BTW, the Jeffers pdf is
www.jeffersonelectric.com/pdf/3-PhaseVent.pdf rad74 — You probably have access to some UL-508
x[/x]–type enclosed-panel assemblers, so consider using some decent epoxy-potted 240x480—120V 55°C-rise machine-tool transformers like Micron Impervitran www.microntransformers.com/products/impervitran.php
or Hammond PH www.hammondpowersolutions.com/i_controltrantext.html#ph
and LPJ fuses in a Boltswitch PJ-series pullout block www.boltswitch.com/O-1374.pdf [Suggest avoiding CCs at 600V.] About 300VA of capacity per transformer {when wired 480:120 in an [i]open-delta autotransformer pair] is needed for each 0.65-ampere of 460V-3ø
balanced load. (Motor count and auxiliary load not specified in thread.)
Use common sense, sensible troubleshooting methods and check ø·ø hiside voltages before heatup, and after heatup check ø·ø hi- and loside voltages, and noload hiside currents. Then check for balanced hi- and loside ø currents and ø·ø voltages with all running load applied. Check for even, non-excessive transformer heating and sniff everything carefully after running for ½-hour, too.
Understand that [for the last 40 years in particular] 1ø TENV and TEAO appliance motors are
value{!¡!}-engineered to run very close to the edge even brand new—with auxiliary windings in PSC motors and start windings in other 1ø motors of smaller-gauge conductor, making them physically harder to protect (ergo, quicker to fry) through thermal damage than “main” windings. 3ø squirrel-cage-motors don’t have that crippling limitation leading to a virtually universal M·R·O habit of nothing other than ready disposal.
[ Also, there is a wonderful but {in some circles} slightly lewd term for these components—they may be referred to as ”
((insert national-brand-name absorbent wimens-health’n’freshness item that men really, really hate to buy at 1AM in a QwaKKy·Mart where your sniffling nephew works graveyards, while having to use a pers'nl check—forgetting all three *mandatory* IDs no less)) type of moter.” ]
[This message has been edited by Bjarney (edited 04-01-2005).]