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US 4,376,913 AGranted
Method and apparatus for synchronously driving AC synchronous motors
AssigneeHorix Manufacturing Company
InventorBernard I. Higby
Life of this patent
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AssigneeHorix Manufacturing Company
InventorBernard I. Higby
Estimating the term…
A plurality of AC synchronous motors used to drive respective machines in a manufacturing or packaging assembly line or system are driven in speed and phase synchronization. A common AC current supply signal is inverted to provide one polyphase set of series of controlled frequency low voltage DC pulses in a lead inverter. This polyphase set of pulses are amplified and utilized to drive the AC synchronous motor for the lead machine in the system. This same set of polyphase pulses are also transmitted directly to follower inverters respectively and there amplified to drive respective synchronous motors in the system to not only insure speed synchronization but also absolute phase synchronization in driving all machines in the line. When the frequency of the polyphase set of pulses is varied to correspondingly drive the AC synchronous motors at predetermined speeds, phase synchronization of the motors will always be insured. The AC synchronous motor drives are further adapted to automatically position all of the machines in the line to their respective start positions for position synchronization of the line through the use of position sensors on each machine.
In a manufacturing or packaging assembly line system having a plurality of machines driven by respective AC synchronous motors and adapted to sequentially conduct successive steps of manufacture or packaging on articles moving in the assembly line, a drive control for synchronously driving said AC synchronous motors, said drive control including a plurality of AC inverters having polyphase variable frequency output signals consisting of polyphase sets of series of controlled frequency low voltage DC pulses which are amplified to respectively drive said motors at synchronized speeds, the improvement comprising circuit means in one of said inverters for generating one of said low voltage polyphase DC pulse sets and for transmitting said one low voltage polyphase DC pulse set to the remaining inverters for respective amplification by all inverters to thereby provide said respective polyphase output signals with positive phase synchronization.
The drive control of claim 5, wherein said logic circuit means includes means to drive said motors and then automatically brake and hold each motor when its corresponding machine attains position synchronization as sensed by said position sensors until all machines are in position synchronization.
A method of synchronously driving a plurality of AC synchronous motors in phase synchronization in a manufacturing or packaging assembly line having a plurality of machines respectively driven by the motors, comprising the steps of, inverting an AC current supply with a plurality of AC inverters corresponding in number to the plurality number of said motors to be driven to thereby provide a corresponding plurality of polyphase variable frequency output signals respectively from said inverters consisting of amplified polyphase sets of series of low voltage DC pulses, and respectively driving said motors with said amplified polyphase sets of pulses, the improvement comprising the steps of generating one of said low voltage polyphase DC pulse sets in one of the inverters, and transmitting said one low voltage polyphase DC pulse set to the remaining inverters for respective amplification by all inverters to thereby provide said respective amplified polyphase output signals with positive phase synchronization.
Dependencies are inferred from the claim text.