the motor trips and the Ground Fault LED illuminates until reset. If you selected warning (OFF), the Ground Fault LED flashes as long as the fault current exceeds the pickup level. Table 3.6 lists the pickup levels for each overload size. Ground fault protection is locked out for the overload class time.
Size | Pickup Current | Default Pickup |
| Range | Current |
| | |
1A | 1.5A | 1.5A |
| | |
1B | 2A to 5A | 5A |
| | |
1C | 2A to I FLC* | 5A |
2A | 2A to I FLC* | 10A |
2B | 2A to I FLC* | 10A |
3 | 2A to I FLC | 10A |
| * | |
4 | 2A to I FLC* | 10A |
5 | 5A to I FLC | 10A |
| * | |
6 | 10A to I FLC* | 20A |
*IFLC is the value of IFLC for OLR#2 if F3 is not set to OFF. If F3 is OFF, IFLC is the value of IFLC for OLR#1.
Table 3.6 Ground fault pickup levels
Ground fault detection requires no additional external circuitry or transformers. Ground fault detection for the SAMMS-LV device is not available for grounded, three-phase systems or single-phase applications. Ground fault pickup time is 360 msec.
3.25Autoreset After a Trip (SAMMS-LVX Only)
To restart the motor after a trip or a fault, you must first reset the SAMMS-LVX device. You can reset the SAMMS-LV device in one of two ways. First, press the Reset/Test button on the front panel of the device. Second, enable the autoreset with HHC function F8.
∙enable = ON
∙disable = OFF
With autoreset enabled, overload and external trips automati- cally reset in 30 seconds after the trip. Once the reset occurs, the SAMMS-LV device can be used to restart the motor, unless the motor has reached its maximum temperature and has not cooled down to the full-load level (start inhibit). Resetting after a trip does not interrupt or otherwise affect the ongoing motor thermal computations.
3.26 Emergency Restarting
In certain critical applications, you may want to restart a hot motor even though restarting will damage or destroy the motor. An emergency restart is a motor start that occurs after an overload trip on maximum allowable winding or housing tem- perature; but before they have cooled down to the full-load temperature level (100%) or below. In other words, an emer- gency restart is a start that occurs before the restart time displayed by HHC function F10 reaches zero.
With the emergency restart function enabled (HHC function F11), the motor can be restarted regardless of the residual heat. If the SAMMS-LV device performs an emergency restart, the winding and housing temperatures in the motor model compu- tations reset to zero. Any time the motor is started, whether an emergency restart or a normal start, the emergency restart HHC function F11 is automatically reset to disable.
∙enabled = ON
∙disabled = OFF
3.27Using the Hand Held Communicator (HHC)
The HHC provides you with the capability to monitor and alter various motor control and protection functions provided with the SAMMS-LV device. For example, you can monitor and alter control and protection settings such as on-delay time and overload class. You can also monitor a variety of motor operating conditions such as average current and elapsed running time.
The SAMMS-LV device functions accessible through the HHC are shown in Table 3.7 The number of functions available depends upon the model of the SAMMS-LV device you are using.
The HHC’s small size makes it convenient to carry around and use for communication with many SAMMS-LV devices. To use the HHC, connect the HHC’s cable, which uses a DB-9 connector, to the communication port located on the front panel of the SAMMS-LV device. The HHC receives power and control from the SAMMS-LV device. When connected to the SAMMS-LV device, data is displayed on the HHC by a four- character, seven segment liquid crystal display. When discon- nected from the SAMMS-LV device, the HHC does not retain or display data.
Once connected, you can access the functions provided by the SAMMS-LV device through the use of the HHC’s control keys. The HHC has five (5) control keys: (F)unction, LIST, UP, DOWN, and ENTER. The asterisk (*) key serves no function. The HHC control keys are described in the following sections.
