EP0066950A1
Expired / Lapsed
EP
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Method of protecting a thyristor switch of a pulse generator
Assignee: FLSmidth and Co AS
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Filing: 1982-04-28
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Granted: —
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Expires: 2002-04-28
Abstract
Abstract Method of protecting a thyristor switch element, of a pulse generator supplying a capacitive load, against damage during sparkovers which occur in the load, the method comprising triggering the thyristor or thyristors (T) in the switch element to conduction if a sparkover occurs in the load (CF) during a period of pulse decay. This can be achieved by starting a timer whenever a pulse starts, the timer running for the duration of the pulse, and detecting the slope of the voltage across the load as a function of time and triggering the thyristor to conduction when the slope of the voltage function exceeds a preset value at a time when the timer is running. Alternatively, for use in an energy conserving pulse generator system, where the pulse current consists of half a period with a current running in one direction and half a period with the current running in the opposite direction, the pulse current can be sensed and the thyristor triggered to conduction if a shift of current direction occurs during a period of pulse decay.
Inventors
- 👤 Henrik Henriksen
- 👤 Torben Glar Nielsen
- 👤 Claus Ebbe Taarning
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 19:16
CPC Classifications
B; B03; B03C; B03C3/00; B03C3/34; B03C3/66; B03C3/68; H; H02; H02H; H02H7/00; H03; H03K; H03K17/00; H03K17/08; H03K17/082; H03K17/0824
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
50 words
A method of protecting a thyristor switch element (T) of a pulse generator supplying a capacitive load (C F ) characterized in that the thyristor or thyristors in the switch element is or are triggered to condution whenever a sparkover occurs in the load during a period of pulse decay.
Claim 2
Independent Claim
50 words
A method of protecting a thyristor switch element (T) of a pulse generator supplying a capacitive load (C F ) characterized in that the thyristor or thyristors in the switch element is or are triggered to condution whenever a sparkover occurs in the load during a period of pulse decay.
Claim 3
Dependent Claim
70 words
A method according to claim 1, characterized in that a timer (4) is started whenever a pulse starts, the timer (4) running for the duration of a pulse; the slope of the voltage across the load as a function of time is detected and the thyristor is triggered to conduction when the slope of the voltage function exceeds a preset value at a moment when the timer (4) is running.
Claim 4
Dependent Claim
83 words
A method according to claim 1 for use where the pulse generator is of the energy conserving type wherein the pulse current consists of a half period with the current running in one direction during the rise of the pulse and another half period with the current running in the opposite direction during pulse decay, characterized in that the pulse current is sensed (10) and the thyristor is triggered (9) to conduction if a shift of current direction occurs during the pulse decay.
Claim 5
Dependent Claim
70 words
An electrical pulse generator system for supplying a capacitive load, the system including apparatus for protecting a thyristor switch element (7) in the system from damage caused by sparkover across the load, the apparatus comprising means for detecting (6, 10) when a sparkover occurs across the load and for triggering (9) the thyristor or thyristors in the switch element to conduction when sparkover occurs during a period of pulse decay.
Claim 6
Dependent Claim
70 words
An electrical pulse generator system for supplying a capacitive load, the system including apparatus for protecting a thyristor switch element (7) in the system from damage caused by sparkover across the load, the apparatus comprising means for detecting (6, 10) when a sparkover occurs across the load and for triggering (9) the thyristor or thyristors in the switch element to conduction when sparkover occurs during a period of pulse decay.
Claim 7
Dependent Claim
72 words
A.system according to claim 4, including a timer (4) which is started whenever a pulse starts, the timer (4) running for the duration of a pulse; means (7) for detecting the slope of the voltage across the load as a function of time; and means (9) for triggering the thyristor(s) to conduction when the slope of the voltage function exceeds a preset value at a moment when the timer (4) is running.
Claim 8
Dependent Claim
81 words
A system according to claim 4 wherein the pulse generator is of the energy conserving type wherein the pulse current consists of a half period with the current running in one direction during the rise of the pulse and another half period with the current running in the opposite direction during pulse decay, including means (10) for sensing the pulse current and means (9) for triggering the thyristor(s) to conduction if a shift of current direction occurs during the pulse decay.
Claim 9
Dependent Claim
75 words
An electrostatic precipitator which incorporates an electrical pulse generator system for supplying a capacitive load to the precipitator, including apparatus for protecting a thyristor switch element (7) in the system from damage caused by sparkover across the precipitator, the apparatus comprising means for detecting (6, 10) when a sparkover occurs across the precipitator and-for triggering (9) the thyristor or thyristors in the switch element to conduction when sparkover occurs during a period of pulse decay.
Claim 10
Dependent Claim
75 words
An electrostatic precipitator which incorporates an electrical pulse generator system for supplying a capacitive load to the precipitator, including apparatus for protecting a thyristor switch element (7) in the system from damage caused by sparkover across the precipitator, the apparatus comprising means for detecting (6, 10) when a sparkover occurs across the precipitator and-for triggering (9) the thyristor or thyristors in the switch element to conduction when sparkover occurs during a period of pulse decay.
Claim 11
Dependent Claim
20 words
An electostatic precipitator according to claim 7 including an electrical pulse generator system according to claim 5 or claim 6.
References Cited (Backward Citations)
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