Transformer selection, Circuit breaker/fuse selection – Rockwell Automation 2198-Hxxx Kinetix 5500 Servo Drives User Manual User Manual

Page 31

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Rockwell Automation Publication 2198-UM001D-EN-P - May 2014

31

Planning the Kinetix 5500 Drive System Installation

Chapter 2

Transformer Selection

The servo drive does not require an isolation transformer for three-phase input
power. However, a transformer can be required to match the voltage
requirements of the drive to the available service.

To size a transformer for the main AC power inputs, refer to the Kinetix 5500
power specifications in the Kinetix Servo Drives Technical Data, publication

GMC-TD003

.

Circuit Breaker/Fuse Selection

The Kinetix 5500 drives use internal solid-state motor short-circuit protection
and, when protected by suitable branch circuit protection, are rated for use on a
circuit capable of delivering up to 200,000 A.

While circuit breakers offer some convenience, there are limitations for their use.
Circuit breakers do not handle high current inrush as well as fuses.

Make sure the selected components are properly coordinated and meet
acceptable codes including any requirements for branch circuit protection.
Evaluation of the short-circuit available current is critical and must be kept below
the short-circuit current rating of the circuit breaker.

Refer to

Power Wiring Examples

, on

page 190

, for the wiring diagram.

IMPORTANT

When using an autotransformer, make sure that the phase to neutral/ground
voltage does not exceed the input voltage ratings of the drive.

IMPORTANT

Use a form factor of 1.5 for three-phase power (where form factor is used to
compensate for transformer, drive module, and motor losses, and to account
for utilization in the intermittent operating area of the torque speed curve).

IMPORTANT

150 KVA, max and 3% impedance, min

EXAMPLE

Sizing a transformer to the voltage requirements of this drive:
2198-H040-ERSx = 8.4 kW = 12.6 KVA transformer.

IMPORTANT

UL has not approved circuit breakers for use as branch circuit protection for
Kinetix 5500 drive systems.

ATTENTION: Do not use circuit protection devices on the output of an AC drive
as an isolating disconnect switch or motor overload device. These devices are
designed to operate on sine wave voltage and the drive’s PWM waveform does
not allow it to operate properly. As a result, damage to the device occurs.

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