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US 4,897,755 AGranted
Apparatus and method for relay control
AssigneeLouis S. Polster
InventorsLouis S. Polster, Ronald R. Flinders
Life of this patent
Estimating the term…
Abstract
Where there is a relay controlling an AC power circuit to a load, the apparatus of this disclosure includes a sensor for observing arc at the relay contacts and a control circuit which controls the time of subsequent actuation or deactuation of the relay with respect to the alternating current power circuit so as to eliminate relay contact arcing.
Claims22
An apparatus for the control of
- a relay having relay contacts, comprising:
- a control circuit;
- command signal connection means forming part of said control circuit for receiving a signal signalling the actuation of a relay;
- energization connection means forming part of said control circuit for connection to a relay for opening or closing the contacts of the relay;
- observation means for observing electric arcing occurring during opening or closing of the relay contacts;
- adjustment means forming part of said control circuit for controlling the energization point of said energization connection means, said observation means being connected to said adjustment means for adjusting said adjustment means so that the relay contacts open or close during a substantially zero current through the relay contacts.
3 more elements
An apparatus for relay control comprising:
- a control circuit;
- operating means connected to said control circuit for causing the opening of relay contacts in an AC line;
- an arc sensor positioned with respect to the relay contacts to detect arcing emissions resulting from opening of the relay contacts when current is passing therethrough, said arc sensor being connected to said control circuit to signal arcing to said control circuit;
- a zero voltage sensing circuit connected to the AC line and connected to said control circuit to provide a time reference for the AC line to said control circuit;
- and
- command signal means connected to said control circuit to signal the opening of the relay contacts, said control circuit being connected so that when a relay opening command signal is received and said control circuit causes opening of said relay contact and an arc is detected, said control circuit is adjusted to cause relay operation to open the relay contacts at a different point on the current cycle on subsequent actuation so that, upon subsequent relay opening, the control circuit is adjusted so that the relay contacts open at a zero current point on the AC cycle and no arcing is detected.
3 more elements
The method of controlling a relay which
- has contacts for connection into an AC load line and which has an actuation device for controlling the contacts, comprising the steps of:
- detecting the alternating voltage state at the point along the AC cycle at which the relay contacts are opened;
- observing radiation at the opening of the contacts and when there is radiation;
- adjusting the time of relay opening with respect to the AC wave to a different point on the AC wave so that the relay arcing radiation is minimized to enhance contact life.
1 more element
Dependencies are inferred from the claim text.