Automatic power bus transfer equipment
First Claim
1. A high speed transfer circuit utilized with a first power source connectable in series with a load through a first set of switchable contacts, and a second power source connectable to the load through a second set of switchable contacts to effect a high speed transfer of the load between the first and second power sources, comprising:
- a first and second solid state switch connected respectively across the first and second switchable contacts;
a timer circuit driving said first solid state switch into conduction before said first switchable contacts are operated, said timer circuit removing said drive from said first solid state switch after said first switchable contacts have been operated, and substantially simultaneously with the removal of the drive from said first solid state switch, said timer circuit drives said second solid state switch into conduction so that said second power source is connected to the load, said timer circuit being operative to remove said drive from said second solid state switch after said second switchable contacts have been operated; and
inhibit means for inhibiting timer circuit from driving said solid state switches concurrently.
1 Assignment
0 Petitions
Accused Products
Abstract
A circuit for protecting the power contacts (18, 20) of automatic bus transfer equipment, including high speed solid state switches (30, 32) connected across the respective contacts. A timing and steering circuit (36) is responsive to the electrical energization of a solenoid (22) for firing the solid state switch (32) connected across the closed contact (18). A timer (48) is responsive to the opening of the contacts (18). At the elapse of a time period, the firing circuit (34) is caused to operate the solid state switch (30) before the closing of the contacts (20). The solid state switch (30) is maintained operated for a predetermined period of time by a timer (90).
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Citations
25 Claims
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1. A high speed transfer circuit utilized with a first power source connectable in series with a load through a first set of switchable contacts, and a second power source connectable to the load through a second set of switchable contacts to effect a high speed transfer of the load between the first and second power sources, comprising:
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a first and second solid state switch connected respectively across the first and second switchable contacts; a timer circuit driving said first solid state switch into conduction before said first switchable contacts are operated, said timer circuit removing said drive from said first solid state switch after said first switchable contacts have been operated, and substantially simultaneously with the removal of the drive from said first solid state switch, said timer circuit drives said second solid state switch into conduction so that said second power source is connected to the load, said timer circuit being operative to remove said drive from said second solid state switch after said second switchable contacts have been operated; and inhibit means for inhibiting timer circuit from driving said solid state switches concurrently. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A timer circuit controlling a high speed switchover between a generally noninductive load and first and second power sources, said timer circuit protecting a first and second solenoid operated contacts carrying electrical energy and of the type where one of the contacts is open and associated with the first power source, while the other contact is closed and associated with the second power source, comprising:
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a solenoid operable to control the opening and closing of said first and second contacts; a first solid state switch connected across said first contact; a second solid state switch connected across said second contact; first means for driving said first solid state switch; second means for driving said second solid state switch; signal generating means responsive to the energization of said solenoid for generating a signal for triggering said first solid state switch; means responsive to the opening of the first contact for removing the triggering of said first solid state switch and for substantially simultaneously triggering said second solid state switch such that a high speed switchover between the first and second power sources is effected; and means for removing the triggering of said second solid state switch after the second contacts have been closed. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A timer circuit protecting a first and second solenoid operated mechanical contact carrying electrical energy, and of the type where one of the contacts is open while the other is closed, and of the type having subsidiary contacts associated with the main contacts, comprising:
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a solenoid operable to control the opening and closing of said first and second contacts; a first and second solid state switch, each connected across a respective one said first or second main contacts; pulse forming means responsive to the energization of said solenoid for generating a pulse; a first timing and steering circuit and a substantially functional identical second timing and steering circuit, each said timing and steering circuit being associated withone said first or second solid state switch; said first timing and steering circuit comprising a logic gate with an input connected to one said subsidiary contact and an input connected to said pulse forming means; a latch responsive to an output of said logic gate; a first timer responsive to the output of said latch for generating an output pulse of a predetermined width; a driver responsive to the output of said first timer for driving said first solid state switch; and a second timer for generating a first and second time period in response to the actuation of the other said subsidiary contact to actuate said latch to thereby drive said first solid state switch. - View Dependent Claims (19, 20, 21, 22)
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23. A method providing a high speed transfer between a load and a first and second AC power supplies, and providing contact protection for a bus transfer system having a pair of solenoid operated contacts arranged so that one contact which is associated with the first power source and the load is open when the other contact which is associated with the second power source and the load is closed, comprising the steps of:
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detecting an electrical energization of a solenoid associated with the pair of contacts, and in response thereto establishing a first conductive path around the closed contact before the closed contact begins to open; detecting the opening of the closed contact; removing said first conductive path in response to the detection of the opening of the closed contact and substantially simultaneously establishing a second conductive path around the open contact before the open contact closes; and maintaining the second conductive path for a predetermined period of time and thereafter removing said second conductive path. - View Dependent Claims (24, 25)
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Specification