Description
BW1608J2F is power triode of coaxial ceramic-metal construction. It is intended primarily for industrial RF heating machines. It comes with a removable water jacket. BW1608J2F has a water cooled Anode.
Electrical characteristics of BW1608J2F
Filament: Thoriated tungsten
Filament voltage (see note 1): 12 Volts
Filament Current: 178 Amps
Surge filament current (peak) (See note 2): 890 A max
Filament cold resistance: 8.0 mΩ
Peak usable cathode current: 70
Amp Amplification factor (Va = 10 kV, Ia = 5.0 A): 40
Mutual conductance (Va = 10 kV, Ia = 5.0 A): 80 mA/V
Inter-electrode capacitances:
Grid to anode: 47 pF
Grid to filament: 126 pF
Anode to filament: 2.0 pF
Mechanical characteristics of BW1608J2F
Overall dimensions: See outline Drawing
Net weight: 12 kg approx, 26.5 pounds approx
Mounting position: Vertical, either way up
Accessories
Water Coupling, supplied: PA709B
Thermal fuse: PA85G
Cathode Connector: PA830
Note: For frequencies above 2 MHz, PA830 should be used in conjunction with a strip connection to provide a low inductance cathode return.
Cooling
BW1608J2F has removable water jacket. Water cooling requirements are as follows:
| Anode plus grid Dissipation (kW) | Inlet temperature (°C) | Minimum rate of water flow (l/min) | Pressure drop (bar) | Outlet temperature (°C) |
|---|---|---|---|---|
| 50 | 20 | 30 | 0.27 | 45 |
| 50 | 50 | 73 | 1.38 | 60 |
| 30 | 20 | 20 | 0.10 | 43 |
| 30 | 50 | 45 | 0.72 | 60 |
| 15 | 20 | 10 | 0.07 | 45 |
| 15 | 50 | 24 | 0.15 | 60 |
The inlet water temperature must never exceed 50 °C. The pressure in the water jacket must not exceed 6 bars.
The temperature of the seals and envelope must not exceed 200 °C. Cooling of the seals by low velocity air flow is required.
Radio Frequency Oscillator For Industrial Service
(Class C conditions, one tube)
Maximum Ratings (Absolute Values)
Frequency: 30 MHz
Anode voltage: 13 kV max
Anode input power: 150 kW max
Anode dissipation: 50 kW
Grid voltage (negative value): 2.0 kV max
Grid Current
On load: 3.0 A max
Off load: 3.8 A max
Grid dissipation: 2.0 kW max
Grid Circuit resistance: 10 kΩ max
Cathode current: 16 A max
Typical Operating Conditions (Example 1)
Frequency: 30 MHz
Anode Voltage: 8.0 kV
Anode current: 8.0 A
Anode dissipation: 12.2 kW
Grid Voltage: -500 V
Grid resistor: 333 Ω
Grid current, on load: 1.5 A
Grid Current, off load: 2.4 A
Grid dissipation: 592 W
Feedback ratio (See note 4): 12.1 %
Drive Power: 1.4 kW
Output Power: 51.9 kW
Efficiency: 81.0 %
Oscillator output power (See note 5): 50.5 / 80.5 / 117.8 kW
Typical Operating Conditions (Example 2)
Frequency: 30 MHz
Anode Voltage: 10 kV
Anode current: 10 A
Anode dissipation: 17.3 kW
Grid Voltage: -630 V
Grid resistor: 315 Ω
Grid current, on load: 2.0 A
Grid Current, off load: 3.3 A
Grid dissipation: 947 W
Feedback ratio (See note 4): 11.8 %
Drive Power: 2.2 kW
Output Power: 82.7 kW
Efficiency: 82.7 %
Oscillator output power (See note 5): 80.5 kW
Typical Operating Conditions (Example 3)
Frequency: 30 MHz
Anode Voltage: 12 kV
Anode current: 12 A
Anode dissipation: 22.6 kW
Grid Voltage: -800 V
Grid resistor: 296 Ω
Grid current, on load: 2.7 A
Grid Current, off load: 3.5 A
Grid dissipation: 1500 W
Feedback ratio (See note 4): 12 %
Drive Power: 3.6 kW
Output Power: 121.4 kW
Efficiency: 84.3 %
Oscillator output power (See note 5): 117.8 kW
Notes:
Note 1: Temporary fluctuations up to +5% or –10% in filament voltage are permissible.
Note 2: The filament current of BW1608J2F must not exceed 890 A, even momentarily, at any time.
Note 3: If BW1608J2F is mounted with the anode uppermost, the water inlet and outlet connections should be reversed.
Note 4: The feedback ratio is defined as Vg (pk)/Va(pk) × 100 where Vg(pk) = peak r.f. grid voltage in volts and Va(pk) = peak r.f. anode voltage in volts.
Note 5: Oscillator output power = P out – P drive, where P out = output power of tube to anode circuit and P drive = drive power fed back to grid circuit.
