1049 — Double-Anode Mercury Vapour and Gas-Filled Rectifying Valve

The 1049 is a double-anode, mercury vapour and gas-filled rectifying valve designed primarily for industrial battery charging applications. It is capable of delivering up to 25 A per valve and is rated to charge up to a maximum of 20 lead-acid (Pb) cells.

Filament and Heating Requirements

The 1049 features a directly heated, oxide-coated filament. Due to the mercury-vapour and gas filling, strict adherence to filament heating times is required to prevent damage to the cathode during start-up.

Note: The calculated filament power is derived from the formula Pf = Vf * If using the nominal values of 1.9 V and 28.5 A.

The preheating time (Tw) is subject to specific operational conditions:

• Standard Operation: A recommended preheating time of 2 minutes is standard.
• Urgent Operation: If urgently required, the preheating time may be decreased to a minimum of 1 minute. To automate this delay, a type 4152 time delay switch can be integrated into the control circuitry.
• Post-Transport or Long Interruption: After transport or following a long interruption of service, the preheating time must be extended to Tw = 5 minutes to ensure proper distribution of the mercury vapour before anode voltage is applied.

Mechanical and Physical Specifications

The 1049 is a physically robust valve designed for vertical installation. It features top-cap anode connections and flexible filament leads at the base.

• Mounting Position: Vertical, base down.
• Maximum Overall Height: 280 mm.
• Maximum Bulb Diameter: 101 mm.
• Anode Connections: Two top-mounted terminals with M6 threading, spaced 25 mm apart.
• Filament Connections: Flexible leads at the base, with a spacing of 125 mm to 145 mm between mounting points.
• Net Weight: 520 g.
• Shipping Weight: 2400 g.

Electrical and Operating Characteristics

The electrical behavior of the 1049 is characterized by a low arc voltage drop and a low ignition voltage, typical of gas and mercury-vapour rectifiers.

• Arc Voltage (Varc): 9 V
• Ignition Voltage (Vign): 16 V

Operating Conditions in Charger Service

When operating in a typical charging circuit (designated as "Circuit a") with a transformer voltage (Vtr) of 60 Veff and a limiting resistance (Rt) of 0.5 Ohm, the valve exhibits the following characteristics across different states of battery charge:

Absolute Maximum Ratings

Operating limits are specified as absolute maxima and must not be exceeded under any service conditions.

• Peak Inverse Anode Voltage (Vainvp): max. 185 V
• Average Anode Current (Ia): max. 12.5 A per anode
• Peak Anode Current (Iap): max. 75 A
• Minimum Limiting Resistance (Rt): min. 0.3 Ohm
• Mercury Temperature Range (tHg): 30 to 80 °C

The minimum limiting resistance (Rt) of 0.3 Ohm must be maintained in the anode circuit to protect the valve from excessive current surges during operation. The operating temperature of the condensed mercury (tHg) must be kept strictly within the 30 to 80 °C range to ensure stable ionization and prevent backfiring or premature cathode degradation.