Power Supply - Transformer with Power Cord 28 volt DC ( direct current, and not AC, or alternating current ) for North Star larger models, and has PN 7337482.
Effective August 2016 NEW Part Number is 7351054.
AND This Transformer now is 24 volt DC and has square body ( not rectangular ).
This is the MANUFACTURER direct replacement for all DC transformers.
NOTE: Older models used Transformer 7275907 ( 24 volt AC.. alternating current, not DC, with power cord ).