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Powerdrive F300 User Guide 77
Issue Number: 2
4.2.1 Supply types
All drives are suitable for use on any supply type i.e TN-S, TN-C-S, TT and IT.
• Supplies with voltage up to 600 V may have grounding at any potential, i.e. neutral, centre or corner (“grounded delta”)
• Supplies with voltage above 600 V may not have corner grounding
Drives are suitable for use on supplies of installation category III and lower, according to IEC60664-1. This means they may be connected
permanently to the supply at its origin in a building, but for outdoor installation additional over-voltage suppression (transient voltage surge
suppression) must be provided to reduce category IV to category III.
A ground fault in the supply has no effect in any case. If the motor must continue to run with a ground fault in its own circuit then an input isolating
transformer must be provided and if an EMC filter is required it must be located in the primary circuit.
Unusual hazards can occur on ungrounded supplies with more than one source, for example on ships. Contact the supplier of the drive for more
information.
4.2.2 Supplies requiring line reactors
Input line reactors reduce the risk of damage to the drive resulting from poor phase balance or severe disturbances on the supply network.
Where line reactors are to be used, reactance values of approximately 2 % are recommended. Higher values may be used if necessary, but may
result in a loss of drive output (reduced torque at high speed) because of the voltage drop.
For all drive ratings, 2 % line reactors permit drives to be used with a supply unbalance of up to 3.5 % negative phase sequence (equivalent to 5%
voltage imbalance between phases).
Severe disturbances may be caused by the following factors, for example:
• Power factor correction equipment connected close to the drive.
• Large DC drives having no or inadequate line reactors connected to the supply.
• Across the line (DOL) started motor(s) connected to the supply such that when any of these motors are started, the voltage dip exceeds 20 %.
Such disturbances may cause excessive peak currents to flow in the input power circuit of the drive. This may cause nuisance tripping, or in extreme
cases, failure of the drive.
Drives of low power rating may also be susceptible to disturbance when connected to supplies with a high rated capacity.
Line reactors are particularly recommended for use with the following drive models when one of the above factors exists, or when the supply capacity
exceeds 175 kVA:
03200066, 03200080, 03200110, 03200127,
03400034, 03400045, 03400062, 03400077
Model sizes 03400104 to 07600730 have an internal DC choke and model sizes 08201490 to 0801080 and frame 9A have internal AC line chokes so
they do not require AC line reactors except for cases of excessive phase unbalance or extreme supply conditions. Drive sizes 9E,10E and 11E do not
have internal input line reactors hence an external input line reactor must be used. For more information refer to section 4.2.3 Input line reactor
specification for size 9E, 10E and 11E on page 78.
When required, each drive must have its own reactor(s). Three individual reactors or a single three-phase reactor should be used.
Reactor current ratings
The current rating of the line reactors should be as follows:
Continuous current rating:
Not less than the continuous input current rating of the drive
Repetitive peak current rating:
Not less than twice the continuous input current rating of the drive
Operation with IT (ungrounded) supplies:
Special attention is required when using internal or external EMC filters with ungrounded supplies, because in the event of a ground
(earth) fault in the motor circuit the drive may not trip and the filter could be over-stressed. In this case, either the filter must not be used
(removed) or additional independent motor ground fault protection must be provided.
For instructions on removal, refer to section 4.10.2 Internal EMC filter on page 90. For details of ground fault protection contact the
supplier of the drive.
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