Testing 41B & 42B PTE Interlocks

The Power Tool Ejector system used in many Lucas machines for tool retention is a proprietary system used only by Lucas.

Air pressure is used to eject the tool from the Spindle and to hold the air cylinder in a retracted position and away from the actual PTE mechanism.  Spring washers power the actual Clamping.

The air cylinder MUST NOT contact the PTE mechanism when the spindle is rotating or considerable damage will be done, not to mention the personnel hazard that would occur is the tool was 'thrown' from the Spindle.

The electrical system provides interlocks to prevent the Spindle Rotation from being started if the PTE is in the eject position and also to prevent the PTE from ejecting if the Spindle is rotating.

Of course, the interlocks could fail due to electrical problems, which now poses the problem of "How do I check the Interlocks, since if they have failed, I will destroy my PTE system during the testing"?

The answer is to simply remove the main drive belts that connect the main motor to the Speed Gearbox.

Sooner or later, an electrician will suggest that an easier way to prevent Spindle Rotation from damaging the mechanism is to simply remove the coil wires from the Main Motor Starter in the electrical cabinet.

DON'T DO IT!

The motors of 41B and 42B machines are equipped with 'speed sensors' on the end of the motor opposite the belt sheave.  The electrical system MUST 'know' if the motor is ACTUALLY rotating for the interlocks to function properly on most machines.  Removing the coil wires from the motor starter can result in an improper test, whereby the interlocks are deemed to be functioning properly when they are, in fact, not working at all!
 

After removing the main drive belts, proceed as follows to test the PTE interlocks:

1. Select Spindle rotation and verify that the motor is running.
    
2. Attempt to operate the PTE system to Eject.
    
3. If the system will not eject - the first interlock is working.
    
4. If the system will eject - the interlock is NOT working.
    
5. Stop the Spindle rotation.
    
6. Eject the PTE system.
    
7. Attempt to start the Spindle rotation.
    
8. If the Spindle Rotation will not start - the second interlock is working.
    
9. If the Spindle rotation starts (look at the main motor), the second interlock is NOT working.
    
10. De-select Spindle rotation start - (or select Spindle rotation Stop).
     
11. Change gear ranges and attempt to shift the gears.
     
12. If the Spindle rotates for a 'Shift Jog' (look at the main motor), the third interlock is NOT working.
     
13. If the 'Shift Jog' does not cause Spindle rotation, the third interlock is working. Not all machines are equipped with the third interlock.  Look at the electrical prints.
     
14. Clamp the PTE system.
     
15. Start the Spindle rotation.
     
16. Select the PTE system to Eject.
     
17. Stop the Spindle rotation.
     
18. The main motor should physically stop rotating BEFORE the air valve 'fires' to eject the tool.
     
19. If the main motor has completely stopped rotating before the air valve 'fires', the time delays are properly adjusted.
     
20. If the air valve 'fires' before the main motor has come to a complete stop, there are usually time-delay relays available to cause the air valve to 'fire' later.  Not all machines have time-delay relays for this function. Look at the electrical prints.