MIL-HDBK-1003/3
APPENDIX D (Continued)
manufacturer. Higher current ratings can be obtained by
oversizing the VFD. This rating is very important when sizing
the VFD for the currents needed by the motor for breakaway
torque.
c) Line voltage. As with any motor controller, an
operating voltage must be specified. VFD's are designed to
operate at some nominal voltage such as 240 volts AC or 480 volts
AC, with an allowable voltage variation of plus or minus 10
percent. Most motor starters will operate beyond this 10 percent
variation, but VFD's will not and will go into a protective trip.
A recorded voltage reading of line power deviations is highly
recommended for each application.
d) Additional considerations. The following
information is helpful when applying drives and should be
included and verified prior to selection of a drive:
(1)
Starting torque currents
(2)
Running torque currents
(3)
Peak loading currents
(4)
Duty cycle
(5)
Load type
(6)
Speed precision required
(7)
Performance (response)
(8)
Line voltages (deviations)
(9)
Altitude
(10)
Ambient temperature
(11)
Environment
(12)
Motoring/regenerating load
(13)
Stopping requirements
(14)
Motor nameplate data
(15)
Input signals required
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