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PARAMETER
DESCRIPTIONS
VACON
• 69
This is the maximum amount of time permitted in underload status. An internal timer measures the time accumulated in underload status. If the underload timer exceeds this limit, the protection will cause a fault as in parameter
6.5. If the pump stops, the underload timer resets to zero. See Figure 1-23.
Figure 10.5: Underload Timer Function
MOTOR THERMAL PROTECTION (PARAMETERS 6.9 - 6.11)
Motor thermal protection is to protect the motor from overheating. The Vacon
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 thermally
overheat. This is particularly the case 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.
Motor thermal protection is based on a calibrated model and uses the output
current of the drive to determine the load on the motor.
Motor thermal protection can be adjusted with parameters. The thermal current IT specifies the load current above which the motor will be overloaded.
This current threshold is a function of the output frequency.
!
CAUTION! The calibrated model does not protect the motor if the
air intake grill is blocked and reduces the airflow to the motor.
24-hour support (0)201 212 575 • Email: [email protected]
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