Eaton QD5 Manual
Also see for COOPER POWER SERIES: Installation and operation instructionsInstallation instructionsInstallation instructionsInstallation and operation instructionsOperation instructions
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Main reversing movable contactsThe reversing switch changes the polarity of the tappedwinding. When the QD5 Quik-Drive tap-changer is in neutralposition, the reversing switch is located on the “VN”Reversing Neutral Stationary Contact. In the open positionthe reversing switch is not in the load current circuit.The reversing switch motion on the QD5 tap-changer occursas the main movable contacts enter or leave the neutralposition. The QD5 tap-changer reversing switch movablecontacts interact with the three reversing stationarycontacts during the buck and boost operation of the tapchanger.The first tap step in either direction rotates the ReversingSegment actuator causing the Reversing Segment Actuatorarms to rotate the reversing switch and engage theappropriate reversing stationary contact. When the tap-changer receives a signal for raise and the reversing switchcontact is in neutral, the reversing movable contacts willmove clockwise on to the VR stationary bridging the VR andVN stationary contacts. In the lower direction from neutralthe reversing movable will move counter clockwise on tothe VL stationary contact. The reversing movable will bebridging the VL and VN when moving in the lower direction.Micro switchesMicro switches are use for the holding switch, reversinglogic, neutral indication and taping limit logic switches.Two sets of normally closed switches are use to provide asafety switch circuit to prevent the tap-changer from tappingbeyond 16R and 16L acting as a fail-safe to the mechanicalstop. The switches enable the tap changer to step back fromthe mechanical stop when the holding switch is closed.The micro switches used are rated for –40°C to 130°C,5 Amp 125/250 Vac rating. The switches are designed toexceed one million operations at QD5 tap-changer current.QD5 tap-changer operating sequenceWhen the tap-changer is in the neutral position and thecontrol calls for a tap change, the following events occur:1. Motor will start and drive the chain sprocket.2. Rotation of the chain sprocket rotates the drive pinion.3. The drive pinion cam engages and closes in the holdingswitch.4. Drive pinion roller engages the position indicator drivegear advancing the position indicator pointer.5. The sprocket drive roller engages the Geneva gearrotating the Geneva gear.6. As the sprocket rotates and the holding switch isactuated, the sprocket cam dis-engages and releasesthe brake.7. The rotation of the Geneva gear causes the reversingsegment actuator to operate which moves thereversing switch movable contacts, via the linkage tyingthe reversing segment actuator to the reversing switchfrom neutral to VR or VL.8. Rotation of the Geneva gear relocates the movablecontacts on the stationary contacts.9. Drive pinion cam returns to the open area opening theholding switch.10. Tap Change is completed.Figure 9. Reversing movable contact assembly.4QD5 QUIK-DRIVE TAP-CHANGER INSTALLATION AND MAINTENANCE INSTRUCTIONS MN225012EN March 2016 |
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