Optimum 230/460V 3 phase Lathe & Mill

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Well-Known Member
HMEM Supporting Member
Jul 8, 2009
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One of the projects that I am doing with here at work involves some of the equipment in one of our maintenance machine shops.

We have an Optimum Optiturn D330 lathe that the nameplate claims is 230/460V 3 phase. We also have an Optimum Mill TMM200B, also nameplate rated at 230/460V 3 phase. Both of these are currently being powered off of an ancient 460V/230V 45KVA 3 phase transformer that needs to go for a couple of reasons. First, because the transformer is hanging off a wall that we need to move, and second because the transformer core is delaminating and buzzing - very loudly.

Our initial plan was to rewire the machines to 460V 3 phase, since that's what the majority of the plant runs on. This should have been a simple matter of changing the taps on the control transformers and rewiring the motors from 230V to 460V. We were able to determine that both of these units were sold by Grainger, but have since been discontinued. Other than that, there's very little information available on the web. Best laid plans of mice and men and all that crap.

THE LATHE - We were able to change the transformer taps on the lathe with no problems. We ran into trouble on the lathe motor. There only one junction box on the motor, with 3 wires on both the line side connections, and the motor side connections in this junction box. All the instructions in the junction box are in Chinese, as near as we can determine the instructions tell us how to hook up the motor in a Wye or a Delta configuration.

THE MILL - When we opened up the control panel for the mill we found that the manufacturer's label for the control transformer had fallen off and been disposed of. The prints that we found for the mill show that the transformer has a split secondary, with both 110V and 24V connections - but no other information on the transformer. The mill motor's junction box on the other hand DID contain the information for the 460V connections - in English.

So, we've got a lathe that we can't rewire to 460V because of the motor connections, and a mill that we can't rewire to 460V because of the transformer connections. I'm wondering if there's anybody out there with one of these lathes, or mills, with it running on 460V 3 phase that can show me what the required wiring changes would be? My electricians don't want to let out the magic smoke and neither do I.


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