Three phase surge protection device

1. A three phase surge protection device comprising:

a stack comprising a first varistor, a second varistor and a third varistor, wherein the varistors are electrically connected to form a circuit; and

a first thermal disconnect configured to interrupt the circuit when a temperature of the first thermal disconnect exceeds a predefined temperature,

wherein the first thermal disconnect comprises a first spring member and a first slider,

wherein the first spring member is soldered to a first terminal of the stack by a low temperature solder joint,

wherein the first thermal disconnect is configured such that the first slider abuts a first abutment face of the first spring member when the first spring member is fixed to the first terminal of the stack by the low temperature solder joint such that the first slider does not apply pressure to the low temperature solder joint, and

wherein the first abutment face of the first spring member is perpendicular to the low temperature solder joint when the low temperature solder joint is closed.

2. The three phase surge protection device according to claim 1 , wherein the first thermal disconnect is configured to interrupt the circuit when the low temperature solder joint melts.

3. The three phase surge protection device according to claim 1 , wherein the predefined temperature is a melting temperature of the low temperature solder.

4. The three phase surge protection device according to claim 1 ,

wherein the first thermal disconnect is configured such that the first slider triggers a micro switch when the low temperature solder joint between the first spring member and the first terminal of the stack melts due to an overheating of at least one of the first varistor or the third varistor.

5. The three phase surge protection device according to claim 4 , wherein the micro switch is configured to indicate an interruption of the circuit.

6. The three phase surge protection device according to claim 4 , wherein the first thermal disconnect further comprises a first spring which is biased when the low temperature solder joint is closed and which is configured to move the first slider when the low temperature solder joint melts.

7. The three phase surge protection device according to claim 1 , further comprising a second thermal disconnect configured to interrupt the circuit when a temperature of the second thermal disconnect exceeds a predefined temperature.

8. The three phase surge protection device according to claim 7 , wherein the first thermal disconnect and the second thermal disconnect are independent from each other.

9. The three phase surge protection device according to claim 7 , wherein the second thermal disconnect comprises a second spring member, and wherein the second spring member is soldered to a second terminal of the stack by a low temperature solder joint.

10. The three phase surge protection device according to claim 9 ,

wherein the second thermal disconnect comprises a second slider, and

wherein the second thermal disconnect is configured such that the second slider triggers a micro switch when the low temperature solder joint between the second spring member and the second terminal of the stack melts due to an overheating of at least one of the second varistor or the third varistor.

11. The three phase surge protection device according to claim 7 , further comprising a module housing, wherein the stack, the first thermal disconnect and the second thermal disconnect are arranged inside the module housing.

12. The three phase surge protection device according to claim 7 ,

wherein the first terminal of the stack is connected to the first varistor and to the third varistor,

wherein a second terminal of the stack is connected to the second varistor and to the third varistor,

wherein the stack has a third terminal connected to the first varistor and to the second varistor,

wherein the first terminal of the stack is connected to one end of the first spring member by a low temperature solder joint and wherein an opposing end of the first spring member forms a first male connector of the three phase surge protection device,

wherein the second terminal of the stack is connected to one end of a second spring member by a low temperature solder joint and wherein the opposing end of the a second spring member forms a second male connector of the three phase surge protection device, and

wherein the third terminal forms a third male connector of the three phase surge protection device.