Hello All:
It has been a long while since I posted here. Hoping somebody can help on a problem that just popped up on my South Bend 10L. I suspect the answer might already be somewhere in these forums; if so, would appreciate being pointed in right direction.
I've been running this lathe reliably and smoothly for several years using a VFD. The other day, the VFD failed (no output), and I got a faint whiff of smoke coming either from the VFD or from within the Furnas control box on the lathe. Today, I hooked up my rotary phase converter (that I use on some bigger machines) to the South Bend. After a few seconds of having 3-phase supplied to the machine, smoke started coming from the Micron Impervitran transformer within the Furnas box. I also heard a bit of sizzling from the transformer. Not good. Switched power off ASAP -- system had been energized for 5 to 10 seconds. I took a heat gun and shined in on the transformer and its temperature had risen from about 65 F to about 110 F. Double not good. After things cooled down, I tried it again, but the thing stayed cool and had no output on the low voltage side -- conclusion; it's toast. The little fuse on the outlet side showed zero resistance (not open), so I assumed it's OK.
So, question #1. How do I figure out what caused the transformer failure? Was it the VFD that took it out, or some other electrical component in the Furnas controls or switch? If it was the VFD, then I simply get another transformer and rely on the rotary converter -- job done. But, my concern is that the cause was something else within and another transformer will also fail even if I run with the rotary.
Question #2 (and this might be a stupid one, but I have to ask anyway). The transformer drops the voltage from 240 to 120 volts. The 120 is used for the starter contractor, a couple other thingss within the Furnas control box, and the lathe's work light. But since 120 is wired into the box anyway (one of the 3-phase legs), why isn't it used as is to run the starter, etc., instead of having to rely on a transformer to drop from 240 to 120?
Thanks in advance for any and all help.
dshore
It has been a long while since I posted here. Hoping somebody can help on a problem that just popped up on my South Bend 10L. I suspect the answer might already be somewhere in these forums; if so, would appreciate being pointed in right direction.
I've been running this lathe reliably and smoothly for several years using a VFD. The other day, the VFD failed (no output), and I got a faint whiff of smoke coming either from the VFD or from within the Furnas control box on the lathe. Today, I hooked up my rotary phase converter (that I use on some bigger machines) to the South Bend. After a few seconds of having 3-phase supplied to the machine, smoke started coming from the Micron Impervitran transformer within the Furnas box. I also heard a bit of sizzling from the transformer. Not good. Switched power off ASAP -- system had been energized for 5 to 10 seconds. I took a heat gun and shined in on the transformer and its temperature had risen from about 65 F to about 110 F. Double not good. After things cooled down, I tried it again, but the thing stayed cool and had no output on the low voltage side -- conclusion; it's toast. The little fuse on the outlet side showed zero resistance (not open), so I assumed it's OK.
So, question #1. How do I figure out what caused the transformer failure? Was it the VFD that took it out, or some other electrical component in the Furnas controls or switch? If it was the VFD, then I simply get another transformer and rely on the rotary converter -- job done. But, my concern is that the cause was something else within and another transformer will also fail even if I run with the rotary.
Question #2 (and this might be a stupid one, but I have to ask anyway). The transformer drops the voltage from 240 to 120 volts. The 120 is used for the starter contractor, a couple other thingss within the Furnas control box, and the lathe's work light. But since 120 is wired into the box anyway (one of the 3-phase legs), why isn't it used as is to run the starter, etc., instead of having to rely on a transformer to drop from 240 to 120?
Thanks in advance for any and all help.
dshore