Description
3CX5000H3 is forced air-cooled, ceramic/metal power triode with a robust mesh filament, for use in industrial radio-frequency heating
Electrical Characteristics of 3CX5000H3
| Filament | thoriated tungsten |
| Filament voltage (see note 1) | 7.5 V |
| Filament current | 75 A |
| Surge Filament current (peak) (see note 2) | 375 A |
| Filament cold resistance | 11.8 mΩ |
| Peak usable cathode current | 20 A |
| Amplification factor | 20 |
| Grid to anode | 27 pF |
| Grid to filament | 54 pF |
| Anode to filament | 1.8 pF |
Mechanical Characteristics of 3CX5000H3
Connections: Filament leads and grid contact flanges
Operating position: vertical, either way up
Maximum operating temperature: 250 OC
Maximum dimensions: See outline drawing
Net weight: 4.7 kg (10 pounds) approx
Accessories
Cathode connector: CWPA830
Note: For frequencies above 2MHz, CWPA830 should be used in conjunction with a strip connection to provide a low inductance cathode return.
Cooling of 3CX5000H3
Sufficient air must be passed through the radiator to keep the temperatures of the ceramic to metal seals and of the anode (measured next to the radiator) below the maximum rated value of 250 degree C. The air flows required to maintain seal temperature at 225 degree C in an ambient temperature of 50 degree C and with an operating frequency of less than 30 MHz are shown in the following table.
An additional air flow is required for the filament seals. 8ft3/min directed at the centre contact ring, ½ inch below the outer contact ring, through a 1 ½ inch internal diameter air duct at 45 OC to the axis of the tube, is sufficient for operation up to 30 MHz at 50 OC ambient and 5000 ft altitude.
Minimum Radiator Air Flow Requirements of 3CX5000H3
| Anode Dissipation (Watts) | Sea Level | 5000 Feet | ||
|---|---|---|---|---|
| Air Flow (ft³/min) | Pressure Drop (inches Water) | Air Flow (ft³/min) | Pressure Drop (inches Water) | |
| 4000 | 98 | 0.24 | 118 | 0.29 |
| 5000 | 152 | 0.49 | 182 | 0.59 |
| 6000 | 236 | 1.00 | 283 | 1.20 |
The values given allow for maximum filament and grid dissipation in addition to the anode dissipation shown.
Radio Frequency Oscillator For Industrial Service
(Class C Conditions, One Tube)
Maximum Ratings of 3CX5000H3 (Absolute Values)
| Frequency | 90 MHz max |
| Anode voltage d.c. | 10 kV max |
| Anode current d.c. (see note 3) | 3.0 A max |
| Anode input power | 25 kW max |
| Anode dissipation | 5 kW max |
| Grid voltage d.c. | -1000 V max |
| Grid current d.c. (see note 4) | 0.5 A max |
| Grid dissipation | 200 W max |
| Cathode current d.c. | 4.0 A max |
Typical Operating Conditions of 3CX5000H3
| Frequency | 30 | 30 MHz |
| Anode voltage d.c. | 7.0 | 9.0 kV |
| Anode current d.c. | 2.65 | 2.52 A |
| Anode dissipation | 4.1 | 4.1 kW |
| Grid voltage d.c. | -700 | -900 V |
| Grid resistor | 3650 | 4900 Ω |
| Grid current d.c. | 192 | 184 mA |
| Grid dissipation | 44 | 42 W |
| Drive power | 179 | 208 W |
| Anode input power | 18.6 | 22.7 kW |
| Anode output power | 14.5 | 18.6 kW |
| Output power less drive | 14.3 | 18.4 |
