Chapter 5—System Configuration and Operation86 Power Xpert C445 Global Motor Management Relay MN042003EN—October 2016 www.eaton.comTwo Speed Two Winding Operation ModeDescriptionThe two speed motor starter operation mode accepts off/slow/fast commands to control two speed motorapplications. A run slow command will activate Output1(slow). A run fast command will activate Output 2(fast). Astop command de-activates both of the outputs.When transitioning from fast R slow, the C445 willde-activate Output 2(fast) and will delay activating Output1(slow) until the Control Switching Time expires, allowing themotor time to slow down before transitioning to the slowspeed. The Control Switching Time parameter can be foundin the Operation Mode category in the Power Xpert inControlSoftware Tool.The C445 will issue a control fault when:● The RunSlow or RunFast command is active and phasevoltage is present and no phase current is detected.● A Stop command is active and current is detected.Note: Even with the control fault disabled, after de-activatingthe present speed, the C445 will NOT transition to thenew speed until current readings decrease to zero.● Outputs 1 and 2 will be de-activated anytime the C445experiences a fault/inhibit condition.● Output 1 – slow starter coil (NO)● Output 2 – fast starter coil (NO)● Output 3 – open for user configuration and function canbe selected by the user.The AtRef (At Reference) bit in the Motor Control Statusregister is set based on the following two conditions. AtReference signals that the motor is up to speed.1. If motor current first exceeds 115% of the activeoverload FLA rating and then decreases back below115% of the active overload FLA rating, it is determinedthe motor has come up to speed and the AtRef bit willbe set.2. If motor current exceeds 30% of the active overload FLArating and remains until after the Motor State Transitionto Run Delay from Start time expires the motor isdetermined to be up to speed and the AtRef bit will beset. This time delay parameter can be found in theGeneral Protections category in the Power XpertinControl Software Tool.Figure 96. Timing Diagram for the Two Speed OperationModeSLOWFASTSpeed Transition DelayTiming DiagramCheck for motor current = 0Control Fault Delay
