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TB049 Rev1 Using Phase Converters
Overview
When considering the use of a phase converter to supply three phase power for control operation the
following guidelines must be followed to prevent control system damage and unwanted problems from
occurring Damage caused by failing to comply with these guidelines is not covered under warranty
Guidelines
1 The phase converter must be of sufficient capacity to handle the motor HP load as stated on the control
identification tag In most cases the control identification tag can be found on the outside door of the main
control cabinet often referred to as the Magnetics enclosure
2 A qualified electrician must install the phase converter according to local electrical codes
3 The synthesized leg sometimes referred to as the generated leg or "the wild leg" must be connected to L1
on the main service disconnect switch Refer to the illustration below The control system uses L1 for powering
three phase motors such as the spindle motor or flood coolant motor and for powering Centroid?s SD3 and
SD1 drives The phases connected to L2 and L3 are used to provide power for the rest of the control system
including the computer and motor drive amplifier circuitry which is why the wild leg cannot be connected to
them without damage or malfunctioning of the control system
4 For systems with SD3?s or SD1's Remove the wire that runs from the three phase rectifier to the wild leg
This will allow the drive to run off of single phase and keep the voltage at the correct level
Document History
Rev1 Created on 1998 08 25