1533 — Three-Anode Mercury-Vapour and Gas-Filled Rectifying Valve
The 1533 is an industrial, directly heated, three-anode rectifying valve containing both mercury vapour and gas. It is designed specifically for high-power industrial rectification, such as battery charging systems, where it can deliver up to 15 A per valve and support a maximum of 110 lead-acid (Pb) cells. The tube features an oxide-coated filament, an auxiliary ignition electrode, and three separate anodes, housed in a heavy-duty construction designed for vertical mounting.
Mechanical Construction and Physical Dimensions
The 1533 is a physically robust valve with a net weight of 580 g and a shipping weight of approximately 3000 g. It must be operated strictly in a vertical, base-down position to ensure the correct distribution of the mercury-vapour fill.
The physical dimensions and terminal configurations are as follows:
- Maximum overall height: 270 mm
- Maximum bulb diameter: 74 mm
- Maximum width (including terminal projections): 192 mm
- Anode terminals: M6 threaded connectors located at the top of the anode structures.
- Auxiliary ignition terminal (ah): M4 threaded connector.
Filament and Heating Requirements
The valve utilizes a directly heated, oxide-coated filament designed for AC operation. Because it is a mercury-vapour and gas-filled tube, strict heating time delays (Tw) must be observed before anode voltage is applied to prevent damage to the cathode.
The calculated filament power of 43.7 W is derived from the nominal filament voltage of 1.9 V and filament current of 23 A (1.9 V x 23 A). For automated control of the preheating cycle, the use of the Philips type 4152 time delay switch is recommended.
Auxiliary Ignition and Typical Operating Characteristics
The 1533 features an auxiliary ignition electrode (ah) to facilitate reliable starting of the arc discharge. Under typical operating conditions, the tube exhibits the following characteristics:
- Arc Voltage Drop (Varc): 15 V
- Ignition Voltage (Vign): 45 V
To reliably achieve the 45 V ignition voltage, an auxiliary DC supply unit delivering approximately 100 V at 25 mA must be connected between the auxiliary ignition electrode ah (+) and the cathode (-). This connection must be made via a suitable current-limiting resistor. The Philips Auxiliary Ignition Unit type E3 108 03 is recommended for this purpose.
Electrical Ratings and Limiting Values
The operation of the 1533 is governed by strict limiting values (Grenzdaten) to ensure reliable operation and prevent backfiring or cathode destruction.
The transformer voltage limits (Vtr) are specified for a particular circuit configuration (referred to as Circuit c). The minimum series resistance (Rt) of 0.6 ohms is required to limit peak currents during operation. The operating temperature of the mercury (thg) must be maintained between 30 °C and 80 °C to ensure correct vapour pressure and prevent arc-back or failure to ignite.
Technical Summary
The 1533 is a specialized three-anode, mercury-vapour and gas-filled industrial rectifier. It features a high-current 1.9 V, 23 A directly heated filament, requiring a preheating time of 2 minutes under normal conditions, which must be extended to 5 minutes following transport or long service interruptions. With an auxiliary ignition electrode requiring a 45 V ignition supply, the tube provides efficient rectification with a low 15 V arc drop. It supports a maximum peak inverse voltage of 850 V, an average anode current of 5 A, and a peak anode current of 45 A, making it highly suitable for heavy-duty industrial battery charging and power rectification systems.
