Rockwell Automation 20G PowerFlex 750-Series AC Drives - Manual (Page 172)

172 Rockwell Automation Publication 750-RM002B-EN-P - September 2013
Chapter 3 Diagnostics and Protection
Table 10 - Other Parameters
Overspeed Limit An overspeed condition results when the motor speed falls outside of its normal
operating range. The forward motor rotation limit is P520 [Max Fwd Speed] +
P524 [Overspeed Limit] and the reverse motor rotation limit is P521 [Max Rev
Speed] - P524 [Overspeed Limit]. In Flux Vector Control mode or Scalar
Control mode with encoder, the motor speed used is a 2msec averaged value of
P131 [Active Vel Fdbk]. In Scalar Control mode without an encoder, the
overspeed check uses P1 [Output Frequency]. The overspeed condition must
exist for at least 16 milliseconds before it causes a fault to occur.
Parameter No. Parameter Name Description
411 Mtr OL at Pwr Up Motor Overload at Power Up parameter configures the motor overload
feature regarding the state of the overload counter at power up.
• “Assume Cold” (0) – P418 [Mtr OL Counts] will be reset to zero the next
time the drive is powered up.
• “UseLastValue” (1) – The value of P418 [Mtr OL Counts] will be
retained at power down and restored the next time the drive is
powered up.
• RealTimeClk (2) – The value of P418 [Mtr OL Counts] begins to
decrease at drive power down, reflecting the cooling of the motor, and
stops at drive power-up or when zero is reached. This option is only
available when the real time clock is active on the drive.
412 Mtr OL Alarm Lvl You can have the drive issue an alarm when the P418 [Mtr OL Counts]
reaches a certain level. Enter this value in P412 [Mtr OL Alarm Lvl]. This
alarm level is different than, and independent of, the alarm action
selected by P410 [Motor OL Actn].
413 Mtr OL Factor Motor Overload Factor parameter sets the minimum level of current (in
percent or P26 [Motor NP Amps]) that causes the motor overload counter
to increment. Current levels below this value decrement the overload
counter. For example, a service factor of 1.15 implies continuous operation
up to 115% of nameplate motor current.
414 Mtr OL Hertz Motor Overload Hertz parameter selects the output frequency below
which the motor operating current is derated (more sensitive) to account
for the reduced self-cooling capability of typical motors, operating at
slower speeds. For motors with extra low speed cooling capacity (for
example 10:1 or blower cooled), reduce this setting to take full advantage
of the motor being used.
415 Mtr OL Reset Lvl Motor Overload Reset Level parameter sets the level that resets a motor
overload condition, and lets a fault (if selected as the motor overload
action) be manually reset.
416 MtrOL Reset Time Motor Overload Reset Time parameter displays the time it takes to restart
the drive after a motor overload fault has occurred and the value in P418
[Mtr OL Counts] is less than the P415 [Mtr OL Reset Lvl].
418 Mtr OL Counts Motor Overload Counts parameter displays the accumulated percentage of
motor overload. Continuously operating the motor over 100% of the
motor overload setting increases this value to 100% and cause the action
selected in P410 [Motor OL Actn] to be taken.
419 Mtr OL Trip Time Motor Overload Trip Time parameter displays the inverse of the motor
overload time, equal to the number of seconds before P418 [Mtr OL
Counts] reaches 100%, and the motor overload action is taken.