MIL-PRF-24021K
c. Spikes from 0 to "600 volts from the average voltage level, with a 50-ohm source
impedance, a waveform as shown on figure 8, and a repetition range of 0 to 50 pulses per second.
Application of the spike shall not cause the monitor to disconnect power from the contactor.
d. The current drawn through the sense lead (pin B) shall be less than 50 milliamperes.
3.4.2.2 Inhibit voltage at pins C and E. The M24021-6 monitor shall be designed to accept at
pins C and E (see figure 7) an aircraft-generated direct DC potential of -15 to +80 volts (inhibit
voltage) originating at the starter system. When a 2 to 80 volt inhibit voltage is applied at pin C or
E and the monitor is in the reset state (the external contactor on figure 7 is energized), the monitor
shall remain reset and, in addition, shall be inhibited within 0.1 second from the time the
2 to 80 volt inhibit voltage is applied. In the inhibit mode of operation (2 to 80 volt inhibit voltage
is applied at pins C or E), the monitor shall accept any input voltage present at pin G (input at pin G
will be within the limits specified by curves on figure 9, 10 volts DC to 80 volts DC) and apply it to
the aircraft contactor at pin A. The maximum voltage drop between pins G and A shall be not
greater than 2.5 volts when the monitor input voltage is in the range of 10 to 29.1 volts DC. The 2
to 80 volt inhibit voltage shall not be applied to both pins C and E simultaneously when the monitor
is operating in the inhibit mode. When a 2 to 80 volt inhibit voltage is applied at pin C or E and the
monitor is in the trip state (monitor output at pin A is 0 volts), the monitor shall remain in the trip
state and shall reset only manually as specified in 3.4.4.2.1.
a. When an inhibit voltage of -15 to +1.5 volts is applied to both pins C and E, the monitor
shall function as specified in 3.4.4.2.1. If the inhibit voltage decreases from a higher value to a
voltage of less than 1.5 volts and the monitor is in the reset state (the external contact on figure 7 is
energized), the monitor shall function as specified in 3.4.4.2.1 within 0.1 second from the time the
inhibit voltage decreases to a voltage of less than 1.5 volts.
b. The non-inhibited (normal) requirements stated herein shall be met also when pin C or E or
both are not connected to any external circuit.
c. When the inhibit voltage at pins C or E is in the range of 1.5 to 2 volts, the monitor may
operate either in the inhibited or in the non-inhibited (normal) mode.
d. The internal circuit of the monitor shall incorporate a 10 kilo-ohm resistor in series with pin
C and a 10 kilo-ohm resistor in series with pin E.
3.4.3 Output requirements.
3.4.3.1 AC monitor including source of DC for contactor. When the external power applied to
the M24021-3 monitor meets the reset conditions specified in 3.4.4.1, the monitor shall, upon
momentary closing of the reset switch, activate a switching circuit which will apply a direct
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