GBewley2
Aluminum
- Joined
- Dec 21, 2008
- Location
- Tennessee, USA
Your interest and advice both greatly appreciated on this problem:
I picked up a lathe running a 7.5 hp spindle motor along with some low voltage ancillaries. In order to run the lathe in my rural shop, I installed a used ARCO HD7 rotary phase converter, which is rated at 15 horses starting, total load 30 horses.
Installed the RPC day before yesterday and took measurements, which I have posted below, and fired the unit up and then turned on the lathe. On occasion the lathe started roughly, kind of growling and then taking off and getting to speed. I am sorry I don't have a better way to describe it. At first I thought the electromagnetic brake was the problem, so eliminated it, and finally in the end I totally isolated the motor from the rest of the machine and still have the problem.
Now here is the where I need some help. We took some readings as per the ARCO website installation instructions and came up with the following. Phase refers to T1, T2 and T3, after the RPC. Phase 3 (T3) is the MANUFACTURED leg coming out of the RPC. The other two are from the grid. These are voltage readings.
Phase 1 to Ground: 124V
Phase 2 to Ground: 124V
Phase 3 to Ground: 240V
Phase 1 to Phase 2: 254V
Phase 1 to Phase 3: 253V
Phase 2 to Phase 3: 285V
Do any of these figures lead any of you to suspect that the power I am providing the motor would create the problem? The manufacturer of the RPC said that the 254/253/285 reading was not a big problem but to me the 124/124/240 seems a bit strange. Frankly, I am an engine guy, not a motor (electrics) guy. Any input that those of you who are well-versed could provide would be greatly appreciated.
Right now I am really appreciating my simple old Logan lathe, I can tell you that.
Thanks in advance.
Glenn
I picked up a lathe running a 7.5 hp spindle motor along with some low voltage ancillaries. In order to run the lathe in my rural shop, I installed a used ARCO HD7 rotary phase converter, which is rated at 15 horses starting, total load 30 horses.
Installed the RPC day before yesterday and took measurements, which I have posted below, and fired the unit up and then turned on the lathe. On occasion the lathe started roughly, kind of growling and then taking off and getting to speed. I am sorry I don't have a better way to describe it. At first I thought the electromagnetic brake was the problem, so eliminated it, and finally in the end I totally isolated the motor from the rest of the machine and still have the problem.
Now here is the where I need some help. We took some readings as per the ARCO website installation instructions and came up with the following. Phase refers to T1, T2 and T3, after the RPC. Phase 3 (T3) is the MANUFACTURED leg coming out of the RPC. The other two are from the grid. These are voltage readings.
Phase 1 to Ground: 124V
Phase 2 to Ground: 124V
Phase 3 to Ground: 240V
Phase 1 to Phase 2: 254V
Phase 1 to Phase 3: 253V
Phase 2 to Phase 3: 285V
Do any of these figures lead any of you to suspect that the power I am providing the motor would create the problem? The manufacturer of the RPC said that the 254/253/285 reading was not a big problem but to me the 124/124/240 seems a bit strange. Frankly, I am an engine guy, not a motor (electrics) guy. Any input that those of you who are well-versed could provide would be greatly appreciated.
Right now I am really appreciating my simple old Logan lathe, I can tell you that.
Thanks in advance.
Glenn