Chapter 6 - Parameter Description [DRV]
6-3
This parameter activates the ETH function when set to
‘Yes’. ETH level is set as the percentage of DRV-05
[Motor rated current].
This is the one-minute current level that is used to
determine the motor I
2
t overload curve. For example, if
DRV-07 is set to 130%, the drive would trip in one
minute if 130% of rated motor current in DRV-05
flows for one minute.
ETH Calculation:
Note:
When
1
*]08[*]05[
rSpeedFactoDRVDRV
ntMotorCurre
The ETH will not charge and the drive will run continuously at
that current and speed level.
Note: The set value is the percentage of DRV-05
[Rated Motor Current].
[Motor i
2
t Characteristic Curve]
This is the current at which the motor can run
continuously. This is often considered the service
factor of the motor. Generally, this value is set to
‘100%’, which means that the drive will begin
accumulating motor OL once the current is above the
motor rated current set in DRV-05. If this parameter is
set to 115%, the drive will begin accumulating motor
OL at 115% of the current in DRV-05
Note: This value must be set less than DRV-07
[ETH 1min].
Note: The set value is the percentage of DRV-05
[Rated Motor Current].
Since a motor often runs hotter at slower speeds, the
SG drive provides derating of the ETH function for
different types of motors. For proper motor protection
utilizing the ETH parameters, the following type of
motor must be selected:
[Self-cool] is a standard motor that has a cooling fan
connected directly to the shaft of the motor. The fan
will provide less cooling at lower speeds, causing the
motor to run hotter. The drive will derate the motor
OL calculations to protect the motor at lower speeds. It
accomplishes this function by adjusting the speed
factor, which is shown in the ETH calculations.
The speed factor for operation at and above 60Hz is
1.00.
The speed factor for operation between 20Hz and 60Hz
is:
Speed_Factor =( 0.125 %/Hz * drive frequency (Hz) + 92.5%) / 100%
DRV
►
ETH select
06 --- Yes ---
Factory Default: Yes
DRV
►
ETH 1min
07 130 %
Factory Default: 130 %
DRV
►
ETH cont
08 100 %
Factory Default: 100 %
DRV
►
Motor type
09 Self-cool
Factory Default: Self-cool
Load Current
Trip Time
[ETH 1 min]
1 minute
[ETH cont]
1
*]05[
1
%100
]07[
*.sec60
2
2
rSpeedFactoDRV
ntMotorCurre
DRV
TimetoTrip
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