Rockwell Automation 1902 Syncpro II - Manual (Page 11)

Rockwell Automation Publication 1902-IN001B-EN-E - April 2013 11
Product Description Chapter 1
Typical Synchronous Starter
Components Motor Contactor (M)
The following details outline some of the common components that which the
SyncPro II can be connected to, or are part of the SyncPro II protection package.
The motor contactor is used to provide and switch the power supplied to the
motor stator. It is controlled by the SyncPro II package and is necessary to remove
stator power in the event of a stop command or a trip condition. Two normally
open contactor auxiliaries may be required; one mandatory N.O. contact to give
contactor status information to the SyncPro II, and one may be needed as a hold-
in contact for the main control circuit.
Motor Contactor Pilot Relay (CR1 or MR)
This interposing relay allows the SyncPro II output to pick up the main contactor
coil. The power requirements of the pick-up coils used in most medium voltage
motor starters would exceed the switching capability of the 1764-24BWA output
contact.
Field Voltage Relay (FVR)
When energized, this DC relay indicates that the DC exciter supply is healthy
and producing an adequate level of DC excitation. The field voltage relay is
required to prevent starting the motor unless DC excitation is available. A field
voltage relay is recommended as the SyncPro II does not have the ability to
determine the level of the exciter output voltage. It is needed to prevent
unnecessary starts when synchronization cannot occur.
Equipment Shutdown Relay (ESR) (Included with SyncPro II)
The ESR relay combines the status of customer supplied protective and interlock
devices to a single contact input on the SyncPro II.
When ESR is energized, it is an indication that all external trip and interlock
contacts to the SyncPro II are in a "not tripped" condition. All external trips and
interlocks must be wired in series with the ESR coil in order to be properly
addressed by the SyncPro II.
Phase Angle Transducer (Included with SyncPro II)
The phase angle transducer provides a conditioned 4...20 mA signal to the analog
module of the SyncPro II system. The transducer is factory calibrated to provide a
specific output at zero (0) lagging power factor, at 1.0 or unity power factor, and
at zero (0) leading power factor. These factory settings must not be altered.