Eimac, 3-500Z

HIGH MU POWER TRIODE

The Elmac 3-500Z is a compact power triode intended to be used as a zero-bias Class AB₂ amplifier in audio or radio-frequency applications. Operation with zero grid bias simplifies associated circuitry by eliminating the bias supply. In addition, grounded-grid operation is attractive since power gain as high as twenty times can be obtained with the 3-500Z in a cathode-driven circuit.

From brochure by Eimac, Effective 9/15/91.
Varian
power grid & x-ray tube products
1678 South Pioneer Road / Salt Lake City, Utah 84104 / U.S.A. / (801) 972-5000

GENERAL CHARACTERISTICS

Characteristics and operating values are based upon performance tests. These figures may change without notice as the result of additional data or product refinement. Varian Power Grid & X-Ray Tube Products should be consulted before using this information for final equipment design.

ELECTRICAL

Filament: Thoriated Tungsten

Voltage	5.0 +/- 0.25 Volts
Current @ 5.0 Volts	14.6 Amperes
Amplification Factor(Average)	130

Direct lnterelectrode Capacitance (Grounded Filament)²

Cin	8.3 pF
Cout	0.07pF
Cgp	4.7 pF

Direct lnterelectrode Capacitance (Grounded Circuit)²

Cin	8.3 pF
Cout	4.7 pF
Cgp	0.07pF
Frequency of Maximum Rating(CW)	110 MHz

² Capacitance values are for a cold tube as measured in a special shielded fixture

Maximum Overall Dimensions:

Length	6.10 in; 154.94 mm
Diameter	3.44 in; 87.33 mm
NetWeight	7oz; 198.5 gm
Operating Position	Vertical, base up or down

Maximum Operating Temperature:

Plate Seals	225 ° C
Base Seals	200 ° C
Cooling	Radiation and ForcedAir
Base	5 Pin Special
Recommended Socket	Varian SK-410
Recommended Chimney	VarianSK-406

Recommended Heat-Dissipating Connector:

Plate

HR-6

RADIO FREQUENCY LINEAR AMPLIFIER

CATHODE DRIVEN

(Frequencies to 110 MHz)
Class AB₂

MAXIMUM RATINGS:

DC PLATE VOLTAGE	4 000 VOLTS
DC PLATECURRENT	0.4 AMPERE
PLATE DISSIPATION	500 WATTS
GRID DISSIPATION	20 WATTS

Zener diode positive bias used at plate potentials of 3 kV and above
Approximate value
Currents listed correspond to SSB, or "Two-tone" average current at peak of signal envelope
Single-tone current for 3500 Vdc operation may reach this value during short periods of circuit adjustment only
Intermodulation distortion products are referenced against one tone of a two tone signal

TYPICAL OPERATION
Class AB₂, Peak Envelope or Modulation Crest Conditions

PlateVoltage	1500	2000	2500	3000	3500	Vdc
Cathode Voltage¹	0	0	0	+10	+15	Vdc
Zero Signal Plate Current²	65	95	130	62	53	mAdc
Single-Tone Plate Current, CW³ ⁴	400	400	400	400	400	mAdc
Two-Tone PIate Current	260	270	280	268	262	mAdc
Single-Tone Grid Current²	130	130	120	108	108	mAdc
Two-Tone Grid Current²	80	80	70	60	58	mAdc
Single-Tone Power Input	600	800	1000	1200	1400	W
Useful Output Power CW or PEP	330	500	600	740	890	W
Resonant Load Impedance	1600	2750	3450	4200	5000
Intermodulation Distortion Products⁵
3rd Order	-46	-38	-33	-40	-40	db
5th Order	-	-	-	-46	-45	db
Driving Impedance	94	102	100	115	115
Maximum Signal Driving Power²	49	49	46	46	46	W

RADIO FREQUENCY POWER AMPLIFIER OR OSCILLATOR

GRID DRIVEN, CATHODE DRIVEN

Class AB₂ and C Telegraphy or FM
(Key-Down Conditions)

(Frequencies to 110 MHz)

MAXIMUM RATINGS:

DC PLATE VOLTAGE	4 000 VOLTS
DC PLATECURRENT	0.35 AMPERE
PLATE DISSIPATION	500 WATTS
GRID DISSIPATION	20 WATTS

TYPICAL OPERATION

	Grid Driven		Cathode Driven
PIateVoltage	3000	3500	3000	3500	Vdc
Grid Voltage	-10	-75	-10	-75	Vdc
Plate Current	350	300	333	350	mAdc
Grid Current	115	115	108	118	mAdc
Peak rf (Cathode) (Grid)Voltage	110	187	95	200	V
Approximate Driving Power	14	22	35	81	W
Plate Input Power	1050	1050	1000	1225	W
Plate Dissipation	330	200	300	305	W
Useful Output Power	720	850	700	920	W
Resonant Load Impedance	4200	5700	4800	5500	ohms

PLATE MODULATED RADIO FREQUENCY POWER AMPLIFIER

GRID DRIVEN

Class C Telephony (Carrier Conditions)

MAXIMUM RATINGS:

DC PLATE VOLTAGE	3 000 VOLTS
DC PLATECURRENT	0.275 AMPERE
PLATE DISSIPATION¹	330 WATTS
GRID DISSIPATION²	20 WATTS

Corresponds to 500 watts at 1 000/0 sine-wave modulation
Average, with or without modulation

TYPICAL OPERATION
(Frequencies to 30 MHz)

Plate Voltage	3 000 Vdc
Grid Voltage	-100 Vdc
Plate Current	275 mAdc
Grid Current¹	120 mAdc
Peak rf Grid Voltage¹	200 v
Calculated Driving Power	25 W
Plate Input Power	825 W
Plate Dissipation	185 W
Plate Output Power	640 W

Approximate value

AUDIO FREQUENCY POWER AMPLIFIER OR MODULATOR

Class AB₂, Grid Driven (Sinusoidal Wave)

MAXIMUM RATINGS (Per Tube):

DC PLATE VOLTAGE¹	4000 VOLTS
DC PLATE CURRENT	0.4 AMPERE
PLATE DISSIPATION	500 WATTS
GRID DISSIPATION	20 WATTS

TYPICAL OPERATION (Two Tubes)

PlateVoltage	3000 Vdc
Grid Voltage	0 Vdc
Zero-Signal Plate Current²	300 mAdc
Maximum Signal Plate Current	770 mAdc
Max Signal Grid Current²	244 mAdc
Peak af Grid Voltage³	100 V
Peak Driving Power⁴	25 W
Plate Input Power	2310 W
Maximum Signal Plate Dissipation	890 W
Plate Output Power	1420 W
Load Resistance(plate to plate)	8600 ohms

See zero-bias operation in Application Section
Approximate value
Per tube
Nominal drive power is one-half peak power

HIGH-LEVEL MODULATED RADIO FREQUENCY AMPLIFIER

PULSE-WIDTH MODULATION - GRID DRIVEN

ABSOLUTE MAXIMUM RATINGS:

	RF Amplifier	Switching Modulator
DC Plate Voltage	4	10	KILOVOLTS
DC Plate Current	0.4	0.4	AMPERES
DC Grid Voltage	-200	-200	VOLTS
Plate Dissipation	500	500	WATTS
Grid Dissipation	20	20	WATTS
TYPICAL OPERATION (Carrier Conditions)	RF Amplifier	Switching Modulator
Plate Voltage	3.0	9.0	kVdc
Plate Current	250	180	mAdc
Grid Voltage	-85	-120	Vdc
Grid Current²	170	125	mAdc
Useful PowerOutput²	550	1500	W

These conditions assume rectangular drive waveform and a third harmonic, high-efficiency "Tyler" circuit
Approximate value

NOTE:

TYPICAL OPERATION data are obtained by calculation from published characteristic curves or actual measurement. Adjustment of the rf grid voltage to obtain the specified plate current at the specified bias and plate voltages is assumed. If this procedure is followed, there will be little variation in output power when the tube is changed, even though there may be some variation in grid current. The grid current which results when the desired plate current is obtained is incidental and varies from tube to tube. These current variations cause no difficulty so long as the circuit maintains the correct voltage in the presence of the variations in current. If grid bias is obtained principally by means of a grid resistor, the resistor must be adjustable to obtain the required bias voltage when the correct rf grid voltage is applied.

RANGE VALUES FOR EQUIPMENT DESIGN

	Min	Max
Filament: Current at 5.0 Volts	13.8	15.0	Amperes
Interelectrode Capacitance¹ (Grounded Filament Connection)
Input	6.5	10.0	pF
Output	-	0.18	pF
Feedback	4.2	5.2	pF
Interelectrode Capacitance¹ (Grounded Grid Connection)
Input	6.5	10.5	pF
Output	4.2	5.2	pF
Feedback	-	0.18	pF
Zero Signal Plate Current:
(Ec=0Vdc Eb=Vdc)	90	180	mAdc

¹In shielded fixture

APPLICATION

MECHANICAL

MOUNTING - The 3-500Z must be operated vertically, base up or down. A flexible connecting strap should be provided between the heat dissipating plate connector and the external plate circuit. The tube must be protected from severe vibration and shock.

SOCKET - The EIMAC SK-410 air system socket and the SK-406 chimney are recommended for use with the 3-500Z. When a socket other than the SK-410 is used, provisions must be made for equivalent cooling of the base, the envelope, and the plate lead.

If a socket other than the EIMAC SK-410 Is employed, the user should assure himself that strong lateral pressure is not applied to the tube base pins. Otherwise, even though the base of the tube is reinforced, damage to the base seals may result.

CAUTION-GLASS IMPLOSION - The EIMAC 3-500Z is pumped to a very high vacuum, which is contained by a glass envelope. When handling a glass tube, remember that glass is a relatively fragile material, and accidental breakage can result at any time. Breakage will result in in flying glass fragements, so safety glasses, heavy clothing, and leather gloves are recommended for protection.

COOLING - Forced-air cooling is required to maintain the base seals at a temperature below 200 ° C. Air flow requirements to maintain the above maximum temperatures are tabulated below (For operation below 30 MHz).

Base-to-Anode Air Flow
Anode Dissipation (Watts)	Air Flow (CFM)	Preassure Drop (inches-H₂O)
300	6.6	0.023
400	10.3	0.052
500	13.0	0.082

The anode of the 3-5002 operates at a visibly red color at its maximum rated dissipation of 500 Watts.

In all cases, air flow rates in excess of the minimum requirements will prolong tube life. NOTE: Two 3-500Z tubes in a single amplifier, chassis mounted, may be adequately cooled by use of a fan so mounted as to pressurize the space below the sockets. Fans suitable for use at or near sea level are Pamotor Model 2000, or Model 6500. The Rotron "Spartan" fan (3200 rpm) is also suitable, as is a #3, 3 inch squirrel cage blower (31 00 rpm) all cases, the only criteria of proper cooling is the temperature of the tube seals Tube temperatures may be measured with the aid of temperature sensitive paint, spray or crayon.

Suitable products are manufactured by the Tempil Division, Big Three lndustrial Gas & Equipment Co., Hamilton Blvd., So Plainfield, New Jersey 07080.

ELECTRICAL

FILAMENT OPERATION - The rated filament voltage for the 3-500Z is 5.0 volts. Filament voltage, as measured at the socket, should be maintained within the range of 4.75 to 5.25 volts to obtain maximum tube life.

For best tube life, the inrush current to the filament should be limited to two times normal current during turn-on. This will minimize thermal stress on the thoriated-tungsten filament wire, which can cause internal tube geometry changes with repeated cycling.

HIGH VOLTAGE - Operating voltage for this tube can be deadly, 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 interlock switches to open the primary 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.

INTERMODULATION DISTORTION - Typical operating conditions with distortion values included are the result of data taken during actual operation at 2 MHz. Intermodulation values listed are those measured at the full peak envelope power noted

INPUT CIRCUIT - When the 3-500Z is operated as a grounded-grid rf amplifier the use of a resonant tank in the cathode circuit is recommended in order to obtain greatest linearity and power output. For best results with a single-ended amplifier it is suggested that the cathode tank circuit operate at a Q of two or more.

SPECIAL APPLICATIONS - If it is desired to operate this tube under conditions different from those given here, write to the Power Grid Tube Marketing Department, Varian, 1678 South Pioneer Road, Salt Lake City, Utah 84104, telephone (801) 972-5000, for information and recommendations.

Tube dimentions

Socket dimentions

DIMENSIONAL DATA
	INCHES			MM
DIM.	MIN.	MAX.	REF.	MIN.	MAX.	REF.
A		3.438			87.33
B	.350	.365		8.89	9.27
C	.328	.359		8.33	9.12
D		5.200			132.1
E	5.500	6.100		139.7	154.94
F	.700			17.78
G
H
I
J		2.500			63.5
K			30 °
L	.185	.191		4.7	4.85
M			1.250			31.75

NOTES

REF DIMENSIONS ARE FOR INFO ONLY & ARE NOT REQUIRED FOR INSPECTION PURPOSES
METRIC EQUIVILENTS TO TME NEAREST 0.01mm, ARE GIVEN FOR GENERAL INFO ONLY & ARE BASED ON 1 INCH = 25.4 mm.
ONLY BASE PINS "L" ARE SO ALIGNED THAT THEY CAN BE FREELY INSERTED INTO A GAGE 1/4" THK. WITH HOLE DIAS. OF .204 LOCATED ON TRUE CENTERS BY THE GIVEN DIMS. "K" & "M".

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Click HERE to study the example design by Eimac on a pair of 3-500Z tubes.

Eimac is available at http://www.eimac.com/.

3-500Z is now produced by Triton Services, Inc of Dunkirk, MD USA. They may be contacted at Triton Electron Technology Division, 3100 Charlotte Avenue, Easton, PA 18042. Phone - 610 252-7331, FAX - 610 258-6279.):

This page has ben scanned and OCR'ed from the Eimac data-sheet. Sincere effort has been given to provide an accurate and correct replication. However, no guaranty is provided for the consequences of any errors on this page, or anyone linked from here. Further, no responsibilities, legal, financial or others will be accepted based on or connected to this page. It has only been provided to the aide of the Radio Amateur Community.