Eaton MP-3000 Instruction Leaflet page 70

IM02602002E
The MP-3000 declares a motor stop after about 20 cycles of no cur-
rent. The only way to extend this time is to assign the MOTOR STOP
function to one of the discrete inputs, and connect an external stop-
indicating contact. Refer to Subsection 5.6.1 for details.
If the ac supply returns after the stop declaration, but before the
MP-3000 microprocessor shuts down, the MP-3000 relay can go
through another start cycle and return to the RUN state without ever
tripping the motor. However, this on-the-fly restart declaration won't
happen if the relay has antibackspin or other jogging timer blocking in
effect. The relay trips at the moment the MP-3000 declares a stop.
WaRNING
BEWaRE Of RE-ENERGIZING MaNy LaRGER MOTORS afTER
aN INTERRUPTION Of MORE ThaN 20 CyCLES, BUT LESS
ThaN SEVERaL SECONDS. ThE INDUCED ROTOR CURRENT
DECayS SLOWLy, yET ThE ROTOR SLOWS ITS ROTaTION aND
DEVELOPS a LaRGE aNGULaR DIffERENCE fROM ThE DIS-
CONNECTED STaTOR fIELD. WhEN ThE STaTOR IS RE-ENER-
GIZED afTER 30 TO 40 CyCLES, ThE SUDDEN TORQUE ShOCK
CaN BREaK a ShafT KEy, OR DO MORE SERIOUS MEChaNI-
CaL DaMaGE. USE a CONTaCTOR WITh aN aPPROPRIaTE
DROPOUT DELay.
Page 9-6
MP-3000
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