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1177

Directly heated Philips mercury-vapour or gas-filled industrial rectifier for very-high-current battery-charging installations up to about 110 lead-acid cells. Rated for approximately 850 V peak inverse voltage and 25 A output.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: SPECIAL
Socket code: -
Base pins: -
Nominal heater: 1.9 V / 45 A

Description

1177 — Single-Anode Mercury-Vapour and Gas-Filled Rectifying Valve

An industrial-grade, directly heated, single-anode rectifying valve filled with mercury vapour and gas, designed for high-current power rectification and battery charging applications.

Overview

The 1177 is a heavy-duty, single-anode rectifying valve containing a combination of mercury vapour and gas filling. It is designed specifically for industrial rectification systems, such as charging large lead-acid battery installations up to a maximum of 110 series-connected cells (Pb-accumulators), or providing high-current DC power for industrial machinery. The valve is rated to deliver a maximum of 25 A of average anode current, and its gas-mercury filling ensures a low internal voltage drop and high operating efficiency under heavy loads.

Mechanical Construction and Physical Dimensions

The physical design of the 1177 is optimized for high-current handling, thermal dissipation, and high-voltage isolation. The valve is housed in a large glass bulb with a body diameter of 125 mm. The maximum overall width, including the auxiliary ignition electrode terminal protruding from the side, is 145 mm, while the maximum diameter at the upper collar is 128 mm. The total height of the valve ranges from 342 mm to 362 mm.

Electrical connections are distributed across the envelope to prevent arc-over and ensure low contact resistance:

Anode (a): Located at the top of the envelope, terminated with an M8 threaded post to secure heavy-gauge anode cabling.
Auxiliary Ignition Electrode (ah): Positioned on the side of the bulb, terminated with an M4 threaded post.
Filament (f, f): Connected via heavy, flexible leads at the base of the valve to accommodate the high filament current.

The valve must be mounted in a vertical, base-down position to ensure the proper distribution of the liquid mercury and gas mixture during operation. The net weight of the device is 1060 g, and its shipping weight is 2720 g.

Filament and Heating Requirements

The 1177 utilizes a directly heated, oxide-coated filament. Due to the high emission requirements of the cathode, the filament operates at a very low voltage but requires a substantial current:

Filament Parameter	Value
Filament Voltage ( $V_f$ )	1.9 V
Filament Current ( $I_f$ )	60 A
Calculated Filament Power	114 W
Heating Supply	AC

Before anode voltage is applied, the filament must be preheated to establish the correct mercury-vapour pressure and prevent damage to the oxide coating. The recommended preheating time ( $T_w$ ) is 2 minutes. In urgent circumstances, this preheating period may be reduced to a minimum of 1 minute. To automate this startup sequence, a time delay switch (such as type 4152) can be integrated into the control circuitry. Following transport or a prolonged interruption of service, a longer preheating period of 5 minutes is mandatory to ensure all liquid mercury is vaporized from the electrodes.

Ignition and Auxiliary Circuitry

During normal conduction, the 1177 exhibits a low typical arc voltage drop ( $V_{\text{arc}}$ ) of 12 V. The required ignition voltage ( $V_{\text{ign}}$ ) to initiate the arc is documented between 22 V and 28 V.

To reliably achieve this ignition voltage, an auxiliary DC supply unit must be connected to the auxiliary ignition electrode "ah" (+) and the cathode (-). This auxiliary supply must deliver a minimum of 40 V and a current of at least 10 mA. A current-limiting resistor must be placed in series with the auxiliary electrode to protect the ignition circuit. An auxiliary ignition unit (such as type 1289) is recommended to satisfy these requirements.

Operating Characteristics

The 1177 can be configured in various rectifier circuits to deliver different output voltages and currents. The operating characteristics for several standard circuit configurations (designated a through g) are detailed below:

Circuit Configuration	Transformer Voltage ( $V_{\text{tr}}$ , $V_{\text{eff}}$ )	Output Voltage ( $V_o$ , V)	Output Current ( $I_o$ , A)
a	275	230	50
b	540	440	50
c	220	240	75
d	210	440	75
e	205	240	100
f	200	250	150
g	220	240	150

Absolute Maximum Ratings

The 1177 has two distinct sets of absolute maximum ratings (limiting values) depending on the operating temperature ranges and electrical stresses. Operating the valve beyond these limits can cause backfiring, cathode damage, or premature failure.

Parameter	Rating Set 1	Rating Set 2
Max. Peak Inverse Anode Voltage ( $V_{\text{ainv}_p}$ )	685 V	850 V
Max. Average Anode Current ( $I_a$ , $T_{\text{av}} = \text{max. } 5\text{ s}$ )	25 A	25 A
Max. Peak Anode Current ( $I_{ap}$ )	150 A	135 A
Max. Surge Anode Current ( $I_{\text{surge}}$ , $T = \text{max. } 0.1\text{ s}$ )	1500 A	1250 A
Min. Series Resistance ( $R_t$ )	0.1 $\Omega$	0.1 $\Omega$
Mercury Temperature Range ( $t_{\text{Hg}}$ )	30 to 80 °C	30 to 75 °C
Ambient Temperature Range ( $t_{\text{amb}}$ )	10 to 50 °C	10 to 45 °C

The series resistance ( $R_t$ ) represents the minimum protective resistance required in the anode circuit to limit surge currents during faults or transient conditions.

Technical Summary

The 1177 is an industrial-grade, single-anode, mercury-vapour and gas-filled rectifying valve. It features a directly heated, oxide-coated filament operating at 1.9 V / 60 A (requiring 114 W of heating power) and must be operated in a vertical, base-down position. The valve is characterized by a low arc voltage drop of 12 V and requires an auxiliary DC ignition supply of at least 40 V / 10 mA connected to its side-mounted auxiliary electrode to achieve reliable ignition. Depending on the thermal environment and circuit configuration, the 1177 can withstand peak inverse voltages up to 850 V and deliver average currents of 25 A per valve, making it a robust solution for high-power industrial rectification and battery charging systems.

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: SPECIAL
Socket code: -
Base pins: -
Nominal heater voltage: 1.9 V
Nominal heater current: 45 A
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

SPECIAL - Terminal pinout

Electrical assignments shared by every tube using this base designation.

No verified pinout is recorded for this base designation.

Section ratings

1 physical section, each with unique specifications.

Section 1

Rectifier

X-ray radiationInterelectrode capacitances

Rectifier peak inverse voltage: 850 V
Rectifier nominal output current: 25 A
Rectifier peak forward current: 135 A
Rectifier forward voltage drop: 12 V
Rectifier warm-up time: 120 s

Directly heated gas-filled rectifier with mercury-vapour/gas filling for industrial rectifier service up to 110 lead-acid cells.

Source-dependent data

Operating conditions by source

Each block preserves the test conditions and published values from one reference. Values from different sources are intentionally kept separate.

Data set 01

1963 Philips Electron Tubes Handbook V3

Published operating points and test conditions from this source.

SECTION 1

Rectifier

Characteristic

Arc voltage drop
12 V
GasFilled

Other

Maximum peak inverse anode voltage
850 V
Maximum average anode current
25 A
Maximum peak anode current
135 A
Maximum surge current
1250 A
ShortDuration
Application
industrial rectifier service up to 110 lead-acid cells
Heater voltage
1.9 V
DirectAC
Heater current
45 A
DirectAC

Data set 02

1999 Philips 0-D

Published operating points and test conditions from this source.

SECTION 1

Rectifier

Construction

Filling
Mercury vapour and gas

Characteristics

Arc voltage
12 V
Ignition voltage
28 V

Other

Peak inverse voltage
850 V

Circuit Configuration	Transformer Voltage ( $V_{\text{tr}}$ , $V_{\text{eff}}$ )	Output Voltage ( $V_o$ , V)	Output Current ( $I_o$ , A)
a	275	230	50
b	540	440	50
c	220	240	75
d	210	440	75
e	205	240	100
f	200	250	150
g	220	240	150

Circuit Configuration	Transformer Voltage ( $V_{\text{tr}}$ , $V_{\text{eff}}$ )	Output Voltage ( $V_o$ , V)	Output Current ( $I_o$ , A)
a	275	230	50
b	540	440	50
c	220	240	75
d	210	440	75
e	205	240	100
f	200	250	150
g	220	240	150

Circuit Configuration	Transformer Voltage ( $V_{\text{tr}}$ , $V_{\text{eff}}$ )	Output Voltage ( $V_o$ , V)	Output Current ( $I_o$ , A)
a	275	230	50
b	540	440	50
c	220	240	75
d	210	440	75
e	205	240	100
f	200	250	150
g	220	240	150