This project is a 3-phase step-down transformer to power two high-temperature fans. 
It contains 3 single-phase transformers wired in a delta-wye configuration which
drops the voltage to about 100V per phase to slow the fans down a bit.

===  Proposed Upgrade June 2011  ===

The system is being upgraded to handle 4 fans.  The power supply (transformer) box
will be replaced by a 3-phase 
[http://en.wikipedia.org/wiki/Variac#Variable_autotransformers Variac]
 
* [http://ohm.bu.edu/~hazen/nEDM/FanControl/St100_200Mech.gif ST200 series variac mechanical drawing]
* [http://instrumentation-central.com/staco/EngineeringDrawings/291-3.pdf Engineering drawing]
* Schematic for Variac Box: [http://physics.bu.edu/~chill90/Variac_Fan_Power_Box_Final.pdf PDF]
• [http://physics.bu.edu/~chill90/Variac_Fan_Power_Box_Final.sch ExpressSCH]
* Note: All switches, temperature controllers, and the variac will be mounted on the box''s front panel.  All plugs, input cables, and fuses will be mounted on the rear panel. 
* [http://physics.bu.edu/~chill90/EDM_BOM-Variac_Box.pdf Bill of Materials for Variac Box]

===  Existing system as of May 2011  ===

* Power Supply (transformer box) as built: [http://ohm.bu.edu/~hazen/nEDM/FanControl/Fan_Power6.sch ExpressPCB]
• [http://ohm.bu.edu/~hazen/nEDM/FanControl/FanPower.pdf PDF]
* [http://ohm.bu.edu/~hazen/nEDM/FanControl/TempSwitch.pdf TempSwitch.pdf]