Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
395 words
A circuit arrangement for an uninterrupted switchover of a load between two different alternating current supply points at respective voltage levels, comprising: a first and a second circuit branch having inputs respectively connected to said supply points and having a common output connected to said load; a first and a second main switch respectively inserted between said common output and the inputs of said first and second branches; a first and a second collateral network respectively connected across said first and said second main switch, said first network including a first protective resistor, a first ancillary switch and a first pair of antiparallel thyristors in series with one another, said second network including a second protective resistor, a second ancillary switch and a second pair of antiparallel thyristors in series with one another, each thyristor having an anode, a cathode and a gate; a first disconnect switch inserted between the gates of the thyristors of said first pair; two first diodes each inserted between the gate and the cathode of one thyristor of said first pair with a polarity corresponding to that of the respectively other thyristor of said first pair for firing the latter thyristor in a closed state of said first disconnect switch upon application of voltage of a corresponding polarity across said first pair of thyristors; a second disconnect switch inserted between the gates of the thyristors of said second pair; two second diodes each inserted between the gate and the cathode of one thyristor of said second pair with a polarity corresponding to that of the respectively other thyristor of said second pair of firing the latter thyristor in a closed state of said second disconnect switch upon application of voltage of a corresponding polarity across said second pair of thyristors; and timing means operable during a switchover from one supply point to the other, with only the main switch of one branch initially closed and all other switches open, to control said switches in a sequence involving closure of the ancillary and disconnect switches of said one branch, opening of the main switch of said one branch, closure of the ancillary and disconnect switches of the other branch, opening of the disconnect and ancillary switches of said one branch, closure of the main switch of said other branch, and opening of the disconnect and ancillary switches of said other branch.
Claim 2
Dependent Claim
395 words
A circuit arrangement for an uninterrupted switchover of a load between two different alternating current supply points at respective voltage levels, comprising: a first and a second circuit branch having inputs respectively connected to said supply points and having a common output connected to said load; a first and a second main switch respectively inserted between said common output and the inputs of said first and second branches; a first and a second collateral network respectively connected across said first and said second main switch, said first network including a first protective resistor, a first ancillary switch and a first pair of antiparallel thyristors in series with one another, said second network including a second protective resistor, a second ancillary switch and a second pair of antiparallel thyristors in series with one another, each thyristor having an anode, a cathode and a gate; a first disconnect switch inserted between the gates of the thyristors of said first pair; two first diodes each inserted between the gate and the cathode of one thyristor of said first pair with a polarity corresponding to that of the respectively other thyristor of said first pair for firing the latter thyristor in a closed state of said first disconnect switch upon application of voltage of a corresponding polarity across said first pair of thyristors; a second disconnect switch inserted between the gates of the thyristors of said second pair; two second diodes each inserted between the gate and the cathode of one thyristor of said second pair with a polarity corresponding to that of the respectively other thyristor of said second pair of firing the latter thyristor in a closed state of said second disconnect switch upon application of voltage of a corresponding polarity across said second pair of thyristors; and timing means operable during a switchover from one supply point to the other, with only the main switch of one branch initially closed and all other switches open, to control said switches in a sequence involving closure of the ancillary and disconnect switches of said one branch, opening of the main switch of said one branch, closure of the ancillary and disconnect switches of the other branch, opening of the disconnect and ancillary switches of said one branch, closure of the main switch of said other branch, and opening of the disconnect and ancillary switches of said other branch.
Claim 3
Dependent Claim
42 words
A circuit arrangement as defined in claim 1 wherein said timing means is programmed to close the disconnect switch after closure of the ancillary switch and to open the ancillary switch after opening of the disconnect switch in each of said branches.
Claim 4
Dependent Claim
41 words
A circuit arrangement as defined in claim 1, further comprising a first and a second firing resistor respectively connected in series with said first and said second disconnect switch between the gates of said first and said second pair of thyristors.