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3.5.1 Frequency converter operation
DANGER
Explosive environment
Death or serious personal injury
- Whenever you use powered equipment in
explosive surroundings, observe the rules and
regulations generally or specifically imposed by
the relevant responsible authorities or trade
organisations.
You can connect all three-phase motors to a frequency converter.
However, frequency converter operation often exposes the motor
insulation system to a heavier load and causes the motor to be
more noisy than usual due to eddy currents caused by voltage
peaks.
If in doubt whether the supplied motor can handle
frequency converter operation contact the motor
supplier,
In addition, large motors driven via a frequency converter will be
loaded by bearing currents.
When the pump is operated via a frequency converter, check the
following operating conditions:
Operating
Action
conditions
2-, 4- and 6-pole
Ensure that the non-drive-end motor
motors, frame size
bearing is electrically isolated.
225 and larger
Fit a dU/dt filter between the motor and
Noise-critical
the frequency converter. It reduces the
applications
voltage peaks and thus the noise.
Particularly
noise-critical
Fit a sinusoidal filter.
applications
Fit a cable that meets the specifications
laid down by the frequency converter
Cable length
supplier. The length of the cable
between the motor and frequency
converter affects the motor load.
Supply voltage up to
Make sure that the motor is suitable for
500 V
frequency converter operation.
• Fit a dU/dt filter. It reduces the voltage
Supply voltage
peaks and thus the noise.
between 500 V and
• Or make sure that the motor has
690 V
reinforced insulation.
• Fit a dU/dt filter.
Supply voltage of 690
• Make sure that the motor has
V and upwards
reinforced insulation.
6
4. Starting up the product
4.1 Priming
CVM and CHM pumps are non-self-priming and must be
completely primed, that is filled with liquid, before starting.
•
If the pump will be operating with a positive inlet pressure,
prime it by opening the inlet valve and allowing liquid to enter
the pump housing. Open the vents and make sure all air is
forced out of the pump by the liquid before closing the vents.
•
Rotate the shaft by hand to free entrapped air from the
impeller passageways.
•
If the pump will be operating with a suction lift, priming must
be accomplished by other methods. Use foot valves or
ejectors, or fill the pump housing and the inlet line manually
with liquid.
Never run the pump dry in the hope that it will prime
itself. The result will be serious damage to the shaft
seals, pump wear rings and shaft sleeves.
4.2 Pre-start checklist
Do not operate the product above the nameplate
conditions. This may damage the product.
Make the following inspections before starting your CVM or CHM
pump:
1. Make sure the inlet and outlet pipes have been cleaned and
flushed to remove dirt and debris.
2. Check the direction of rotation which must be clockwise.
Operating in reverse will destroy the impeller and shaft.
3. Make sure all wiring connections to the motor and starting
device are in accordance with the wiring diagram.
4. If the motor has been in storage for a long time, either before
or after installation, refer to the motor instructions before
starting.
5. Check the voltage, phase and frequency with the motor
nameplate. Turn the impeller by hand to make sure it rotates
freely.
6. Tighten the plugs in the gauge and drain holes. If the pump is
fitted with pressure gauges, keep the gauge cocks closed
when they are not in use.
7. Check the inlet and outlet pipes for leaks, and make sure all
flange bolts are tightened securely.
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