■ The frequency converter must be suitable for the operation of a working machine with constant
torque. Models with squared torque may not be used.
■ Drive motor rated power ≤ 75 hp:
To avoid bearing damage at the drive motor, install components for magnetic shielding at the
frequency converter's phase wire output ends (e.g., rings with high permeability).
■ When operating the machine with frequency converter, the drive motor must be designed as
follows:
─ Voltage < 500 V ≥ 100 hp:
Standard winding and isolated bearing or bearing shield at the control side, regardless of
the model.
─ Voltage ≥ 500 V < 100 hp:
Enhanced winding isolation, standard bearing, regardless of the model.
─ Voltage ≥ 500 V ≥ 100 hp:
Enhanced winding isolation and isolated bearing or bearing shield at the drive and the con‐
trol side, regardless of the model.
■ Frequency converters providing a lower initial voltage than the rated motor voltage will cause
an increased power consumption and heat development in the drive motor. This results in a
reduced nominal motor power that can be utilized and thus a decrease in the machine's regu‐
lating range. To avoid damage to the drive motor, please consult with the manufacturer of the
frequency converter.
■ Use a frequency converter with IGBT transistors.
■ The speed change should be approx. 5 Hz per second. This value applies also for the starting
ramp from standstill to reaching minimum frequency. Changing the settings, either slower or
faster, may be possible after verification by an authorized KAESER service representative.
■ The frequency converter may be switched onto a motor in standstill only, in order to avoid mal‐
functions.
■ Upon deactivation of the frequency converter, it must be impossible to reactivate it until after
complete machine standstill.
■ For a shut-down in the event of a malfunction, integrate the following devices in the user's con‐
troller:
─ PTC resistor for monitoring the winding temperature of the drive motor.
─ Thermostat for monitoring the blower block discharge temperature.
■ For safety-technical reasons, an automatic restart of the machine is not permitted and must be
fully deactivated when parametrizing the frequency converter.
■ The maximum conductor length between the output of the frequency converter and drive motor
is 98 ft. Longer conductors may be possible upon verification by an authorized KAESER serv‐
ice representative.
■ Only shielded conductors may be used to connect the machine to ensure an EMC compliant
connection and machine operation.
─ Do not twist the braided shield of these conductors. The braided shield must be generously
spread two-sided across the ground potential.
─ Use only EMC shield clamps or EMC-compliant screwed cable glands.
─ This also applies to other connecting cables, such as the thermistor sensors (PTC) of the
drive motor.
Further information Consult with an authorized KAESER service representative to determine an appropriate frequency
converter.
6
Installation
6.5
Connecting the machine to the power supply
42
Installation and Operating Manual Rotary lobe blower
HBPI pr
Number: 9_9572 28 USE
