CNC Lathe
Posted by
James Owens
on 2003-03-09 17:06:40 UTC
Hi,
I have a lathe with a tool changer and it is malfunctioning. I should first
tell you what happened. I was working on the live machine taking voltage
readings to find another fault and while doing so dropped my meter. The wire
coming from the power supply dis-lodged from where I had it pegged and
shorted out on the metal work. The result, I let some smoke out of the
transformer.
Anyway I connected it all back up, after fixing the fault I was looking for,
and a huge amount of smoke can out of the rectifier. While this was
happening I think I heard the tool changer doing something. The rectifier
blew before I got the power off. Having replaced the rectifer and checked
the power resistors in the supply I again connected up and operated the tool
changer. It was slow with no power, I was able to stop it going around with
my hands.
This machine has a 555 timer to give pulses for both the X and Z axis. The
pulse and direction signals from both the axis go through a pair of relays
on the tool changer board. There is no seperate pulse generator for the
changer. The changer runs backwards until it hits a switch of some kind and
then runs forwards until it meets a stop, all this is inside of the changer
and I've not been in there yet.
The pulses then go into an SAA1027 stepper driver and out through four
2N3055's.
I have metered the motor and get the same reading on all windings. No
problem there I think. I have checked the 2N3055 and associated doides and
all seem ok. I have checked all the wiring that I can get at easily. The
transform seem to be putting out the correct voltage but I haven't been able
to check it under load. There is no smoke coming from it.
Can someone point me in any direction, I'm stumped.
Regards,
Terry
I have a lathe with a tool changer and it is malfunctioning. I should first
tell you what happened. I was working on the live machine taking voltage
readings to find another fault and while doing so dropped my meter. The wire
coming from the power supply dis-lodged from where I had it pegged and
shorted out on the metal work. The result, I let some smoke out of the
transformer.
Anyway I connected it all back up, after fixing the fault I was looking for,
and a huge amount of smoke can out of the rectifier. While this was
happening I think I heard the tool changer doing something. The rectifier
blew before I got the power off. Having replaced the rectifer and checked
the power resistors in the supply I again connected up and operated the tool
changer. It was slow with no power, I was able to stop it going around with
my hands.
This machine has a 555 timer to give pulses for both the X and Z axis. The
pulse and direction signals from both the axis go through a pair of relays
on the tool changer board. There is no seperate pulse generator for the
changer. The changer runs backwards until it hits a switch of some kind and
then runs forwards until it meets a stop, all this is inside of the changer
and I've not been in there yet.
The pulses then go into an SAA1027 stepper driver and out through four
2N3055's.
I have metered the motor and get the same reading on all windings. No
problem there I think. I have checked the 2N3055 and associated doides and
all seem ok. I have checked all the wiring that I can get at easily. The
transform seem to be putting out the correct voltage but I haven't been able
to check it under load. There is no smoke coming from it.
Can someone point me in any direction, I'm stumped.
Regards,
Terry