ABB PSTX Series Installation And Commissioning Manual page 85

7.9 Slow speed
Slow speed is an individual function, or a pre-start
function to run the motor with low voltage output. You
can use this feature for example to position a traverse or
mill band.
Operate this function through the HMI, I/O or Fieldbus.
Slow speed has 3 pre-specified speeds:
• Fast jog
• Jog
• Creep
The motor strength can be adjusted with separate
parameters. Select a suitable value for the application.
WARNING
The torque when using Slow speed is maximum
of the full motor torque. This is achieved when
using Fast jog and the strength parameter set to
100%.Too high value of the motor strength could
cause oscillations and if set to too low value, the
motor may not start.
WARNING
Because Slow speed function warms up the
motor we recommend to use a PTC or PT100
element for temperature monitoring.
In some conditions, the built-in EOL is not
accurate for this feature.
You can run the motor in the forward and reverse
direction, with different slow speed speeds in each
direction. When the Softstarter receives a Slow speed
signal, the motor accelerates up to a constant speed
that is slower than the nominal speed, for as long as the
slow speed signal remains active. When the Slow speed
signal is deactivated, the Softstarter immediately cuts the
voltage applied to the motor and the motor stops. For
navigation, see 6.2.4 Motor jog.
Slow speed is configured with the following
parameters:
Parameter
02.07 Pre-start function
02.08 Pre-start time
05.01 Slow speed forward
05.02 Slow speed forward strength
05.03 Slow speed reverse
05.04 Slow speed rev strength
Description
Set to Slow speed forward or Slow speed
reverse.
Sets the duration of the pre-start function.
Sets the Slow speed forward. Fast jog forward
is 33%, Jog forward is 15% and Creep forward
is 8% of the nominal motor speed.
Parameter related to the torque that is
generated during Slow speed in the forward
direction.
Sets the Slow speed reverse. Fast jog reverse is
33%, Jog reverse is 20% and Creep reverse is
9% of the nominal motor speed.
Parameter related to the torque that is
generated during Slow speed in the reverse
direction.
1SFC132081M0201
INFORMATION
Do not use slow speed for more than 2
minutes, as this will cause the motor to heat up
excessively.
INFORMATION
Slow speed is only working when the Softstarter
is connected in-line.
Setting range
Off, Motor heating,
Stand-still brake, Jog
forward, Jog backward
0.0 ... 7200.0 s
Fast jog, Jog, Creep
10 ... 100%
Fast jog, Jog, Creep
10 ... 100%
| Installation and commissioning manual | Functions
7
Default value
Off
10.0 s
Jog
50%
Jog
50%
85