Electronic control system for motors and the like
OwnerRolf A. Rostadinventor
Life of this patent
Estimating the term…
Abstract
A controller for a motor or like electrical equipment. A thyristor in series with a power conductor that feeds the equipment and a control circuit for activating the gate terminal of the thyristor in accordance with the operating conditions of the equipment. The control circuit includes a transformer having a secondary winding connected to the gate terminal and means for varying the current flow in the secondary winding according to load demands. A three phase system having a thyristor in each conductor and a transformer secondary winding for each thyristor, which windings are on a common core.
Claims3
A multi-level trip circuit for electrical loads having high unit current demands when they are connected to an electrical source for applying energy thereto comprising:
- electrical connection means for connecting a load to an electrical source, said electrical connection means including a controllable switch means for connecting and disconnecting said load to said electrical source;
- current sensing means associated with said electrical connection means operable to develop an electrical signal proportional to the instantaneous current passing through said electrical connection means;
- circuit means connected to receive said signal for said sensing means, said circuit means having at least a first resistance and a second resistance connected in series, arranged so said electrical signal passes serially therethrough;
- switching means connected across one of said first and second resistances operable to bypass one of said resistances when said switching means electrically conducts;
- a timing circuit connected to receive said electrical signal and connected to said switching means being operable to activate said switching means to bypass the resistance across which it is connected at a preselected time interval based on the level of said electrical signal;
- and
- a control means connected to the output of said circuit means and to said controllable switch means operable to cause said switch means to dissconnect said load from said electrical source when said electrical signal exceeds predetermined levels whereby a higher initial current can be drawn by said load for a preselected time interval without causing said switch means to disconnect the load and thereafter a lower current level will cause the switch means to disconnect the load after the preselected time interval has been exceeded.
Dependencies are inferred from the claim text.