View Full Version : Homebuilt RPC based on European motor

11-15-2006, 07:53 PM

I've finished construction and initial tests of a 4HP (2.9KVA) RPC based around an IEC motor that I removed from my tablesaw when I swapped motors. The idler is an ASEA 4HP 2890 RPM, 230/400V 50Hz, IP56 motor. Using Matt Isserstedt's basic design and Paul Cataldo's modifications as a basis for the electrical design as well as advice from here and the Practical Machinst forums, I made slight modifications to reduce the parts count and to match the parts which I had to hand.

This is a link to my schematic.

http://img230.imageshack.us/img230/1690/rpcschematicsmallerv1ei3.th.png (http://img230.imageshack.us/my.php?image=rpcschematicsmallerv1ei3.png)

I have completed phase balancing but have yet to buy the proper sized fuses before I can perform a load test. As soon as I can locate a source for the fuses I need, I'll be able to complete my project.

Funny enough, the run caps for balancing were very small; nowhere near the 15 uF per HP most others homebuilders have used for their designs when employing NEMA framed 60Hz motors. Possibly the initial good phase balancing is due to the high RPMs of the idler or to the construction differences between IEC and NEMA motors or possibly a 50Hz idler running on a 60Hz feed. In any case, the idler is smooth and quiet no-load. I'm optimistic for the load test.