Elevator Feeders, Breaker, Disconnect

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cyriousn

Senior Member
Location
ME / CT
Occupation
EE & BIM
Hello all. I am dealing with Schindler elevator and I am having a hard time understanding what they are asking for on their overcurrent protection.

Here are the stats on the elevator:
480V-3phase
30 HP Elevator Type Motor (80 starts per hour)
Name plate amperage = 41 amps
Locked Rotor Amps = 123 amps

The cutsheet tells me to use a 60Amp disconnect with 60 amp dual element fuses. Okay that's fine.

It then says to use an inverse time (therm-mag) Breaker that can handle the Locked Rotor Amps which is 123 amps.

So I have two protecting devices, one at 60 Amps, the other at 125. Can I size the feeders for only the 60 amps or do I have to size it for the 125? I am slightly confused as to how this all works. I called Schindler and of course I left a voice message but who knows how long that will take! :grin:
 
Also it says, "On an intermediate basis, 32.5 HP can be developed at full car capacity for 4.5 seconds." From that statement I should be able to size the conductors off of 125% of the amperage based off of Table 430.250 when looking at 30HP motor give or take a few amps. That would be sizing my conductors for 60A. Is it fine to have 60A feeders while having a 125A Breaker?
 
So to add to my last post....
60/60 Disconnect
125A Therm, Mag breaker
60A Feeders (#4's)

....errrrrr :-?
 
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