Yes! sorry, I've calmed down after a night's sleep...
Your schematic from #20 looks to be the one. I only have one indicator lamp, too. I agree with not thinking the light bulb is the problem, I'm just keeping it in the back of my head as I tinker.
I saw from your #20 post, the KA is energized while no direction is selected, correct? Then, did you mean that when a direction is selected, KA de-energizes (mag releases) and the KA1 or 2 energizes? Was that the safety system you referenced? (I'm just trying to understand all of it properly). If that is the case, that's what happens. When power is turned on, the KA energizes...when a direction is chosen, KA de-energizes, but nothing happens. I felt like when I chose a direction, and KA de-energized, I could push in KA to get movement, not KA1 or 2. At any time with only power on and no direction selected, I can press KA1 or 2 to initiate the motor.
The pathways and wiring all make sense as I look them over, I think I get lost with all the wiring that goes back and forth between the contactors. I assume it's done to prevent accidental spindle starts, switching directions accidentally, etc...for safety. I kind of wish I could just get new guts and wire it myself, so I know it all...
Thanks for dealing with me on this. I'm not used to needing help on anything...feels weird.
-Stephen
KA is used as a safety interlock, this ensures that your direction selector on the lathe apron is in the neutral position, the intent, that the spindle will not spin until you are "at the wheel" wanting it to go. Its intent is in the event of a power outage, the lathe will not come back on until you move that lever back to the off position.
So NO, KA must remain energized when you select a direction of spindle. If it does not, then there is some issue, either its coil has overheated and requires excess current from the 24 volt transformer to remain engaged, or the transformer overheated and can't provide the power to keep it engage, (or a loose connection), when you select either the forward or reverse contractor to engage (Km1, KM2). Loose connections can look the same. And as it was working before you brought it home, this is very possible. Or you are not powering it from the same voltage. I think you indicate this is a 220VAC system. If so, then ensure the motor is wired for 220. The nameplate shows Low and High voltage wiring chart, so ensure you have this correct.
I've seen where they only change the wiring to the run windings, as the start windings are in the circuit for such a short time, that the motor design does not change them between high and low input voltage. If you haven't already looked up how the motor direction is changed, one of the windings, typically the start winding, has it's leads reversed, that is what the 2 contactors are doing (flipping the start winding connections). The start winding has a start capacitor in series, as well a centrifical switch that opens the connection to it after the motor has spun up to speed. You can typically hear this, as well when the motor is coasting to a stop, hear it click back closed.
If you look up "3 wire stop start circuit" with google, you will see what the KA relay circuit is doing. The coil can only get 24v power if the direction switch is not selecting FWD or REV. That is the 2 switches marked SA1 and SA2 on the diagram. That is what initially powers the KA solenoid coil to close the contacts. Note once this occurs one of the KA switches, then applies the power to the coil to keep it energized
Quick note on start stop push button control:
(in a 3 wire start stop button circuit, the start switch, a normally open switch, powers the relay coil , and an auxiliary switch of that relay, then keeps the power going to it through the stop switch which is normally closed, when you press stop, the power is removed from the coil). This KA circuit is very similar.
Then in series with the direction contactors is one of the 3 KA switch contacts. There is one in the circuit for REV coil circuit, and one for the FWD coil circuit.
Note that the SA1 and SA2 are what is called single pole double throw switches, as when you move the lever for forward or reverse, the connection that would normally power the KA coil, is opened, and the 24 volt from the transformer is redirected to the FWD, REV contactor coil, but since a switch contact of the KA relay latches the 24 volt to the coil, it stays engaged. And there as others have said, is an interlock to ensure you don't energize the FWD/REV contactors simultaneously. KM1 and KM2 are the coils for motor direction contactors, that you have figured out how to manually close, and have proven there is no issue with your motor.
If the KA relay ever opens, as you indicate, when selecting motor direction, the issue is either a loose connection or a bad KA coil, or 24 volt transformer.
Please check that the motor is wired for 220VAC. Hopefully you have all the wires still connected properly, then verify that KA can close, and does not open again when you select motor direction. If it does check the KA switch that closes to keep the power to the KA coil. Check what the 24 volt transformer voltage does when KA is energized, and you then energize KM1 or KM2 for motor power. If it does not droop excessively then either a loose connection or a bad coil needs to be determined. Check what the 24 volt is at these coils. You need to track down the fault.
Again KA must stay in the circuit as it has switch contacts in series with the motor contactor. You need to figure out why it is dropping out when you engage motor direction.
