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SPX advanced – description of parameters
SPX ADVANCED APPLICATION MANUAL
SVCH0203—October 2017 www.eaton.com
5.13.4 Speed Error
The Speed error monitoring function compares the encoder
frequency and the ramp generator output. The function
is used with a PMS motor to detect if the motor is off
synchronization or to disable the open loop function using
the encoder speed for slip compensation.
Code
ID
Description
Notes
P1.12.4.1
709
Speed error fault function “Speed error mode”
Defines the fault function when the speed reference and the encoder speed are above
the set limits
0 = No response
1 = Warning
2 = Fault, stop mode after fault always by coasting
P1.12.4.2
753
Speed error maximum difference “Speed error limit”
Defines the limit when fault situation is noted. The difference between the speed
reference and the encoder speed. Percentage value is in relation to motor nominal
frequency.
+ 5 %
- 5 %
P1.12.4.3
754
Speed error delay “Speed Fault Delay”
Defines the delay after which a speed error is considered as a fault.
When used to disable open loop slip compensation based on encoder frequency it is
recommended to set this time to zero to avoid a speed jump at the time of encoder
malfunction.
The slip compensation is disabled regardless of the
response and needs to be re-activated once a speed error is
detected (set parameter again or power down the drive).
5.13.5 Motor Protection
The Speed error monitoring function compares the encoder
frequency and the ramp generator output. The function
is used with a PMS motor to detect if the motor is off
synchronization or to disable the open loop function using
the encoder speed for slip compensation.
CAUTION
The motor thermal protection is to protect the motor from
overheating. The drive is capable of supplying higher than
nominal current to the motor. If the load requires this high
current there is a risk that the motor will be thermally
overloaded. This is the case especially at low frequencies.
At low frequencies the cooling effect of the motor is
reduced as well as its capacity. If the motor is equipped
with an external fan the load reduction at low speeds is
small.
The motor thermal protection is based on a calculated
model and it uses the output current of the drive to
determine the load on the motor.
The motor thermal protection can be adjusted with
parameters. The thermal current IT specifies the load
current above which the motor is overloaded. This current
limit is a function of the output frequency.
The calculated model does not prote ct the motor if the
airflow to the motor is reduced by blocked air intake grill.