Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
229 words
A system for protecting a multi-phase alternating current motor from current overload comprising: a current transformer coupled to each of said phases of said motor, means for connecting the output of each of said transformers to a summing point, a differential amplifier connected to said summing point for detecting the occurrence of a current overload on any of said phases, a digital circuit connected to said amplifier for generating a logic level in dependence upon the output of said amplifier, a normally conductive field effect transistor coupled to said digital circuit for becoming nonconductive upon the occurrence of a current overload, a capacitor connected to said field effect transistor, a pair of normally nonconductive transistors coupled to said field effect transistor, one of said pair of transistors coupled to said capacitor in order to initiate a timing cycle before said field effect transistor may be again rendered conductive after the occurrence of a current overload, a first light emitting device, the other of said pair of transistors operable to energize said first light emitting device to indicate the occurrence of said timing cycle, a triac, switch means for normally maintaining said triac in conduction and operable in response to the occurrence of a current overload to render said traic nonconductive, and relay means operable by said triac to terminate current flow through said phases when said triac is nonconductive.
Claim 2
Independent Claim
229 words
A system for protecting a multi-phase alternating current motor from current overload comprising: a current transformer coupled to each of said phases of said motor, means for connecting the output of each of said transformers to a summing point, a differential amplifier connected to said summing point for detecting the occurrence of a current overload on any of said phases, a digital circuit connected to said amplifier for generating a logic level in dependence upon the output of said amplifier, a normally conductive field effect transistor coupled to said digital circuit for becoming nonconductive upon the occurrence of a current overload, a capacitor connected to said field effect transistor, a pair of normally nonconductive transistors coupled to said field effect transistor, one of said pair of transistors coupled to said capacitor in order to initiate a timing cycle before said field effect transistor may be again rendered conductive after the occurrence of a current overload, a first light emitting device, the other of said pair of transistors operable to energize said first light emitting device to indicate the occurrence of said timing cycle, a triac, switch means for normally maintaining said triac in conduction and operable in response to the occurrence of a current overload to render said traic nonconductive, and relay means operable by said triac to terminate current flow through said phases when said triac is nonconductive.
Claim 3
Dependent Claim
29 words
The system of claim 1 wherein said switch means comprises: a pair of intercoupled normally conductve transistors responsive to the occurrence of a current overload to be rendered nonconductive.
Claim 4
Dependent Claim
45 words
The system of claim 2 and further comprising: a second light emitting device, and a normally nonconductive transistor responsive to one of said pair of normally conductive transistors in order to energize said second light emitting device to indicate the occurrence of a current overload.
Claim 5
Dependent Claim
26 words
The system of claim 1 and further comprising: means responsive to the operation of an interlock circuit on said motor to visually indicate an interlock malfunction.
Claim 6
Dependent Claim
17 words
The system of claim 1 wherein said triac is powered from one of said alternating current phases.