Emerson Commander SX Advanced User's Manual page 51

CONTROL TECHNIQUES
4.15
: Thermal time constant
Adjustment range : 0 to 250 s
Factory setting : 89 s
This parameter is used to define the motor thermal protection.
If known, the thermal time constant of the motor should be
entered directly in 4.15. Otherwise it should be calculated as
a function of the maximum time for which the motor can
tolerate 150% I .
N
Maximum duration at 150 % I Maximum duration at 150 % I
4.15 =
0.674 0.674
Note: When 7.11 = 8 (ADI2 configured as a PTC input), it is
possible to deactivate the motor thermal protection (itAC
motor overload trip) by setting 4.15 = 0.
4.16
: Thermal protection mode
Adjustment range : 0 or 1
Factory setting : 0
0 (Trip) (deF): The drive will trip when the threshold
defined in parameter 4.15 is reached.
1 (Curr. limit) (Auto): The limiting current will automatically
be reduced below 100% I
N
parameter 4.15 is reached.
4.17
: Reactive current
Adjustment range : ± 9999
Reactive current reading.
4.18
: Overriding current limit
Adjustment range : 0 to +300% (% max. active In)
Depending on the system operation, indicates the rms current
limit in real time.
4.19
: Overload accumulator
Adjustment range : 0 to 100.0%
The accumulator increases according to the formula
4.01
2 -t/4.15
(1-e )
4.19 =
x 100 %
2
(5.07 x 1,05)
When 4.19 reaches 100%, the drive goes into "It Ac" trip
state or causes the limiting current to be reduced.
4.20
: Percentage load
Adjustment range : ± active current limit (% active In)
This parameter indicates the drive load level. A positive value
indicates operation in motor mode whereas a negative value
indicates operation in generator mode (driving load).
ADVANCED USER GUIDE
Commander SX
IP66/Nema 4X variable speed drive
MENU 4: CURRENT AND TORQUE CONTROL
N N
when the threshold defined in
4.21
: Selection of load display
Adjustment range : 0 or 1
Factory setting : 0
This parameter is used to obtain an indication of the load or
the total current on the display.
LCD LED
4.21
display display
0 As % Inom Ld
1 In Amps A
4.22 4.51
to : Not used
4.52
: Max. speed in torque control mode
Adjustment range : 0 to 32000 rpm
Factory setting : 1500 rpm
In torque control mode, this parameter is used to set the
speed at which the drive reverts to speed regulation, in order
to avoid reaching an excessive rotation speed. The
maximum speed taken into account corresponds to the
value of parameter 4.52 + 20%.
Note: Parameter 1.06 Maximum reference clamp is always
active.
3854 en - 03.2008 / b
Functions
Display of the drive load
level 4.20.
Display of the total motor
51