DE2834478A1 - LEAK CURRENT DETECTOR DEVICE FOR OVERHEAD BUSES - Google Patents

Description

The present invention relates to a leakage current detector device with built-in safety device, for use in trolleybuses, the invention mainly perform the following two safety functions while the vehicle is moving:

a) Discharge of the electrostatic charges of the vehicle body to the negative pole of the contact line;

b) Continuous monitoring of the quality of the insulation between the vehicle body and the overhead contact line carrying the high voltage.

If there is a decrease in the insulation quality compared to a predetermined Resistance value occurs, the device comes into action by generating an optical-acoustic alarm and opening a switch in the traction circuit to stop the vehicle from moving. Using an appropriate sequence of Measures, the driver can restart the drive of the vehicle, taking safety precautions into account.

The detector device according to the invention is based on the fail-safe principle designed so that any faults in the detector system itself is detected and avoided in self-monitoring it becomes apparent that the system could provide output signals that would reduce safety.

The main features of the invention are in the attached Claims listed as well as in the following description, which refers to selected exemplary embodiments with reference to the accompanying drawings. In the drawing shows the only figure is a schematic block diagram of the functional principle of the detector circuit.

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The detector circuit is self-monitoring: when the vehicle's drive control circuit is put into operation, a monitoring period of about one minute is started, during which the malfunction alarm is given.

When the malfunction alarm is automatically terminated, the detector circuit is operational and in action. If the alarm does not end, this indicates that a fault current (leakage current) is present between the body and the catenary or that there is a fault in the detector circuit. One can now check whether it is a question of the presence of a fault current, by pressing an illuminated button. The latter brings the detector circuit back to its initial state, if it is is a temporary leakage current.

If the leakage current or the fault in the detector circuit persists, the vehicle can be started by inserting a key into a key switch and the key switch switches to the "off" position, whereby the acoustic alarm is switched off while the signal lamp indicating the alarm continues to burn.

The connection between the detector circuit and the vehicle body takes place at two different locations for security reasons.

The device comprises five functional assemblies, which are shown in the drawing:

a) an adapter for connection to the high-voltage contact line Via suitable voltage dividers and a rectifier stage, as well as interference protection means. The adapter enables the polarity to be changed at the high-voltage connections without any change

the operating conditions. In addition, the adapter has the function of removing the electrostatic charge

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fertilize the vehicle body to the negative pole what happens across a resistor with a total value of 47 kilo-ohms:

b) a signal generator that is operated by the voltage of the voltage divider and the between Vehicle body and ground line of the detector circuit feeds a suitable signal pulse, with signal generation and signal recognition by means of an automatic control of the characteristic Pulse voltage can be realized over the pulse duration;

c) a receiver, which acts as a discriminator for recognizing the corresponding to the regular operating conditions Signal is used and the alarm signals and a safety relay to operate a Switch in the driving circuit controls. The level value for the response of the detector circuit A fault current can be caused by switching on resistors in the range from 0.5 to Io iuA fault current be set;

d) a power supply part, the energy from the Refers to the vehicle battery and supplies the detector circuit in order to provide a galvanic separation between the battery and the high voltage circuit. The power supply part is for designed for an input voltage in the range of 18 to 32 V and against external overvoltages as well internal circuit errors secured. In any

In the event of a malfunction or if there is no supply voltage, the device works according to the fail-safe principle: i.e. the safety relay stops the vehicle movement and the alarm signals are put into action;

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e) a dashboard with control means, for example a test light button and a key to turn off the device.

The detector circuit indicated by a dashed line consists of three parts shown in the drawing:

1} a high voltage part that includes the adapter and directly is connected to the catenary of the vehicle. This part is highly insulated and in the high-voltage room of the vehicle housed;

2) a control circuit connected via a terminal M ₂ to the high-voltage part, to the battery, to the body and to the interference-free control;

3) a dashboard with an illuminated button to check for the presence of fault current (resetting the circuit) and for triggering the alarm light signal, with a key switch for deactivating the detector circuit and with an acoustic alarm device.

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Claims (4)

λαλι / * 7o Reg.-Mr. 125 7oS Z0J44 / 0 - Dr.-lng. Wolff t Ansaldo Societa Generale Elettromeccanica SpAHBartels Via N.!, Orenzi 8, Genua-Cornigliano (Italy) Dipl.-Chem. Dr. Brandes Dr.-lng. Held Dipl.-Phys. Wolff Leakage current detector device for trolleybuses. D - 7 Stuttgart 1, Lange Strasse Tel. (0711) 29 6310 and 29 72 95 : Telex 07 22312 (patwo d) Telegram address: tlx 07 22312 Wolff Stuttgart PA Dr. Brandes: Headquarters Munich Claims postal check. Stuttgart 7211-700 '■ ^c BLZ 60010070 Deutsche Bank AG, 14/286 30 BLZ 60070070 Office hours: 9-11.30 a.m., 1.30 p.m.-4 p.m. except saturdays August 2, 1978 482333 oda (1. \ Residual current detector device for overhead line omnibuses with a signal generator for introducing a suitable signal pulse between the vehicle body and the ground line of a detector circuit, a signal receiver that is able to distinguish the signal that is present under normal operating conditions and either generate alarm signals or otherwise actuate a safety relay to enable vehicle movement. 2. Apparatus according to claim 1, characterized in that the '' Signal generator with the high-voltage line via a suitable Adapter is connected, the resistor voltage divider, a rectifier stage and an interference protection device known type is formed. 3. Apparatus according to claim 2, characterized in that the adapter removes electrostatic charges from the vehicle body to the negative pole via suitable resistors, preferably via resistances of several tens Kilo-ohms. 4. Device according to claims 2 and 3, characterized by a signal generator and the receiver operating Power supply part, which is fed by a battery and contains known circuit means to a galvanic Separation between the battery and the high voltage circuits the device. Telephone information and Orders are only binding after a written 909808/0874 confirmation - ^ = - ORIGINAL INSPECTED