Emerson Unidrive M700 Installation Manual page 83

5.1.5 Supply requirements
AC supply voltage:
200 V drive: 200 V to 240 V ±10 %
400 V drive: 380 V to 480 V ±10 %
Number of phases: 3
Maximum supply imbalance: 2 % negative phase sequence (equivalent to 3 % voltage imbalance
between phases).
Frequency range: 45 to 66 Hz
For UL compliance only, the maximum supply symmetrical fault current must be limited to 100 kA
5.1.6 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:
03200050, 03200066, 03200080, 03200106,
03400025, 03400031, 03400045, 03400062
Model sizes 03400078 to 04400172 have an internal DC choke so they do not require AC line
reactors except for cases of excessive phase unbalance or extreme supply conditions.
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
Unidrive M/HS Frame 3 and 4 Power Installation Guide
Issue Number: 3
83