Rockwell Automation 20D PowerFlex 700S with Phase I Control Reference Manual - Manual (Page 48)

48 Rockwell Automation Publication PFLEX-RM002D-EN-E - August 2013
Chapter 1 Detail Drive Configuration and Operation
button on the HIM is one possible source for the [Applied Logic Command]
direction bits. The following chart explains the effect that the direction button
on the HIM has based on the condition of the “Bipolar SRef ” bit:
In either Bipolar or Unipolar mode, the selected direction can be determined
from the sign of Par 41 [Limited Spd Ref ]. Positive values indicate forward
rotation and negative values indicate reverse rotation.
Drive Overload Theory of Operation
The following discussion assumes that the IT curve does not change with Pulse
Width Modulated (PWM) carrier frequency or drive output frequency.
A drive has three rated current values; a continuous current rating, a 1 minute
current rating, and a 3 second current rating. Typically, the 1 minute rating will
be close to 110% of the continuous rating, and the 3 second rating will be close to
150% of the continuous rating. This may vary from drive to drive to optimize the
performance of each frame size. In the following examples the 1 minute rating is
110% and the 3 second rating is 150%.
Open Loop Current Limit
The drive can thermally allow 102.5%.
The 1 minute current rating assumes a duty cycle of 1 minute on, followed by 3
minutes at 100%. This results in an average current of 102.5%.
Bipolar Reference Controlled By HIM? HIM Direction Button
Enabled Yes Changes the motor direction due to a HIM supplied (+) or (-)
command signal.
Enabled No Has no effect on motor direction. Direction determined by sign
of Par 40 [Selected SpdRef].
Disabled Yes Changes the motor direction due to a HIM supplied forward or
reverse [Applied LogicCmd] bit.
Disabled No Changes the motor direction due to a HIM supplied forward or
reverse [Applied LogicCmd] bit.
0
153 00
Max
X
1
1
152
Control Options
(Unipol Fwd) +1
(Unipol Rev) -1
20 152 21
1
0
40
Selected Spd Ref
Applied Logic Cmd
110% * 60 s + 100%*180 s
240 s
average current = ------------------------------------------- = 102.5%