Compliant, hazardous environment circuit protection devices, systems and methods

Patent metadata

Field	Value
Publication number	US-11527882-B2
Application number	US-202117566360-A
Country	US
Kind code	B2
Filing date	Dec 30, 2021
Priority date	Dec 26, 2018
Publication date	Dec 13, 2022
Grant date	Dec 13, 2022

Abstract

Solid state and hybrid circuit protection devices include improved arc-less switching capability and overcurrent protection, improved terminal assemblies and improved thermal management features that reduce or eliminate ignition sources for hazardous environments. The solid state and hybrid circuit protection devices are ignition protected and avoid possible explosions and therefore obviate a need for conventional explosion-proof enclosures to ensure safe operation of an electrical power system in a hazardous location.

First claim

What is claimed is:

1. An ignition protected switch device comprising:
a housing;
a line-side terminal and a load-side terminal coupled to the housing;
a bus structure in the housing and including at least one solid state switching element operable in an arc-free manner to connect the load-side terminal to the line-side terminal and disconnect the load-side terminal from the line-side terminal; and
a controller operating the at least one solid state switching element in reference to a first operating temperature limit for the bus structure, thereby precluding the operating bus structure from being an ignition source in a hazardous location, whereby the ignition protected switch device is compliant for use in the hazardous location without requiring a separately provided explosion-proof enclosure; and
a toggle switch, wherein the controller is further configured to operate the at least one solid state switching element in response to the toggle switch.

2. The ignition protected switch device of claim 1 , wherein the line-side terminal and the load-side terminal each comprise a secure cable terminal assembly including a locking element preventing a cable termination from loosening over time when subjected to thermal cycling or vibration, thereby precluding the secure terminal assembly from being an ignition source in the hazardous location.

3. The ignition protected switch device of claim 2 , wherein the secure cable terminal assembly further includes a lug terminal and wherein the locking element is a spring element.

4. The ignition protected switch device of claim 3 , wherein the lug terminal further comprises a fastener, and wherein the spring element acts upon the fastener to prevent the cable termination from loosening.

5. The ignition protected switch device of claim 4 , wherein the lug terminal is a box lug, and wherein the spring element acts internally to the box lug.

6. The ignition protected switch device of claim 4 , wherein the spring element is one of a coil spring or a spring plate.

7. The ignition protected switch device of claim 3 , wherein the secure terminal assembly further comprises a lever, the spring element acting on an end of the lever.

8. The ignition protected switch device of claim 1 , wherein the line-side terminal and the load-side terminal comprises either a plug or socket which connects to a cable.

9. The ignition protected switch device of claim 8 , wherein the plug or socket provides a reject feature for an incompatible switch device.

10. The ignition protected switch device of claim 8 , wherein the controller is further configured to operate the at least one solid state switching element to effect a hot swap feature for the ignition protected switch device.

11. The ignition protected switch device of claim 1 , further comprising a display.

12. The ignition protected switch device of claim 1 , further comprising an active cooling element.

13. The ignition protected switch device of claim 1 , further comprising a passive cooling element.

14. The ignition protected switch device of claim 1 , further comprising a varistor connected in parallel to the at least one solid state switching element.

15. The ignition protected switch device of claim 1 , wherein the controller is further configured to provide motor starter and overload control.

16. The ignition protected switch device of claim 1 , wherein the device is configured as a solid state circuit breaker.

17. The ignition protected switch device of claim 1 , wherein the hazardous location is an NEC Division 2 or IEC Zone 1 location.

18. An ignition protected switch device for a hazardous location with airborne flammable gas or vapor in an amount sufficient to produce an explosive mixture, the ignition protected switch device comprising:
a housing;
a line-side terminal and a load-side terminal coupled to the housing;
a bus structure in the housing, the bus structure including at least one solid state switching element, the at least one solid state switching element being operable in an arc-free manner to selectively conduct current between the line-side terminal and the load-side terminal or to preclude current flow between the line-side terminal and the load-side terminal and therefore electrically isolate the load-side terminal from the line-side terminal; and
a controller operating the at least one solid state switching element to maintain an operating temperature of the ignition protected switch device below a rated temperature for the hazardous location in order to preclude the operating temperature from being an ignition source, whereby the ignition protected switch device is compliant for use in the hazardous location without requiring a separately provided explosion-proof enclosure; and
a toggle switch, wherein the controller is further configured to operate the at least one solid state switching element in response to the toggle switch.

19. A switch device for an NEC Division 2 or IEC Zone 1 location, the switch device comprising:
a housing;
a line-side terminal and a load-side terminal coupled to the housing;
a bus structure in the housing and including at least one semiconductor switch operable electronically to conduct current from the load-side terminal to the line-side terminal or to isolate the load-side terminal from the line-side terminal; and
a controller operating the at least one semiconductor switch to avoid an operating temperature of the ignition protected switch device exceeding a rated temperature for the NEC Division 2 or IEC Zone 1 location, thereby precluding the operating temperature from being an ignition source in the NEC Division 2 or IEC Zone 1 location and rendering the switch device compliant for use in the NEC Division 2 or IEC Zone 1 location without requiring a separately provided ignition-proof enclosure; and
a toggle switch, wherein the controller is further configured to operate the at least one solid state switching element in response to the toggle switch.

Assignees

• Eaton Intelligent Power Ltd

Inventors

• Manahan Joseph Michael
• Ledgerwood Adam
• Butler Andrew
• Decarr Graig
• Leubner Edmund

Classifications

• H01H2009/544

  the static switching means being an insulated gate bipolar transistor, e.g. IGBT, Darlington configuration of FET and bipolar transistor · CPC title

• H01H1/5855

  characterised by the use of a wire clamping screw or nut · CPC title

• H02H3/0935

  the timing being determined by numerical means · CPC title

• H01H9/52

  Cooling of switch parts (cooling of contacts H01H1/62) · CPC title

• H02H3/027

  with automatic disconnection after a predetermined time (H02H3/033, H02H3/06 take precedence {; timing in overcurrent protection circuits H02H3/093; in undervoltage protection circuits H02H3/247; staggered disconnection H02H7/30}) · CPC title