sequential start motor starting

[stanbyyourword]

ive been wondering about a motor circuit that i havent seen in quite awhile, the sequential-start circuit, where A) one 3 phase motor has 6 leads, B)one 3 pole contactor is energized to first 3 poles and in turn off load side of first contactor to coil of second 3 pole contactor powering second pair of 3 leads at motor, both staying in , now i understand its a form of soft start, what i cant remember is its configuration on windings, ie 6 seperate windings? star delta etc? which i doubt as there is no dropout contactor, looked for drawings couldnt find, a short summary would be great if anyone can , forgot to say was very common w carrier/carlyle kit from 1980s 10 to 20 ton range , thanks regards stan

[maxster]

that is a Part Winding Start set-up,most common on 208/230 volt 3 phase loads and is basically 2 seperate windings within.the compressor/motor 1-2-3 START then 4-5-6 RUN with a timed delay between the closures and when you read the amperage during the run you "double it" or read the 3 lines in to the unit for the rla.when you ohm them out you should have a short on 1,2,3 and a open reading to the casing.then a short on 4,5,6 and open again to the casing, but never and reading...OPEN between those 2 windings 1-4,2-5,3-6 or any other mix of strat to run wire numbers.on Trane...Carrier and Yorks but....McQuay has a wierd configuration when ringing out their semi-hermetics