Troubleshooting - Siemens SINAMICS G120X Commissioning Manual

3 Commissioning using IOP-2
3.3.2

Troubleshooting

Table 3-4
Issue
Nuisance Overcurrent
or Ground Fault during
PolID or stationary ID
test.
[F07807: Short
cct/grnd F]
Motor current
increases significantly
when operating at low
speeds continually
despite no mechanical
issues being present.
Drive faults with the
message PolID
incorrect
Motor stalls or
struggles to run-up
Motor oscillates or
tends to oscillate
Motor overspeed fault
G120X commissioning guide for permanent magnet motors PMSM
Entry-ID: 109780815, V1.0,
Possible reason
Due to the reasons
described in chapter 3.2
Step 5, the value of
rated voltage is too high.
The motor is operated
below the minimum
allowed speed defined
by p1755 Motor model
changeover speed
encoderless operation.
Motor has significant
pole saliency
Pole position
identification current is
too high
Not enough starting
torque generated by
drive
Motor magnetic circuit
oversaturated
Transition between open
loop to closed loop
phase during
acceleration is not
stable
Closed loop controller
gains inappropriate
Speed overshoot at the
end of fast acceleration
07/2020
Remedy
First check the motor wiring and
insulation resistance to confirm nuisance
tripping. Calculate the new motor rated
voltage using one of formulas in chapter
3.2 Step 5. Provided it's lower than the
original one use the new value (in
Advanced Startup menu) and re-run
stationary motor ID test (Advanced
Startup →Optimisation →Motor
Identification →MotID only standst).
You can also repeatedly reduce original
value in 5 to 10V steps followed every
time with stationary ID test until the
nuisance trip is not occurring any more.
Note: If you directly change motor rated
voltage in p304 (p10=3), then after each
change re-calculate motor model p340=1
and only then re-run stationary ID test
p1900 = 2.
Ensure the motor is always operated
above the p1755 value and never below
15% of rated speed.
Set the Minimum speed p1080 > p1755.
Change PolID technique p1980 to value 4
or 10.
Reduce value in p329. Do it in about 10%
steps as too low a value leads to
inaccuracy in motor control.
Increase p1610 or/and p1611 value.
Before any attempt to re-run the motor
allow it to cool down.
Check setting p1610 and p1611 and
reduce them by 10% steps gradually to
see the effect.
Gradually increase p1755 in approx. 10%
steps until the transition is smooth and
stable.
Perform speed controller optimization,
chapter 3.3.1.
Increase p1120 Ramp up time or
increase p1131 Final rounding 1. Perform
speed controller optimization, chapter
3.3.1.
16