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GRAZIANO SAG 12 -24 VOLTS FROM UNIT

Thank you Jim. I've been advised that I should have 24 volts on the number 8 connector and -24 volts on the N connectior. Is this how your system is setup?
Thanks again
Chris
 
I have two different schematics Chris and my lathe is wired a little different than both. It looks like #8 is + 28 volts in reference to N (-)terminal when the motor is running # 5 is 28 in reverse and #6 in forward and 1 thru 4 are energized depending on your speed selection switch. I still do not understand that timer circuit with the 6 capacitors , the little relay does energize when the main motor is running but I don't know why they made it so complicated. Hope this helps. Let me know if you want any other measurements. Jim
 
Jim Thank you for all your help. My problem was a wire that had been seperated in the joy stick. I've learned a lot about my machine while tracking this problem. I have no idea why that this unit was created with so much effort put inte creating this timer circuit either. If there is ever any thing you need help with let me know buddy. I'll do my best to help.
Chris
 
 
I recognize that this is an ancient thread, so there may not be much point in posting this. However, I am an electrical engineer, and I spent a lot time yesterday analyzing the control circuitry on my 'new' Graziano SAG 12. Here's my understanding of how the control circuitry for the transmission works:
1. Control transformer has 2 secondaries: 24VAC and 32VAC. The latter is rectified to provide about 45 VDC.
2. 24VAC is used for relay coils and pilot lamps, and is switched by panel pushbuttons and some relay contacts.
3. 45 VDC is used for the 6 transmission coils, which include 4 speed selection coils, 1 forward coil, and 1 reverse coil.
4. The TIME DELAY RELAY has 2 functions:
a) One Normally Closed contact connects the speed selector circuitry directly to +45V, shunting the BALLAST RESISTOR BANK. This delivers a surge of current to any selected transmission coil. Once the relay times out, selected coils are connected through resistors, to reduce coil heating and control power consumption. It is characteristic of solenoid coils that they require less current to 'hold' position than they require to overcome friction and to close the initial magnetic gap.
b) A second NC contact shunts the OIL PRESSURE SWITCH to allow some time for oil pressure to rise, since the OPS otherwise disconnects all the transmission coils from power.

So, here's what happens when you operate the controls:
1. Motor ON button - Pressing this energizes the motor contactor relay. One Normally Open contact then shunts the pushbutton to latch the relay on.
2. Motor OFF button - Pressing this button opens the motor contactor relay circuit, resetting its latching action.
3. Speed/Direction stalk control -
a) Swinging it UP connects the Forward Coil to +45V
b) Swinging it DOWN connects the Reverse Coil to +45V
c) Rotation connects various speed coils to +45V

Provided that the OPS is closed, selected transmission coils will be energized, including a brief pulse of extra current until the TDR times out.

I hope someone finds this useful.
 








 
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