220v/460v 3phase generators/motors

guest: 1st question, it is one generator, 2nd question, it depends on how it is bad, can the grounded winding be isolated from the other windings? is it a turn to turn short, or?

a turn to turn could get hot and damage the other good windings. perry

hi perry

they are isolated windings,the marking is like this:

winding#1 ends are 1-4

winding#2 ends are 2-5

winding#3 ends are 3-6

winding#4 ends are 7-10

winding#5 ends are 8-11

winding#6 ends are 9-12

at all times ends# 10,11,12 are connected together, now when i want it on 480v i connect ends 4 to 7, 5 to 8, 6 to 9 and the line leads will be 1,2,3.

if i want it on 240v i connect ends 1 to 7, 2 to 8, 3 to 9, and connect 4,5,6 together with ends#10,11,12 and the line leads will be 1-7 and 2-8 and 3-9.

from this you can see that on 480v windings#1,4 will be on series. and also windings#2,5 and 3,6. but on 240v they will be on parallel.

i can send you drawing so you will get it easier if you give me your e-mail.

thanks for your help

guest: a 12 terminal generator or motor is top of the line, if you can picture the letter Y, or wye, make that with 2 coils in each leg of the Y, and the center of the Y separated you would have 6 coils with 12 terminals. starting with the outer coil at the 2:00 time position, this would T1, the coil at 6:00 position would be T2, the coil at 10:00 position T3, back to the 2:00 position the other end T1 would be T4, T2 would be T5, T3 would be T6, now back to the 2:00 inner circle, that coil would T7, the other end would be T10, and so on for the remaining coils. tie T10,11,12, together and bring out a conductor & call it neutral, measure voltage from neutral to each of the 3 lines & you should read 277 volts A.C., measure voltage between the T's should be 480 volts A.C. with the voltage lowered to 415 volts, the neutral to phase voltage would be 240 volts A.C. you could also connect the coils in a Delta connections, or a dog leg connection. the coils are wound 120 degrees spacing in the stator, this pretty much fills the slots of the stator, this means coils from different phases share slots, if a coils goes bad, (short to another coil, or to ground) it usually causes major damage if you try keeping operating the motor or generator. perry