Transformer having a thyristor controlled circuit breaker

Claim 2

A transformer comprising: a magnetic core; a winding assembly inductively coupled to said magnetic core; a circuit breaker capable of interrupting power supplied by the transformer; electrical heat sensing means which is responsive to the temperature of said winding assembly; electrical control means which is responsive to said heat sensing means; and electromechanical tripping means which trips said circuit breaker when the temperature sensed by said heat sensing means exceeds a first predetermined value, said tripping means being activated by an electrical signal from said control means.

Claim 3

The transformer of claim 1 including a current sensing device which is responsive to the current flowing through a winding of the transformer, said current sensing device causing the control means to trip the circuit breaker when said current exceeds a predetermined value.

Claim 4

The transformer of claim 1 including overload signal means which is activated by the control means when the temperature sensed by the heat sensing means exceeds a second predetermined value.

Claim 5

The transformer of claim 1 wherein the electromechanical tripping means comprises a solenoid which is mechanically connected to a control release mechanism in the circuit breaker and is electrically connected to the electrical control means.

Claim 6

The transformer of claim 1 wherein the electrical heat sensing means comprises a temperature responsive variable resistance element located within the winding assembly.

Claim 7

The transformer of claim 1 wherein the electrical heat sensing means comprises a temperature responsive variable resistance element located adjacent to a lead carrying the load current, and a heat trap disposed around the resistance element and the lead, said heat trap having substantially the same heat time constant as the winding assembly.

Claim 8

The transformer of claim 2 wherein the current sensing device comprises a magnetic reed switch positioned substantially within the magnetic field of a current carrying member which conducts current from the winding assembly.

Claim 9

The transformer of claim 3 wherein the overload signal means comprises a lamp which is lighted by the control circuit when the temperature exceeds the second predetermined value.

Claim 10

The transformer of claim 3 wherein the control means comprises: first and second electrical heat sensors; a first switching circuit which activates the tripping means when the temperature monitored by the first heat sensor exceeds the first predetermined value; and a second switching circuit which activates the signal means when the temperature monitored by the second heat sensor exceeds the second predetermined value, said second switching circuit being capable of continuing to activate the signal means when the temperature monitored by the second heat sensor decreases below the second predetermined value.

Claim 11

The transformer of claim 9 wherein the first switching circuit includes means which permits changing the value of the first predetermined monitored temperature at which the circuiT breaker is tripped.

Claim 12

The transformer of claim 3 wherein the second predetermined value of temperature is less than the first predetermined value of temperature.

Claim 13

A transformer comprising: a magnetic core; a winding assembly inductively coupled to said magnetic core; a circuit breaker electrically connected between said winding assembly and a load; a first temperaure responsive variable resistance element located within said winding assembly; a second temperature responsive variable resistance element located within said winding assembly; an overload signal means which may be activated; a solenoid which trips said circuit breaker when activated; a magnetic reed switch located within the magnetic field of the current flowing through said circuit breaker; a first switching circuit which is responsive to the temperature monitored by said first variable resistant element, said first switching circuit activating said solenoid when the temperature monitored by said first variable resistant element exceeds a first predetermined value, said first switching circuit also activating said solenoid when the magnetic field surrounding said reed switch exceeds a predetermined value; means for changing the first predetermined value of temperature; a second switching circuit which is responsive to the temperature monitired by said second variable resistance element, said second switching circuit activating said signal means when the temperature monitiored by said second variable resistant element exceeds a second predetermined value and maintains activation of said signal means when the monitored temperature decreases below the second predetermined value until reset; and means for resetting said second switching circuit.

Claim 14

A transformer comprising: a magnetic core; a winding assembly inductively coupled to said magnetic core; a circuit breaker electrically connected between said winding assembly and a load; a first temperaure responsive variable resistance element located within said winding assembly; a second temperature responsive variable resistance element located within said winding assembly; an overload signal means which may be activated; a solenoid which trips said circuit breaker when activated; a magnetic reed switch located within the magnetic field of the current flowing through said circuit breaker; a first switching circuit which is responsive to the temperature monitored by said first variable resistant element, said first switching circuit activating said solenoid when the temperature monitored by said first variable resistant element exceeds a first predetermined value, said first switching circuit also activating said solenoid when the magnetic field surrounding said reed switch exceeds a predetermined value; means for changing the first predetermined value of temperature; a second switching circuit which is responsive to the temperature monitired by said second variable resistance element, said second switching circuit activating said signal means when the temperature monitiored by said second variable resistant element exceeds a second predetermined value and maintains activation of said signal means when the monitored temperature decreases below the second predetermined value until reset; and means for resetting said second switching circuit.