Siemens SAMMS-MV Manual De Usuario

3 Operating the SAMMS-MV Device

Size

Pickup Current

Range

Default Pickup

Current

H3A

7A to I

10A

H3B

7A to I

10A

H3C

7A to I

10A

7A to I

20A

Table 3.6 Ground fault pickup levels

Ground fault detection requires no additional external circuitry

or transformers. Ground fault detection for the SAMMS-MV

device is not available for grounded, three-phase systems or

single-phase applications. Ground fault pickup time is 360

msec.

3.26 Autoreset After a Trip (SAMMS-MVX

Only)

To restart the motor after a trip or a fault, you must first reset the

SAMMS-MVX device. You can reset the SAMMS-MV 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-MV 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.

3.27 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, housing, or rotor

temperature; but before all 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-MV device performs an emergency restart, the

winding, housing, and rotor temperatures in the motor model

computations 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

3.28 Using 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-MV 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-MV device functions accessible through the HHC

are shown in Table 3.7 The number of functions available

depends upon the model of the SAMMS-MV device you are

using.

The HHCs small size makes it convenient to carry around and

use for communication with many SAMMS-MV devices. To use

the HHC, connect the HHCs cable, which uses a DB-9

connector, to the communication port located on the front

panel of the SAMMS-MV device. The HHC receives power and

control from the SAMMS-MV device. When connected to the

SAMMS-MV device, data is displayed on the HHC by a four-

character, seven segment liquid crystal display. When discon-

nected from the SAMMS-MV device, the HHC does not retain

or display data.

Once connected, you can access the functions provided by the

SAMMS-MV device through the use of the HHCs 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.

3.28.1 The (F)unction Key

When you press the (F)unction key, the function mode is

selected and the HHC displays the number of the selected

function preceded by F. With the HHC in the function mode, use

the UP and DOWN keys to step from one function to the next.

3.28.2 The LIST Key

When you press the LIST key, the display mode is selected and

the HHC displays the value corresponding to the selected

function. If the selected function is a set point, the HHC displays

the actual setting. If the selected function is a measured

quantity, the HHC displays the value of the measured quantity.

In the display mode, use the UP and DOWN keys to step

through the range of possible set points for the selected

FLC