Download 4CX1500B 8660

4CX1500B
RADIAL BEAM
POWER TETRODE
TECHNICAL DATA
J£DEC DESIGNATION
8660
The EIMAC 4CX1500B is a ceramic and
metal, forced air cooled, radial beam
tetrode with a rated maximum plate
dissipation of 1500 Watts.
It is a low
vol tage, high-current tube specifically
designed
for
exceptionally low
intermodulation distortion and low grid
interception.
The low distortion
characteristics make the 4CX1500B
especially sui table for radio-frequency
and audio-frequency linear amplifier
service.
GENERAL CHARACTERISTICS
l
ELECTRICAL
Cathode: OXlde Coated, Unipotential
Heating Time • • • .
Heater: Voltage • •
Current . . . . . . . . . . .
Transconductance:
(1=0.5 amperes, E 2=225 Volts) . • •
Min.
-3-
Nom.
Max.
6.0
9.0
11.0
Minutes
Volts
Amperes
30,000
Umhos
Direct Interelectrode Capacitance (Grounded Cathode)2
88
Cin . . . . . . . . . . . . . . .
75
12.8
Cout • • • • • • • • • . • • • . 10.8
0.3
Cgp • • • • • . • • •
pF
pF
pF
Direct Interelectrode Capacitance (Grounded Grid and Screen)2
Cin . . . . . . . . . . . . . . . . . . .
38
Cout • • • • • • . • • . . • • • . •
12
Cgp. • • • •
• • • . • •
0.005
pF
pF
pF
lCharacteristics and operating values are based upon performance
tests.
These figures may change without notice as the result of
addi tional data or product refinement.
Varian EH1AC should be
consulted before using this information for finil equipment design.
2capaci tance values
shielded fixture.
are
for
(Pub. 4940 Effective 9/15/86)
a
cold tube
as measured in a
special
2
4CX1500B
l>1ECHAN I CAL
Maximum Overall Dimensions:
Length
Diameter
Net Weight
• • . . • .
Operating Position
. . . .
. . . . . . . . . . .....
4.6 in
3.37 in
27 oz
Any
Maximum Operating Temperature:
Ceramic to Metal Seals
Anode Core
• • Special, Breechblock Terminal Surfaces
Base . • • • . • .
Recommended Socket . . . . . . . . . . . • • En-me SK-800 Series
RADIO FREQUENCY LINEAR AMPLIFIER
Class AB
MAXIMUM RATINGS:
DC Plate Voltage
DC Screen Voltage .
DC plate Current
Plate Dissipation • .
Screen Dissipation
Control Grid Dissipation
3000 Volts
400 Volts
0.900 Amperes
1500 Watts
12 Watts
1 Watt
4CX1500B
3
TYPICAL OPERATION
(Frequencies Below 30 MHz) Class AB2
Grid Driven, Peak Envelope or Modulation Crest Conditions
. · · · · · ·· ·
. . · · · ·
·
· · · · ·
· · · ·
·
· · ·
· ··
· · · · · ·
· · · · · · ·
· · · · · ·
· · · · ·
DC Plate Voltage
DC Screen Volta~e
DC Grid voltage
Zero-Signal DC Plate Current
Single-Tone DC Plate Current
Two-Tone DC Plate Current
Single-Tone DC Grid Current
Two-Tone DC Grid Current
Single-Tone DC Screen Current
Two-Tone DC Screen Current
Peak rf Grid ¥oltage
·
Driving Power
•.•
Useful Output Power .
·
Resonant Load Impedance
·
···
·· · ·
·
·
·
·
·
· ·
· ·
· ·
·- ··
2500
225
-34
300
720
530
1.3
0.06
-7
-11
46
1.5
900
1900
2750
225
-34
300
755
555
0.95
0.20
-14
-11
45
1.5
1100
1900
2'900
225
-34
300
710
542
0.53
0.06
-15
-11
41
1.5
1100
2200
Volts
Watts
Watts
Ohms
-38
-47
-40
-48
-43
-47
dB
dB
Volts
Volts
Volts
rnA
rnA
rnA
rnA
rnA
rnA
rnA
Intermodulation Distortion
Products 3
3rd Order
5th Order
.
· · · ·
· · ·
···
· · ·
lAdjust to the specified zero-signal plate current.
2The driving power specified includes
1000 ohm swamping resistor between
cathode.
the power dissipated in a
the control grid and the
3The intermodulation distortion products will be as specified or
better for all levels from zero-signal to maximum output power and
are referenced against one tone of a two equal tone signal.
4CX1500B
4
AUDIO AMPLIFIER OR MODULATOR
Class ABl
MAXIMUM RATINGS:
DC Plate Voltage
DC Screen Voltage .
DC Plate Current
Plate Dissipation .
Screen Dissipation
Grid Dissipation
. . .. .. . .. . . . . . . . .
· . . . . . . . . . . ... ..
3000 Volts
400 Volts
900 Amperes
1500 Watts
12 Watts
1. 0 ~vatt
TYPICAL OPERATION
(Sinusoidal wave, two tubes unless noted)
. · ·· ·· · · ·· ·· ·· ··
· ·· · · · · · ·
· ·· · ·
DC Plate Voltage
DC Screen Volta~e
. ·
· ·
DC Grid Voltage
Zero-Signal DC Plate Current
Max.-Signal DC Plate Current 2.
Zero-Signal DC Screen Current
Max.-Signal DC Screen Current 2
Effective Load, Plate to Plate
Driving Power
·
Max.-Signal Plate Output Power
. .
NOTE:
·
2900
Volts
2500
2000
325
325
Volts
325
Volts
-60
-60
-60
500
rnA
500
500
1.69
1.69 Amperes
1.68
-25
-20
rnA
-30
-32
rnA
-33
-27
1948
2715
3333 Ohms
· 16040 22580 27740 Watts
vJatts
· · · ·
· · · · ·
· · · · · · ·
· · ·
"TYPICAL OPERATION" data are obtained by calculation from
the published characteristic curves and confirmed by
direct tests.
Ac.j ustment of the grid bias to obtain the
specified zero-signal plate current is assumed.
When
grid drive is applied, the screen voltage required to
obtain the specified value of plate current without
drawing grid current may vary somewhat from the typical
values shown.
5
4CX1500B
APPLICATION
COOLING
The maximum temperature rating for the anode core of
the 4CXl500B is 250 o C.
Sufficient forced air circulation must
be provided to keep the temperature of the anode at the base of
the cooling fins and the temperature of the ceramic-to-metal seals
to below 250 o C.
Air flow requirements to maintain seal
o
temperature at 22S C in SOoC ambient air are tabulated below
(for operation below 30 megahertz).
Tube mounted in recommended
socket and chimney.
Sea Level
Plate
Dissipation
watts
1000
1500
Air Flow
CFM
18
34
10,000 feet
Pressure Drop
inches water
Air Flow
CFM
.23
.60
24
45
Pressure Drop
inches water
.31
.SO
·Since the power d~sipated by the heater represents about 60 watts and Since
grid plus screen dissipation can, under some conditions, represent another 13
watts, allowance has Oeen made in preparing this tabulation for an additional
73 watts dissipation.
The blower selected in a given application must be capable of
supplying the desired air flow at a back pressure equal to the
pressure drop shown above plus any drop encountered in ducts and
filters.
At other altitudes and ambient temperatures, the flow rate must be
modified to obtain equivalent cooling.
The flow rate and
corresponding pressure differential must be determined
individually in such cases, using rated maximum temperatures as
the criteria for satisfactory cooling.
HEATER
The rated heater voltage for the 4CXl500B is 6.0
Volts.
The voltage, as measured at the socket should be
maintained at this value to minimize variations in operation and
to obtain maximum tube life.
In no case should the voltage be
allowed to exceed 5% above or below the rated value.
The cathode and one side of the heater are internally connected.
It is recommended that the heater voltage be applied for a period
of not less than 3 minutes before other operating voltages are
applied.
From an initial cold condition, tube operation will
stabilize after a period of approximately 5 minutes.
6
4CX1500B
INTERMODULATION DISTORTION
The Radio Frequency Linear
Amplifier operating conditions including the distortion data are
the resul ts of actual operation in a neutralized grid-driven
amplifier.
Plots of H1 distortion versus power output under
two-tone conditions, as a function of zero-signal plate current,
are included to illustrate the effect of this parameter upon
distortion.
Because the 4CX1500B has very low grid interception,
it is possible to drive the grid positive without any adverse
effects upon the distortion level or upon the driver.
Class Ab
2
linear amplifier operation is therefore possible and recommended.
It is also recommended that a low impedance driver be used and
that the input of the 4CX1500B be swamped with a 1000 ohm resistor
from grid to cathode so as to provide an almost constant load to
the driver.
CONTROL-GRID OPERATION
The control gird dissipation rating of
the 4Cx1500B is 1 Watt.
The design features which make the
4CX1500B such an extremely linear tube also contribute to very low
grid interception.
It will be found that the grid will be driven
into the positive grid region in the typical operation of the
tube.
The grid current will usually be less than 1.0 milliampere.
SCREEN-GRID OPERATION
'retrode tubes may exhibi t reversed
screen current to a greater or lesser degree depending on
individual tube design.
This characteristic is prominent in the
4CX1500B and, under some operating conditions, indicated negative
screen currents in the order of 35 milliamperes may be
encountered.
The maximum rated power dissipation for the screen grid in the
4CX1500B is 12 Watts and the screen power should be kept below
this level.
The product of the peak screen voltage and the
indicated dc screen current approximates the screen input power
except when the screen current indication is near zero or
negative.
In the usual tetrode amplifier, where no signal voltage
appears between cathode and screen, the peak screen voltage is
equal to the dc screen voltage.
Experience has shown that the
screen will operate within the limits established for this tube if
the indicated screen current,
plate voltage and drive voltage
approximate the "Typical Operation" values.
The screen supply voltage must be maintained constant for any
values of negative and positive screen currents that may be
encountered.
Dangerously high plate currents may flow if the
screen power supply exhibits a rising voltage characteristic with
nega ti ve screen current.
Stabilization may be accomplished in
several different wayS.
A bleeder resistor may be connected form
screen to cathode; a combination of VR tubes may be connected from
screen to cathode; or an electron-tube regulator circuit may be
used in the screen supply.
It is absolutely essential to use a
bleeder if a series electron-tube regulator is employed.
The
screen bleeder current should approximate 70 milliamperes to
adequately stabilize the screen voltage.
It should be observed
that this bleeder power may be usefully employed to energize
low-power stages of the transmitter.
4CX1500B
7
PLATE OPERATION
The maximum rated plate dissipation power is
1500 Watts.
Except for brief periods during circuit adjustments,
this maximum value should not be exceeded.
The top cap on the anode cooler may be used as a plate terminal at
low frequencies or a circular clamp or spring-finger collet
encircling the cylindrical outer surface of the anode cooler may
be used at high frequencies.
Points of electrical contact with the anode cooler should be kept
clean and free of oxide to minimize radio-frequency losses.
The
anode cooler shoulc~ be inspected periodically and cleaned when
necessary to remove any dirt which might interfere with effective
cooling.
SPECIAL APPLICATIONS
If it is desired to operate this tube
under conditions different frofl1 those given here, write to the
Power Gr iG Tube r,~ark.eting Department, Varian EIJ:.1AC, 1678 South
Pioneer Road, Salt Lak.e City, UT 84104, for information and
recommendations.
CAUTION-HIGH VOLTAGE
Operating voltage for this tube can be
o.eClcHy, so the equipment must be designed properly and operating
precautions must be followed.
Design equipment so that no one can
come in contact with high voltages.
All equipment must include
safety enclosures for high voltage circuits and terminals, with
inter lock swi tche s to open the priILIary circuits of the power
supply and to discharge high voltage capacitors whenever access
doors are opened.
Interlock switches must not be bypassed or
"cheated" to allow operation with access doors open.
Always
remember that HIGH VOLTAGE CAN KILL.
I
1
EIMAC 4CXI500B
EIMAC 4CX 1500B
TYPICAL 1M PRODUCTS VS. POWER OUTPUT
TYPICAL 1M PRODUCTS VS. POWER OUTPUT
(AS A FUNCTION OF ZERO SIGNAL PLATE CUlRENT)
(AS A FUNCTION OF ZERO SIGNAL PLATE CURRENT!
.,
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EIMAC 4CXI500B
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.,~
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EIMAC 4CX I500B
TYPICAL 1M PRO[)JCTS VS. POIIER OUTPUT
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