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meopm
05-17-2011, 12:20 AM
I have a home made 240v RPC that is tuned to less than 10% between each leg. I recently inherited a Gorton I-22 mill that requires 208v, the machine is in mint condition and I do not want to damage the electronic panel as everything in it is original. My question is will placing a couple of 24 volt buck transformers (one between each line and the manufactured leg) harm the machine? This would reduce the voltage to around 216v, well within the 10% range. The machine has several DC motors and a DC power supply for the power feeds that I do not want to damage.

MaxHeadRoom
05-17-2011, 10:31 AM
If the 3 phase is mainly for the spindle or motors, and the control and servo's are fed off of 1 phase in the panel, then just ensure that the 240v 1 phase that is passed through on your RPC feeds the 1 phase fed electronics in the panel.
This is the common way to ensure controller and servo are fed off the stable 240.
Max.

meopm
05-18-2011, 10:08 AM
Thanks Max
This machine uses the 208 3 phase to feed the spindle motor, coolant pump and I believe the Knee elevate motor. It looks like they are using Ln 1 & Ln 2 to feed the transformer and rectifier, the other two motors (Table feed & Spindle feed) are DC fed from the rectifier. I have been working off a schematic I got off the internet up to this point. I got lucky last night, I was digging around in the control panel and found the original build schematic tucked in behind the transformer. Very old and brittle but should be able to get it unfolded with a little patients.