TOSHIBA E3328 is a fixed frequency continuous wave magnetron intended for use in the industrial microwave heating applications. The average output power is 3kW in the frequency range from 2450 to 2470 MHz. The tube is a packaged magnet type. Water cooling for anode and forced air cooling for filter box are required. Forced air cooling for output dome is required in case of severe microwave load condition. Low pass filter for suppressing spurious leakage from the cathode stem is set in the filter box. The output is fed into a rectangular waveguide or into an oven directly. Coupling without the standard output coupler can be checked using E3328 impedance probe VM-06700. FEATURES (1) High efficiency (2) Compact size and light weight Total weight including magnets is 2.5 kg. (3) Quick start Operation can be started after 10 s preheating. (4) Low magnetic field leakage. (5) Minimum disturbance of atmosphere around device. Forced air cooling required is minimum. (6) Sufficient design margin for various types of application Isolator or circulator in the output circuit is not essential. The tube can be driven on single phase full wave doubler power source without filter. 2014 Toshiba Corporation 1
ELECTRICAL: Frequency (matched load) 2460±10 MHz Filament voltage 4.6 V Filament current 19 A Filament cold resistance 0.03 Ω Anode potential to be grounded Filament potential Negative high voltage MECHANICAL Physical dimensions See Dimensional Outline Terminal connection See Dimensional Outline Mounting position Cathode axis vertical Output coupling See attached drawing Magnetic field Ferrite magnet packaged Cooling : Anode Water Output antenna Forced air when necessary Filter box Forced air Weight (approx.) 2.5 kg Cathode type Directly heated thoriated tungsten filament ABSOLUTE MAXIMUM RATINGS (1) (2) (3) Min Max Unit Filament voltage (pre-heat) 4.4 4.8 V Filament surge current - 50 A Cathode pre-heating time 10 - sec Note 4 Filament voltage (operating) Vn-0.2 Vn+0.2 V ac Note 5 Anode surge voltage 10 - sec Note 4 Peak anode voltage - 5 kv Peak anode current - 1600 ma Average anode current - 1050 ma Average anode input power - 5 kw Load VSWR - 4 :1 Note 6 Anode temperature - 85 Note 7, 8 Temperature of ceramic seal - 220 Note 7 Case temperature - 80 Note 7 Cooling water outlet temperature - 65 Ambient atmosphere temperature - 50 when operating Storage temperature -30 60 Storage humidity - 95 % 2014 Toshiba Corporation 2
TYPICAL OPERATION (1) Unit RF Coupler Standard Anode power supply Three phase full wave rectified Frequency 2460 MHz Filament voltage (pre-heating) 4.6 V Filament voltage (operating) 2.2 V Peak anode voltage 4.7 kv Note 9 Average anode current 950 ma Average output power 3 kw Note 9 Load VSWR 1.05 :1 Cooling water flow : Anode 3 l/min Note 7 Cooling air flow : Filter box 60 l/min Note 7 Through filter box (Note 1) All the voltage parameters are in reference to the cathode voltage. (Note 2) None of the absolute maximum ratings should be exceeded under any circumstances even for an instant or a transient, since to do so may cause damage to the tube. (Note 3) Operation within the maximum ratings does not directly mean that tube life is guaranteed in that case. Case by case, some concrete limitations on operating conditions are required to guarantee the tube life. (Note 4) Minimum cathode preheating time required depends on the design of filament power supply. Generally, 10 seconds preheating time is enough to start magnetron operation. (Note 5) Filament voltage should be adjusted immediately after applying the anode voltage according to the reduction curve in Fig. 2. (Note (Note (Note (Note Vn is the nominal filament voltage of the reduction curve. 6) This maximum rating is allowed only for a short time transient. 7) Temperatures of seal portions of output ceramic dome and cathode stem ceramics should be lower than this maximum rating. 8) It is recommended to use the thermoswitch which opens the power supply circuit when the anode temperature exceeds 75 for protecting the tube. 9) These are measured within 15 seconds after applying anode voltage. The standard ambient temperature of the magnetron during these measurement is 25. Peak anode voltage goes down with operating time from this value to a lower value due to the reversible thermal reduction of the ferrite magnet field. 2014 Toshiba Corporation 3
Fig. 1 performance Chart Fig. 2 Filament voltage reduction Curve This is measured within 15 seconds after applying the anode voltage. Power supply : Three phase full wave rectified without filter Filament voltage : In accordance with Fig.1 load VSWR : 1.05 2014 Toshiba Corporation 4
Fig. 3 Rieke Diagram This is measured within 15 seconds after applying the anode voltage. Power supply : Three phase full wave rectified without filter Filament voltage : 2.2V Average anode current : 950mA Peak anode voltage : 4.7kV 2014 Toshiba Corporation 5
Fig. 4 Dimensional Outline Unit : mm 2014 Toshiba Corporation 6
Fig. 5 Standard Output Coupler Unit : mm Note (1) This drawing is to show the main dimensions of standard output coupler suitable for Toshiba E3328. (2) This is not an accessory part nor optional part. 2014 Toshiba Corporation 7
2014 Toshiba Corporation 8