1553 — Three-Anode Industrial Rectifying Valve

The 1553 is a heavy-duty, three-anode, mercury-vapour and gas-filled rectifying valve designed for industrial power applications. It is primarily employed in industrial rectifier systems, capable of delivering up to 40 A per valve, and is rated for charging up to 110 lead-acid (Pb) cells. The tube features a directly heated, oxide-coated filament and requires vertical mounting with the base down.

Construction and Physical Characteristics

The 1553 is a physically large and robust industrial tube. It features a glass envelope with multiple external terminals to accommodate high currents and high-voltage isolation.

• Envelope and Terminals: The tube has three main anode connections (labeled $a$, $a'$, and $a''$) and an auxiliary ignition electrode (labeled $a_h$). The filament connections ($f, f$) are located at the base.
• Dimensions:
  • Maximum overall height: 327 ± 5 mm
  • Maximum bulb diameter: 124 mm
  • Maximum width across side terminals: 297 mm
  • Top cap diameter: Maximum 52 mm
• Weight:
  • Net weight: 1550 g
  • Shipping weight: 5150 g
• Mounting Position: The valve must be mounted strictly in a vertical position with the base down.

Filament and Heating Requirements

The 1553 utilizes a directly heated, oxide-coated filament designed for high-current operation. Due to the mercury-vapour filling, strict preheating times must be observed before anode voltage is applied to prevent damage to the cathode.

Preheating and Delay Considerations

The recommended preheating time ($T_w$) is 2 minutes. Under urgent operating conditions, this delay may be reduced to a minimum of 1 minute. To ensure the correct delay is maintained, the use of a time delay switch (such as the Philips type 4152) is recommended.

Following transport or after a long interruption of service, the preheating time must be extended to a minimum of 5 minutes ($T_w = 5\text{ minutes}$) to ensure that any condensed mercury is completely vaporized from the electrode structures before applying anode voltage.

Electrical Characteristics and Auxiliary Ignition

The 1553 operates with a low internal arc voltage drop, which is characteristic of mercury-vapour and gas-filled rectifiers, ensuring high efficiency.

• Arc Voltage ($V_{\text{arc}}$): Typically 15 V.
• Ignition Voltage ($V_{\text{ign}}$): Typically 50 V.

Auxiliary Ignition Circuit

To reliably achieve the required 50 V ignition voltage, an auxiliary D.C. supply unit must be connected to the tube. This auxiliary supply should deliver approximately 100 V with a current capability of 25 mA. It must be connected via a current-limiting resistor between the auxiliary ignition electrode ($a_h$, positive terminal) and the cathode (negative terminal). The Philips Auxiliary Ignition Unit type E3 108 03 is recommended for this purpose.

Limiting Values and Operating Conditions

The operation of the 1553 is governed by strict maximum and minimum limits to ensure reliable service and prevent premature failure.

The transformer voltage limits ($V_{tr}$) of 60 to 275 $V_{\text{eff}}$ apply under specific circuit configurations (referred to as Circuit c). The minimum surge limiting resistance ($R_t$) of 0.25 ̧ is required to protect the tube from excessive peak currents during start-up or transient conditions. The condensed mercury temperature ($t_{\text{Hg}}$) must be maintained within the range of 30 °C to 80 °C during operation to ensure proper vapor pressure and prevent arc-back or cathode sputtering.

Technical Summary

The 1553 is a three-anode, mercury-vapour and gas-filled industrial rectifying valve. It features a directly heated, oxide-coated filament operating at 1.9 V and a very high current of 70 A. Designed for heavy-duty industrial rectifiers, it can support up to 40 A per valve and charge up to 110 lead-acid cells. The tube requires a vertical, base-down mounting position, a preheating delay of 2 minutes (extendable to 5 minutes after transport), and an auxiliary ignition supply of 100 V / 25 mA connected to its ignition electrode. With a peak inverse voltage rating of 850 V and a peak anode current rating of 135 A, the 1553 is engineered for robust, high-efficiency industrial power rectification.