# US 2021/0242676 A1 · Arc fault detection in transport refrigeration unit

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- Number: US 2021/0242676 A1
- Document ID: US20210242676A1
- Status: Published application
- Kind: A1
- Application number: 16/972,159
- Filed: 2019-08-05
- Published: 2021-08-05
- Earliest claimed: 2018-08-08
- Assignees: Carrier Corporation
- Applicants: Carrier Corporation
- Inventors: Michael Stockbridge; William F. Caswell
- Web page: https://patentgrep.com/patent/US20210242676A1

## CPC

- H02H 1/0015: {Using arc detectors}
- B60H 1/00428: {electric}
- B60H 1/3232: {particularly adapted for load transporting vehicles (B60H1/3226 takes precedence)}
- F25D 11/003: {Transport containers}
- F25D 29/003: {for movable devices}
- Y02T 10/88: Optimized components or subsystems, e.g. lighting, actively controlled glasses
- H02H: EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS (indicating or signalling undesired working conditions G01R, e.g. G01R31/00, G08B; locating faults along lines G01R31/08; emergency protective devices H01H)
- B60H: ARRANGEMENTS OF HEATING, COOLING, VENTILATING OR OTHER AIR-TREATING DEVICES SPECIALLY ADAPTED FOR PASSENGER OR GOODS SPACES OF VEHICLES
- F25D: REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR (refrigerated showcases A47F3/04; thermally-insulated vessels for domestic use A47J41/00; refrigerated vehicles, see the appropriate subclasses of classes B60 - B64; containers with thermal insulation in general B65D81/38; heat-transfer, heat-exchange or heat-storage materials, e.g. refrigerants, or materials for the production of heat or cold by chemical reactions other than by combustion C09K5/00; thermally-insulated vessels for liquefied or solidified gases F17C; air-conditioning or air-humidification F24F; refrigeration machines, plants, or systems F25B; cooling of instruments or comparable apparatus without refrigeration G12B)
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A cargo (22) detection system for a refrigerated cargo container (10) includes a cargo sensor (50) body configured to detect presence of cargo (22) in a refrigerated cargo container (10) and a sensor bracket (56) configured for securing the cargo sensor (50) body at a refrigeration unit (24) of the refrigerated cargo container (10). A temperature sensor (72) is located at the cargo sensor (50) body and is configured to detect a temperature of the cargo sensor (50) body. A temperature controller (74) is operably connected to the temperature sensor (72) and is configured to activate the cargo sensor (50) body for collection of data when the temperature of the cargo sensor (50) body is above a threshold.

## Claims

### Claim 1

A method for detecting an electrical arc fault in a transport refrigeration unit, the method comprising:
monitoring a parameter of a power source powering the transport refrigeration unit;
determining a magnitude of a high frequency component of the parameter of the power source;
comparing the high frequency component of the parameter of the power source to a threshold; and
determining that the electrical arc fault is present when the high frequency component of the parameter of the power source exceeds the threshold.

### Claim 2 (depends on 1)

The method of claim 1, further comprising:
monitoring a system parameter of the transport refrigeration unit; and
setting the threshold in response to the system parameter.

### Claim 3 (depends on 2)

The method of claim 2, wherein:
the system parameter comprises a DC current;
wherein setting the threshold comprises increasing the threshold when a DC current is present.

### Claim 4 (depends on 2)

The method of claim 2, wherein:
the system parameter comprises active AC loads;
wherein setting the threshold comprises increasing the threshold when an active AC load is present.

### Claim 5 (depends on 2)

The method of claim 2, wherein:
the system parameter comprises type of power source;
wherein setting the threshold comprises increasing the threshold when the type of power source indicates a likelihood of high frequency components.

### Claim 6 (depends on 3)

The method of claim 3, wherein:
increasing the threshold comprises increasing a reference threshold by a predetermined first amount.

### Claim 7 (depends on 1)

The method of claim 1, further comprising:
determining if a load on the power source has changed within a time frame;
wherein when the load on the power source has changed within the time frame, then terminating the detecting of the electrical arc fault.

### Claim 8 (depends on 1)

The method of claim 1, wherein:
the threshold comprises a magnitude component.

### Claim 9 (depends on 1)

The method of claim 1, wherein:
the threshold comprises a magnitude component and a time component.

### Claim 10

A transport refrigeration unit comprising:
a power source;
a compressor, a condenser fan motor and an evaporator fan motor, at least one of the compressor, the condenser fan motor and the evaporator fan motor powered by the power source;
a sensor to monitor a parameter of the power source;
a controller in communication with the sensor, the controller configured to execute operations comprising:
monitoring a parameter the power source powering the transport refrigeration unit;
determining a magnitude of a high frequency component of the parameter of the power source;
comparing the high frequency component of the parameter of the power source to a threshold; and
determining that the electrical arc fault is present when the high frequency component of the parameter of the power source exceeds the threshold.

### Claim 11 (depends on 10)

The transport refrigeration unit of claim 10, wherein the operations further comprise:
monitoring a system parameter of the transport refrigeration unit; and
setting the threshold in response to the system parameter.

### Claim 12 (depends on 11)

The transport refrigeration unit of claim 11, wherein:
the system parameter comprises a DC current;
wherein setting the threshold comprises increasing the threshold when a DC current is present.

### Claim 13 (depends on 11)

The transport refrigeration unit of claim 11, wherein:
the system parameter comprises active AC loads;
wherein setting the threshold comprises increasing the threshold when an active AC load is present.

### Claim 14 (depends on 11)

The transport refrigeration unit of claim 11, wherein:
the system parameter comprises type of power source;
wherein setting the threshold comprises increasing the threshold when the type of power source indicates a likelihood of high frequency components.

### Claim 15 (depends on 12)

The transport refrigeration unit of claim 12, wherein:
increasing the threshold comprises increasing a reference threshold by a predetermined first amount.

### Claim 16 (depends on 10)

The transport refrigeration unit of claim 10, further comprising:
determining if a load on the power source has changed within a time frame;
wherein when the load on the power source has changed within the time frame, then terminating the detecting of the electrical arc fault.

### Claim 17 (depends on 10)

The transport refrigeration unit of claim 10, wherein:
the threshold comprises a magnitude component.

### Claim 18 (depends on 10)

The transport refrigeration unit of claim 10, wherein:
the threshold comprises a magnitude component and a time component.