ohhhhhhkay.
Just spent 7 soddin hours on a new starter (see above).headbangheadbangheadbang
One dinky little problem - I must be getting old, `cos I can`t get my head around this one TEENSY little bit:
The Main contactor pulls in, and latches inself, through the "satisfied" switch. This supplies the timer - 3 wire model, which I`ll come to in a min.
Timer supplies Star contactor, which pulls in for approx 5 seconds, then drops out. However, voltage across timer then collapses, and star contactor pulls back in before the delta contactor does anything.
The timer has 3 wires; lets call them 1, 2 and 3.
wires 1 & 2 provide timer operation; wires 2 and 3 are a time-delayed, N/C switch.
Lets call the coil wires from the star contactor Sa1 and Sa2
And the ones from the delta..... yup. Da1 and Da2
ignoring the un-necessary bits:
L1 to Sa2
L2 to timer1
timer2 to Sa1 and Da1
L3 to timer 3 and Da2
So: at start, we have short circuit between timer2 and timer3, effectively putting L3 and L1 across the star contactor; with L2, and L3 supplying the timer wires 1 and 2 (via the coil of the delta contactor.)
My thinking was that, when the switch opened after the time delay expired:
timer 2 has become O/C from timer 3. Delta coil is now supplied via L3 and timer wire 2, through the timer load and wire1,from L2
BUT.......
The moment the star contactor opens; the delta "begins to move", however for whatever reason (think I`m losing operating voltage on the timer), timer resets, wire2 from the timer shorts to L3 again, and the star contactor closes again, for a new timing cycle.
Somebody tell me what I`ve missed. Please?
KME
Just spent 7 soddin hours on a new starter (see above).headbangheadbangheadbang
One dinky little problem - I must be getting old, `cos I can`t get my head around this one TEENSY little bit:
The Main contactor pulls in, and latches inself, through the "satisfied" switch. This supplies the timer - 3 wire model, which I`ll come to in a min.
Timer supplies Star contactor, which pulls in for approx 5 seconds, then drops out. However, voltage across timer then collapses, and star contactor pulls back in before the delta contactor does anything.
The timer has 3 wires; lets call them 1, 2 and 3.
wires 1 & 2 provide timer operation; wires 2 and 3 are a time-delayed, N/C switch.
Lets call the coil wires from the star contactor Sa1 and Sa2
And the ones from the delta..... yup. Da1 and Da2
ignoring the un-necessary bits:
L1 to Sa2
L2 to timer1
timer2 to Sa1 and Da1
L3 to timer 3 and Da2
So: at start, we have short circuit between timer2 and timer3, effectively putting L3 and L1 across the star contactor; with L2, and L3 supplying the timer wires 1 and 2 (via the coil of the delta contactor.)
My thinking was that, when the switch opened after the time delay expired:
timer 2 has become O/C from timer 3. Delta coil is now supplied via L3 and timer wire 2, through the timer load and wire1,from L2
BUT.......
The moment the star contactor opens; the delta "begins to move", however for whatever reason (think I`m losing operating voltage on the timer), timer resets, wire2 from the timer shorts to L3 again, and the star contactor closes again, for a new timing cycle.
Somebody tell me what I`ve missed. Please?
KME
