Western electric 287 a brochure

Page 1

BELL SYSTEM PRACTICES SECTION AB46-287A
Transmission Engineering and Data Issue 3, 00t0ber 1962
Electron Tube Data A. T.& T. Co. Standard

ELECTRON TUBE DATA SHEET
WESTERN ELECTRIC 287A ELECTRON TUBE

70.212171 HIM"

"xi-IIIH\

DESCRI PTION

wry-vapor thyratron with a negative control
designed for regulated or controlled rectifiers.

................. 1250 2500 volts
hode Currant ............... 1.5 0.61. amperes

FILE: THYRATRON SECTION

© American Telephone and Telegraph Company 1962 287A

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2871 - Pig; 2
MQIHUA RATINGS, Absolute Values

Peak Anode Voltage
Inverse . . . . . . . . . . . . . . . ...... 1250 2500 volts
Forward..................... 1250 2500volts
Cathode Current

Peak....................... 6.0 2.5amperes
Average . . . . . . . . . . . . . . . . . 1.5 0.6L amperes
Surge (maximum duration 0.1 second) . . . . . . 0 25 amperes
Averaging Time. . . . . . . . . . . . . . . . . . 5 5 seconds

Negative Grid Voltage
Before Conduction . . . . . . . . . . . . . . . . 500 500 volts
During Conduction . . . . . . . . . . . . . . . . 10 10 volts
Positive Grid Current, Average
(averaging time - one cycle). . . . . . . . . . . .010 .010 ampere

Condensed Hercury Temperature Limits . . . . . . . . 4- 30 to +80 centigrade

ELECTRICAL DATA
Min. Bogey Max.
Filament Voltage . . . . . . . . . . . . . . . 2.37 2.5 2.62 volts

Filament Current at 2.5 volts. . . . . . . . . -- 7.0 7.75 amperes
Filament Heating Time Required . . . . . . . . 15 ~- -- seconds
Anode to Grid Capacitance. . . . . . a . . . . --'- 1.8 --- uuf.
Grid to Filament Capacitance . . . . . . . . . --- 5.0 --- uuf.

Deionizatinn Time, Approximate
Ebb-2500 volts;Ib-2.5 anperes;

EcchlS volts;THg-SOC;Rg-20000 ohms. . . . . --- 1000 --- microseconds

Ionization Time, Approximatez. . . . . . . . .

Ebb-100 volts;THg-L00;Grid Overvoltage-5 volts --- 150 --- microseconds

Ebb-100 volts:TEg-8OC;Grid Cvervoltage-25 volts --- 1 --- microsecond
Anode Voltage Drop . . . . . . . . . . . . . . --- 15 -- volts
Critical Grid Current at 220 Anode Volts . . . --- --- 5 microamperes

HE G DATA

Type of Cooling. . . . . . . . ..... Convection
Equilibrium Condensed Hercury Temperature
Rise Above Ambient, Approximate

At Full Load. . . . . . . . . . . . . . . . . . . 30 centigrade

At No Load. . . . . . . . . . . . . . . . . . . . 20 centigrade
Mounting Position. . . . . . . . . . . . . . . . . . Vertical- base down
Net Weight, Approximate. . . . . . . . . . . 3 ounces

Dimensions and pin connections shown in outline drawing on Page 1...

l.

Deionization time decrease& with an increase in negative grid voltage or
with a decrease in (a) condensed mercury temperature (THg), (b) grid resis-
tance or (c) anode current immediately preceding the end of conduction.
Ionization time decreases with an increase in (a) anode voltage, (b) con-
densed mercury temperature (THg) or (c) grid overvoltage. Grid overvoltage
is defined as the magnitude by which the applied voltage exceeds, in a
positive direction, the critical grid voltage value. Critical grid voltage
is the instantaneous value of grid voltage at the time when anode current
starts to flow.