Oil-filled Capacitor capacitance question

[RJSakowski]

The summer of '66, I worked for a company that made distribution transformers. My job was reclaiming units that failed electrical testing. The first task was disconnecting the connections from the transformer to the feed throughs to the outside world and removing the mounting fasteners for the transformer. This involved dipping my arm in the transformer oil up to my elbow. I'm sure that at the time, PCB's were used in the oil formulation and that was 57 years ago.

I have had a melanoma removed from my back but not in an area that ever came in contact with CB laden oil. It is more likely due to exposure to the sun in my early years. Since the surgery, I have a semiannual head to toe check by my dermatologist with an all clear so far.

Everyone has to make up their own mind about risks but for me, an occasional exposure to oil containing PCB's doesn't concern me.

 

[hudstr]

I ended up buying a rpc panel which is basically everything you need for a rpc except the motor. It would have been a tight squeeze in the existing enclosure if I tried re-using it. I'm sure it'll work just fine if I ever need it in the future or if I sell it.

I've done a lot of researching and decided if I am going to be wiring anyway, I might as well install a vfd. Being able to stop the spindle in 2 seconds is worth the cost to me and dialing in rpm is an added bonus.

 

[woodchucker]

I ended up buying a rpc panel which is basically everything you need for a rpc except the motor. It would have been a tight squeeze in the existing enclosure if I tried re-using it. I'm sure it'll work just fine if I ever need it in the future or if I sell it.

I've done a lot of researching and decided if I am going to be wiring anyway, I might as well install a vfd. Being able to stop the spindle in 2 seconds is worth the cost to me and dialing in rpm is an added bonus.

I thought speed control was the number 1 reason for a vfd. Why the need to stop the spindle ? Are you doing something special?

 

[mksj]

I thought speed control was the number 1 reason for a vfd. Why the need to stop the spindle ? Are you doing something special?

I thread typically at up to 600+RPM, and am often turning to a shoulder or internal deep boring/threading, knowing that my lathe will stop quickly and repeatability is just as important as the speed control. The main reason I installed a VFD on my first lathe was that there was no foot brake, I felt it was a significant safety addition, more so then the speed control.

 

[woodchucker]

I thread typically at up to 600+RPM, and am often turning to a shoulder or internal deep boring/threading, knowing that my lathe will stop quickly and repeatability is just as important as the speed control. The main reason I installed a VFD on my first lathe was that there was no foot brake, I felt it was a significant safety addition, more so then the speed control.

ahh, ok. first I didn't realize it was a lathe, I didn't read back. Second, that makes sense. I just installed a foot brake.

 

[hudstr]

Sorry I should have mentioned that. This is for a south bend heavy 10. A foot brake is something I'd like to have but I need to get better at welding first. For now I'll settle for the motor braking from the vfd.

 

[tq60]

Here is our foot "brake"...

The white box contains the VFD, the foot bar activates a second stop switch.

All attached to a sub-frame that uses the chip Pan holes.

Original drum switch above and behind chuck, it controls VFD.

Lathe is SB14.5 with factory 3 phase.

Sent from my SM-G781V using Tapatalk

 

[woodchucker]

Here is our foot "brake"...

The white box contains the VFD, the foot bar activates a second stop switch.

All attached to a sub-frame that uses the chip Pan holes.

Original drum switch above and behind chuck, it controls VFD.

Lathe is SB14.5 with factory 3 phase.

Sent from my SM-G781V using Tapatalk

is that a load meter (ammeter)?

 

[rwdenney]

Here is our foot "brake"...

The white box contains the VFD, the foot bar activates a second stop switch.

All attached to a sub-frame that uses the chip Pan holes.

Original drum switch above and behind chuck, it controls VFD.

Lathe is SB14.5 with factory 3 phase.

Sent from my SM-G781V using Tapatalk

Sorry for crapping on the thread for a moment, but that looks nice. My SB14-1/2 uses a 2-hp single-phase motor, wired (now) for 240. It doesn’t stop in two seconds, though no journal-bearing lathe is going to spin very long after power is cut. I’ve been thinking of adding a magnetic run switch, which would render the slightly under-rated drum switch for directional control only. (No arcing if not switched under power.) That would at least put the switch in a similar spot to your VFD, making it easily accessible from the front.

Rick “more like 5 seconds from 1000 rpm with a heavy chuck” Denney