 199.9 seconds in increments of tenths of a second. When used with weapons equipped with auto-setters, the fuze will be automatically remote set prior to launch via an inductive communication link between the fuzed ammunition and the weapon fire control system. The fuze can also be set via inductive communication link with a portable hand-held fuze setter. In addition, the fuze can be hand set (without the need of any tool) by rotating the OGIVE while depressing a thumb operated selector and cocking button until the desired time appears in the liquid crystal display (LCD) window. The ogive of the M762A1 can be rotated bi-directionally to provide quicker manual setting. The fuze is powered by a reserve lithium battery.
In the time mode, overhead safety is provided by an S&A that arms at 50 milliseconds prior to set time. When set for PD, the fuze is armed at 0.5 seconds in flight.
The fuze is energized as follows: rotation of the ogive or an inductive command from an auto-setter initiates the Battery Primer which breaks a glass ampule within the battery, releasing electrolyte fluid to power-up the battery and energize the fuze.
Upon weapon firing, setback and centrifugal forces act on the electromechanical S&A: the setback force moves the setback lock clear of the slider; at the muzzle exit, spin force frees the spin lock from the slider and disrupts the electrical shortening across the piston actuator (PA); when set for time, an electrical pulse activates the PA at 50 milliseconds prior to set time; when set for PD, the pulse activates the PA at 0.45 seconds in flight; the PA moves the slider, locking it into the armed position thereby disrupting the electrical short across the Electric Detonator; and connecting the Electric Detonator terminal to the firing circuit.
When a time setting expires, the electronics assembly sends a fire pulse through the firing circuit and detonates the Electric Detonator. For PD function, the crush switch assembly senses the impact and transmits a fire signal to detonate the Electric Detonator. The output of the Electric Detonator functions the lead charge which initiates projectile functioning.
Difference Between Models:
The M762A1 functions the same as the M762 but contains improved capabilities. The fuze ogive can be rotated bi-directionally to provide quicker manual setting. The LCD readout for PD is simplified to diminish the probability for manual setting errors. A battery bleed-down circuitry is added to facilitate render safe procedures. The fuze electronics is improved to provide more robustness in the operational environment and faster power on rise time for quicker response to autoset commands. The fuze can be passively interrogated by an autosetter to ascertain battery status and previously loaded setting data.
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