User manual

78
Version 2.4 (10/2011) en
Original instructions
Drum Motor
Options and accessories
The dependency of torque as shown in the figure above is written as P = T x .
With decreasing operating frequency less than 20/24 Hz, motor torque derating is
provoked by changed heat removal. The power loss transfer is different in nature
from standard ventilated motors affected by the oil volume. The hyperbolic
character of the power equation written above supersedes to quadratic when
driven with frequencies above 80…85 / 95...100 Hz affected by break-down
torque and voltages influences. The output voltage/frequency curve of most of 3
x 400V / 3 x 460V supplied frequency converters can be set to 230 V / 50 Hz to
connect 230 V motors. This practice generates additional motor power loss which
increases abnormal heating up.
Frequency converter
parameters
• Clock frequency: A high clock frequency leads to a better capacity factor of
the motor. Optimal frequencies are 8 or 16 kHz. Parameters such as cycling
testing quality (round run of the motor) and noise creation also profit from high
frequencies.
• Voltage increase: Interroll motor-windings are designed for a nominal
voltage increase speed of 1 kV/s. If a frequency converter produces a
steeper voltage increase, motor throttles can be installed between the
frequency converter and motor. However, since all Interroll drum motors run in
an oil bath, there is very little danger of overheating or damaging the motor
due to steep voltage increase. If in doubt, please refer to your local Interroll
distributor.
• Voltage: If a single phase input frequency converter is installed with the drum
motor, ensure that the motor specified is supplied and connected for the used
input voltage!
• Output frequency: Care should be taken with applications using output
frequencies above 87/100 Hz. High frequencies can cause noise, vibration
and resonance and will reduce the nominal torque output of the motor. Care
should also be taken when using converters with frequencies under 25 Hz
where overheating and loss of power to the motor could occur. If in doubt,
please refer to your local Interroll distributor.
• Motor performance: Not all frequency converters are able to control motors
with more than 6 poles and/or output powers under 0.2 KW / 0.25 HP. If in
doubt, please refer to your local Interroll distributor or frequency converter
supplier.
• Frequency converter parameters: Frequency converters are usually
delivered with a set of standard parameters. This allows the frequency
converter to be ready for use immediately. However, these standard
parameters may not be specifically optimized for your motor and therefore, it
may be necessary to adjust the parameters for a specific motor.