Chapter 5—System Configuration and Operation96 Power Xpert C445 Global Motor Management Relay MN042003EN—October 2016 www.eaton.comAuto Transformer Operation ModeThe auto transformer reduced voltage motor starter profileaccepts start/stop commands to control motors wired in areduced voltage auto transformer configuration. When a startcommand is received Output 3(star) will be activated. Thenafter the Network Contactor Delay time expires, Output1(start) activates starting the motor with the reduced voltagefrom the auto transformer. When the C445 detects themotor is up to speed or the Maximum Star Winding Timeexpires, whichever occurs first, the Network Contactor Delaytimer is started and Output 3 is de-activated. After theNetwork Contactor Delay time expires, Output 2(run) alsoactivates, which transitions the transformer to full voltage.After a second Network Contactor Delay time expires,Output 1(start) de-activates placing the control into fullvoltage run mode.The C445 will issue a control fault when:● A Run1 command is active and phase voltage is presentand no phase current is detected after the ControlSwitching Time expires.● A Stop command is active and current is detected after theControl Switching Time expires.Outputs 1, 2 and 3 will be de-activated anytime the C445experiences a fault/inhibit condition.● Output 1 – auto transformer reduced voltage starterSTART coil (NO)● Output 2 – auto transformer reduced voltage starter RUNcoil (NO)● Output 3 – auto transformer reduced voltage starter STARcoil (NO)Figure 114. Timing Diagram for the Auto TransformerOperation ModeRecommended User Interface Options for theAuto Transformer Operation ModeFigure 115. C445UM: Monitoring User InterfaceThe Monitoring User Interface can be used with anyoperation mode. If selected as a local control source, theUser Interface Start and Stop buttons are enabled in AutoTransformer Mode. Users may optionally disable local startor reset functionality if desired.C445UM may still be used in Auto Transformer if the UserInterface is not the local control source. Start, Stop and Autobuttons will be disabled. If pressed, the screen will notify theuser that this functionality is not enabled. Control StatusLEDs indicating running, stopped and Auto status will stillfunction.Figure 116. C445UC-I0: IEC Control and StatusFigure 117. C445UC-I1: IEC Status OnlySTARSTARTTiming DiagramRUNSettle TimeMax star timeSettle TimeControl Fault DelayControl Fault Delay
