Class 8839 58M Enclosed AC Drives
Application Information
When selecting and applying AC Drives, the following items should be considered where they are applicable. Proper selection and application of an AC Drive is essential to ensure reliable operation and maximum performance of the connected motor load. Please consult Product Data Bulletin SC100 R5/95 “Adjustable Frequency Controllers Application Guide” for further details.
1.AC Drive selection
2.Ambient temperature/altitude
The Class 8839 58M Enclosed AC drives are also rated for up to 3,300 feet (1,000 meters) altitude without derating. Above these ratings, the AC drive must be derated by 1.2% for every 300 feet (100 meters) up to a maximum of 6,600 feet (2,000 meters). For conditions where altitude exceeds 6,600 feet, special considerations apply. Environment, application, loading, and ambient operating conditions could extend altitude range.
AC Line & Motor Voltage
3.AC Line & motor voltage
4.Power factor
5.Harmonics
6.Input currents with and without line reactors
7.Drive isolation transformer
8.Speed range & regulation
9.Accelerating torque
10.Dynamic braking
11.Follower signals
12.PI regulator
13.Bypass operation
14.Motor selection
15.Enclosure types
16.Relay contact ratings
AC Drive Selection
The Class 8839 58M Enclosed AC drive is selected based on the connected motor full load current. AC drives in this catalog are listed by horsepower, voltage and maximum continuous output current ratings that align to the latest NEC ratings. The motor horsepower rating may be used to select the AC drive, provided it’s full load current does not exceed the maximum continuous output current rating of the drive. When the motor full load current does exceed the maximum continuous output rating of the AC drive, a larger one must be selected.
In
Ambient Temperature/Altitude
The AC Drive and connected motor is rated to operate in an ambient temperature of
170
The Class 8839 58M Enclosed AC drives are designed for operation under continuous rated input power from 208 V, 230 V and 460 V line voltages, ± 10% at 50/60 Hz. The selection tables list the horsepowers available at the different voltage ratings. Alternate line voltage configurations are also available on a special order basis. Consult the Drives Applications Group for those applications.
Normally, input voltage and motor voltage will be the same, however, certain applications requiring constant torque above 60 Hz base speed will involve connecting the AC drive to a 460 V supply and connecting the motor for 230 V at 60 Hz. The AC drive can be adjusted to provide 230 V out at 60 Hz and 460 V out at 120 Hz. If this mode of operation is desired, the AC drive must be selected based on the full load current at 230 V.
Power Factor
The Class 8839 58M Enclosed AC drive uses bridge rectifiers which convert the fixed voltage and frequency from the AC line to a fixed DC bus voltage. Operation of the rectifiers does not cause any additional displacement between the voltage and current on the AC line feeding the AC drive.
This means that the displacement power factor (power factor measured by the utility) will not be degraded. Therefore, the AC drive power factor is rated 0.95 or better (lagging) at all times.
Harmonics
Concerning the subject of harmonics, all types of adjustable speed drives using power semiconductors and switching power supplies will produce harmonic currents, which will cause a
©
09/2003
