Ac input power sizing requirements – Rockwell Automation 1398-DDM-xxx ULTRA 100 Series Drives Installation Manual User Manual

Page 112

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Publication 1398-5.2 – PDF 1997

7-8

Power Connections

Table 7.4:

AC Input Power Sizing Requirements

Drive Model

Input Current

Inrush

Current

Fuse

Size

1

Wire Size

mm (AWG)

Transformer Size

a

1398-DDM-005 or

1398-DDM-005X

5 A AC

rms

75 A peak

5 A

1.5 (16)

1 kVA min

100 kVA

max

1398-DDM-009 or

1398-DDM-009X

9 A AC

rms

100 A peak

10 A

2.5 (14)

2 kVA min

100 kVA

max

1398-DDM-019 or

1398-DDM-019X

18 A AC

rms

100 A peak

20 A

4.0 (12)

4 kVA min

100 kVA

max

1. In the United States, the National Electrical Code (NEC), specifies that fuses must be selected
based on the motor full load amperage (FLA), which is not to be confused with the drive input cur-
rent. The largest fuse allowed under any circumstances is four times the motor FLA. Therefore the
largest fuse permissible for use with the ULTRA 100 Series is four times the motor rated continu-
ous current (converted to an RMS value). The Digital Servo Drive has been evaluated and listed
by Underwriters Laboratories Inc. with fuses sized as four times the continuous output current of
the drives (FLA), according to UL 508C.

In almost all cases fuses selected to match the drive input current rating will meet the NEC
requirements and provide the full drive capabilities. Dual element, time delay (slow acting) fuses
should be used to avoid nuisance trips during the inrush current of power initialization. The fuse
sizes listed are recommended values, but local regulations must be determined and adhered to.

The ULTRA 100 Series utilizes solid state motor short circuit protection rated as follows:

Short Circuit Current Rating with No Fuse Restrictions:

Suitable for use on a circuit capable of delivering not more than 5000 RMS symmetrical Amperes,
240 Volts maximum.

Short Circuit Current Rating with Fuse Restrictions:

Suitable for use on a circuit capable of delivering not more than 200,000 RMS symmetrical
Amperes, 240 Volts maximum, when protected by high interrupting capacity, current limiting fuses
(Class CC, G, J, L, R, T).

a. Technical Note Number 1 details Transformer Sizing requirements for a variety of applications.

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