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Unidrive M Regen Design Guide 117
Issue Number: 4
6.2 Supply requirements
Voltage:
200 V drive: 200 V to 240 V ±10%
400 V drive: 380 V to 480 V ±10%
575 V drive: 500 V to 575 V ±10%
690 V drive: 500 V to 690 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
The maximum supply symmetrical fault current must be limited to 100 kA (also required for UL compliance).
6.2.1 Supply types
Drives rated for supply voltages up to 690 V are suitable for use with supply types with neutral or centre grounding i.e. TN-S, TN-C-S, TT.
The following supplies are not permitted with Unidrive M Regen
1. Corner grounded supplies (grounded Delta).
2. Ungrounded supplies (IT) > 575 V.
6.2.2 Other supplies
Wherever other equipment shares the same low voltage supply, i.e. 400 Vac, careful consideration must be given to the likely need for both switching
frequency and EMC filters, as explained in section 6.5.10 Switching frequency emission and section 6.5.11 Conducted and radiated RF emission on
page 132.
6.2.3 Supply voltage notching
Because of the use of input inductors and an active rectifier the drive causes no notching - but see section 6.5.10 Switching frequency emission on
page 131 for advice on switching frequency emission.
6.2.4 Supply harmonics
When operated from a balanced sinusoidal three-phase supply, the regenerative Unidrive M generates minimal harmonic current.
Imbalance between phase voltages will cause the drive to generate some harmonic current. Existing voltage harmonics on the power system will
cause some harmonic current to flow from the supply into the drive.
This latter effect is not an emission, but it may be difficult to distinguish between incoming and outgoing harmonic current in a site measurement
unless accurate phase angle data is available for the harmonics. No general rule can be given for these effects, but the generated harmonic current
levels will always be small compared with those caused by a conventional drive with rectifier input.
6.3 Cable and fuse ratings
The input current is affected by the supply voltage and impedance.
Typical input current
The values of typical input current are given to aid calculations for power flow and power loss.
The values of typical input current are stated for a balanced supply.
Maximum continuous input current
The values of maximum continuous input current are given to aid the selection of cables and fuses. These values are stated for the worst case
condition with the unusual combination of stiff supply with bad balance. The value stated for the maximum continuous input current would only be
seen in one of the input phases. The current in the other two phases would be significantly lower.
The values of maximum input current are stated for a supply with a 2 % negative phase-sequence imbalance and rated at the maximum supply fault
current given in Table 6-2 to Table 6-5.
The nominal cable sizes given in this section are only a guide. Refer to local wiring regulations for the correct size of cables. In some cases a larger
cable is required to avoid excessive voltage drop.
The nominal output cable sizes in this section assume that the motor maximum current matches that of the drive. Where a motor of reduced rating is
used the cable rating may be chosen to match that of the motor. To ensure that the motor and cable are protected against over-load, the drive must
be programmed with the correct motor rated current.
Fuse protection is required in the following Regen systems:
1. Single Regen, multiple motoring drives
2. Multiple Regen, multiple motoring drives
3. Unidrive M Regen brake resistor replacement
4. Regen systems using a Unidrive M rectifier
If the harmonic distortion of the supply is high for extended periods then this can cause a reduction of the service life of the switching
frequency filter capacitors. The effect of this is to reduce the capacitance value. If high levels of harmonic distortion are expected then it is
recommended that the capacitance values be checked periodically, and capacitors which have fallen outside of their tolerance range be
replaced.
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