M 101 With Three-Place P.D.M. (Figure 158).

Arming. Same as original unit.

Delay-Action Bomb Firing. Same as original unit.

Normal Firing with Period-Delay Mechanism. A RED actucation closes K to contact No. 1, completing a circuit through thermistor Y, fuse V, and hold-on coil L. As Y heats, L holds K on its contact and V blows, energizing fuse-delay switch D. Upon completion of its delay period, D switches over, completing a circuit through thermistor K and fuse U. X, being cold, cannot pass enough current to operate L, and the circuit returns to nor-mal.

A second RED actuation causes repetition of the above, with X heating, U blowing, and fuse-delay switch E switching in the detonator and thermistor Z. Z, being cold, can-not pass enough current to operate L, and the cirucit again returns to normal.

A third RED actuation completes the circuit through Z, L and the detonator, which fires when the current rises to 1/4 ampere.

P.S.E. Firing. Same as original unit.

Figure 158 – M 101 Unit Circuit (with Three-Place P.D.M.)