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1. WO2001078208 - PROCEDE DE PROTECTION D'UN GENERATEUR DE COURANT CONTINU (CC) CONTRE DES SURTENSIONS

Note: Texte fondé sur des processus automatiques de reconnaissance optique de caractères. Seule la version PDF a une valeur juridique

[ EN ]

CLAIMS

1. A method for protecting a DC generator against overvoltage m the event of a loss of load,
c h a r a c t e r i s e d m that
a voltage limit value is defined,
when starting the current generator, one or a few small current pulses are generated during an initial phase,
the voltage is measured across the output of the current generator during the initial phase,
the voltages measured across the output of the current generator are compared with the voltage limit value, and
normal operation is started only if all the voltages across the output of the current generator measured during the initial phase are below the voltage limit value and the current generating is interrupted and a loss of load is indicated if any one of the voltages across the output of the current generator measured during the initial phase exceeds the voltage limit value .
2. A method according to claim 1, used m starting the supply of direct current to an electrostatic precipitator, comprising discharge electrodes and collecting electrodes, with the object of maintaining a constant or varying DC voltage between these electrodes.
3. A method according to claim 1, used in starting the supply of pulsating direct current to an electrostatic precipitator, comprising discharge electrodes and collecting electrodes, with the object of maintaining a constant or varying DC voltage between these electrodes.

4. A method according to claim 1, used m starting the supply of direct current from a frequency-modulated voltage transducer, the output voltage of which is transformed and rectified, to an electrostatic precipitator, comprising discharge electrodes and collecting electrodes, with the object of maintaining a constant or varying DC voltage between these electrodes.
5. A method according to any one of the preceding claims,
c h a r a c t e r i s e d in that
the voltage limit value is considerably less than both the maximal permitted output voltage of the DC generator and the normal operating voltage for the applica-tion, and preferably is between 10% and 50% of the normal operating voltage.
6. A method according to any one of the preceding claims ,
c h a r a c t e r i s e d in that
the total charge that is applied during the initial phase is selected in such a way that the current generator without load obtains an output voltage between the voltage limit value and the normal operating voltage.
7. A method according to any one of the preceding claims,
c h a r a c t e r i s e d in that
the total charge that is applied during the initial phase is selected in such a way that the current generator with load obtains an output voltage below the voltage limit value, preferably considerably below the voltage limit value.
8. A method according to any one of the preceding claims ,
c h a r a c t e r i s e d in that
the total charge that is applied during the initial phase is selected in such a way that the current generator with load obtains an output voltage below 10% of the normal operating voltage, preferably below 1% of the normal operating voltage.
9. A method according to any one of the preceding claims ,
c h a r a c t e r i s e d in that the duration of the initial phase is less than 1 second, preferably less than 0.1 second and particularly less than 0.01 second.
10. A method according to any one of the preceding claims ,
c h a r a c t e r i s e d in that
the initial phase comprises 1-10 pulses, preferably 1-2 pulses, each with a duration less than 10 microseconds, preferably less than 5 microseconds.

AMENDED CLAIMS
[received by the International Bureau on 14 September 2001 (14.09.01);
original claims 1-10 replaced by new amended claims 1-9 (3 pages)]

1. A method for protecting a DC generator against overvoltage in the event of a loss of load, the method being used in starting the supply of direct current to an electrostatic precipitator, comprising discharge
electrodes and collecting electrodes, with the object of maintaining a constant or varying DC voltage between these electrodes.
c h a r a c t e r i s e d in that
a voltage limit value is defined,
when starting the current generator, one or a few small current pulses are generated during an initial phase,
the voltage is measured across the output of the current generator during the initial phase,
the voltages measured across the output of the current generator are compared with the voltage limit value, and
normal operation is started only if all the voltages across the output of the current generator measured during the initial phase are below the voltage limit value and the current generating is interrupted and a loss of load is indicated if any one of the voltages across the output of the current generator measured during the initial phase exceeds the voltage limit value .
2. A method according to claim 1, used in starting the supply of pulsating direct current to an electrostatic precipitator, comprising discharge electrodes and collecting electrodes, with the object of maintaining a constant or varying DC voltage between these electrodes.

3. A method according to claim 1, used in starting the supply of direct current from a frequency-modulated voltage transducer, the output voltage of which is transformed and rectified, to an electrostatic precipitator, comprising discharge electrodes and collecting electrodes, with the object of maintaining a constant or varying DC voltage between these electrodes.
4. A method according to any one of the preceding claims,
c h a r a c t e r i s e d in that
the voltage limit value is considerably less than both the maximal permitted output voltage of the DC generator and the normal operating voltage for the applica-tion, and preferably is between 10% and 50% of the normal operating voltage.
5. A method according to any one of the preceding claims ,
c h a r a c t e r i s e d m that
the total charge that is applied during the initial phase is selected m such a way that the current generator without load obtains an output voltage between the voltage limit value and the normal operating voltage.
6. A method according to any one of the preceding claims,
c h a r a c t e r i s e d in that
the total charge that is applied during the initial phase is selected in such a way that the current generator with load obtains an output voltage below the voltage limit value, preferably considerably below the voltage limit value.
7. A method according to any one of the preceding claims ,
c h a r a c t e r i s e d in that
the total charge that is applied during the initial phase is selected in such a way that the current generator with load obtains an output voltage below 10% of the normal operating voltage, preferably below 1% of the normal operating voltage.
8. A method according to any one of the preceding claims ,
c h a r a c t e r i s e d m that the duration of the initial phase is less than 1 second, preferably less than 0.1 second and particularly less than 0.01 second.
9. A method according to any one of the preceding claims,
c h a r a c t e r i s e d m that
the initial phase comprises 1-10 pulses, preferably 1-2 pulses, each with a duration less than 10 microseconds, preferably less than 5 microseconds.