LV Breaker - Phase Trip Tab

This option is only available after you set the Trip and Solid State Trip fields on the Specifications tab.

You can also select or clear it in the Temporary Thermal Magnetic Data dialog box in Coordination mode to avoid plotting the TCC.

When this check box is selected, the program automatically scales the TCC curves based on the phase connection type. Traditionally, for 3PH curves in a TCC, scaling the curves based on the reference voltage is adequate. If a line-to-neutral connected 1PH device is to be plotted with an upstream 3PH device, then the LN connected 1PH curve needs to be shifted by a factor of the SQRT(3) in addition to the voltage-based scaling. Similarly, if a line-to-neutral connected 1PH device is to be plotted with an upstream 1PH-3W device, then the LN connected 1PH curve needs to be shifted by a factor of the 2 in addition to the voltage-based scaling.

When the check box is not selected, scaling based on the phase connection type is not applied.

The check box status for individually stored TCC plots can be different. The default for new TCC plots is obtained from the database for the device.

This message shows the manufacturer (Mfr), Type and Style of low voltage breaker that was selected.

Click to view notes recorded in the library for the device. Information may include data sheets or manufacturer's information for the device or assumptions needed to model the device.

Frame description. This may be the frame size, the largest rating in the range of similar models, or a range of sizes that have similar curves.

Nominal rated amps the device is rated to carry without tripping.

For solid state trip devices, this field can be selected to plot TCC or cleared to avoid plotting the TCC of the phase trip characteristics. To obtain a TCC plot of a Ground Trip only, clear this check box.

When this check box is selected, the program automatically scales the TCC curves based on the phase connection type. Traditionally, for 3PH curves in a TCC, scaling the curves based on the reference voltage is adequate. If a line-to-neutral connected 1PH device is to be plotted with an upstream 3PH device, then the LN connected 1PH curve needs to be shifted by a factor of the SQRT(3) in addition to the voltage-based scaling. Similarly, if a line-to-neutral connected 1PH device is to be plotted with an upstream 1PH-3W device, then the LN connected 1PH curve needs to be shifted by a factor of the 2 in addition to the voltage-based scaling.

When the check box is not selected, scaling based on the phase connection type is not applied.

The check box status for individually stored TCC plots can be different. The default for new TCC plots is obtained from the database for the device.

This section shows the kind of trip unit selected and other descriptions of device selected in the Specifications tab such as the manufacturer (Mfr), Type, Style, Sensor rating, and Plug/Trip value of the trip unit.

The long time pickup and delay are selected in this section. The pickup calculation depends on the device selected. It may include LTPU Mult, but it will include Setting (C) and either Sensor or Plug/Tap. After the settings are selected, the actual pickup in amperes appears in parentheses.

• Setting (C): The long time pickup current setting below which the device will not trip. This is a fraction of the sensor or plug/tap amps. For some trip units LTPU multiple may also be required to set the pickup current.

  LTPU Mult: Multiple of Setting (C), which can be adjusted to “fine-tune” the long time pickup setting. Some trip units may not have this feature.

  Curve: Some solid state curves may have multiple LT delay curves to choose from. This field enables you to choose the curve shape.



Figure 3: LT Delay Curve

• LT Delay: Long time delay setting to select the delay band.

Short time pickup and delay settings. This section is applicable to only devices with short time trip. After the settings are selected, the actual pickup in amperes appears in parentheses.

• Pickup: The short time pickup current setting below which the device will not trip for short time trip. The short time pickup setting may be a multiple of long time pickup, sensor rating, plug or tap value, or the current setting times the sensor or plug/tap.
• (I^x)t: To select shape and slope of delay short time band. When you select In, the (I^x)t function is enabled. The delay band has a slope of minus “x”. When you select Out, the (I^x)t function is unavailable, and the short time delay is independent of the current. For some new circuit breakers, the (I^x)t delay may be adjustable. In such cases, the choices available will be the various possible delay settings.
• Delay: Short time delay setting to select the delay band.

Nominal instantaneous trip amps, multiple, or pickup setting. When you highlight or select a choice, the corresponding trip amps appear in parenthesis.

• Enable Override: Selecting this option disables tripping based on pickup setting. The device trips at an override value that depends on the device style. This feature may or may not be applicable to the device selected.
• Pickup: The instantaneous trip pickup setting.

This check box is only available if the Trip and Solid State Trip settings are selected on the Specifications tab.

When this check box is selected, the program automatically scales the TCC curves based on the phase connection type. Traditionally, for 3PH curves in a TCC, scaling the curves based on the reference voltage is adequate. If a line-to-neutral connected 1PH device is to be plotted with an upstream 3PH device, then the LN connected 1PH curve needs to be shifted by a factor of the SQRT(3) in addition to the voltage-based scaling. Similarly, if a line-to-neutral connected 1PH device is to be plotted with an upstream 1PH-3W device, then the LN connected 1PH curve needs to be shifted by a factor of the 2 in addition to the voltage-based scaling.

When the check box is not selected, scaling based on the phase connection type is not applied.

The check box status for individually stored TCC plots can be different. The default for new TCC plots is obtained from the database for the device.

This message shows the kind of trip unit selected and other descriptions of the device selected in the Specifications tab such as the manufacturer (Mfr), Type and Style of low voltage circuit breaker.

Frame and Trip descriptions.

• Frame: This may be the frame size, the largest rating in the range of similar models, or a range of sizes that have similar curves.
• Trip: Nominal rated amps the breaker is rated to carry without tripping.

The long time pickup and delay are selected in this section. After the settings are selected, the actual pickup in amperes appears in parentheses.

• Setting: The long time pickup setting below which the device will not trip. This is a multiple of the Trip amps or the trip unit rating.
• Band: Long time delay band to adjust the delay.

Short time pickup and delay settings. This section is applicable to only devices with short time trip. After the settings are selected, the actual pickup in amperes appears in parentheses.

• Setting: The short time pickup setting below which the device will not trip for short time delay. This is a multiple of the long time pickup.
• Band: Short time delay band to adjust the delay.