Rockwell Automation 8510 AC Spindle Drive System User Manual - Manual (Page 82)

Wiring
Chapter 8
8-78
Power Transformers
The allowable AC input voltage range is 200 to 230V AC,
±
10% at 60 Hz
and 200 to 220V AC,
±
10% at 50 Hz. In larger plants with high capacity
power systems, it is not uncommon to encounter exceptionally high AC
line voltage that will exceed the +10% specification during part of the day.
In these cases the nominal secondary voltage of the transformer should be
set for 5-10% less than the maximum allowable nominal input voltage of
the drive. This will help avoid drive damage caused by the high AC line
voltage. Transformers supplied by Allen-Bradley are wound with 220V AC
secondaries.
Either autotransformers or isolation transformers can be used. When using
isolation transformers, a “Y” secondary with the neutral grounded is
recommended.
Power transformer kVA requirements depend on the power rating of the
motor being used. Table 8.C defines the transformer requirements.
Table 8.C
Transformer Requirements
Motor Rating
(Cont. / 30 Min. kW)
2.2 / 3.7
3.7 / 5.5
5.5 / 7.5
7.5 / 11
11 / 15
15 / 18.5
18.5 / 22
22 / 30
Transformer Rating
(kVA)
6
9
12
17
22
26
32
40
Power Grounding
The wire size used for power grounds must be at least as large as the wire
gauge of the power conductors or as defined by local codes.
Other Devices and Noise Suppression
Inductive devices (e.g. solenoids, motor starters and relays) must be
equipped with suppression devices that will not allow a dv/dt of greater
than 200 V
/µ
sec. Devices that produce a strong magnetic field (e.g. chokes,
transformers and reactors) must not be mounted closer than 254 mm (10
in.) to the drive. The associated wiring to any of these devices must be
physically separated from any low level signal wiring to minimize induced
voltages.