Thanks to all for this very useful advice!
(reply to LionelHutz)
The Danfoss 5000 spec shows scope traces of relatively smooth sinusoisal motor current from its PWM output scheme, and does not seem to require line reactors beyond what is built in, but does not use the term "active front end"...
You are correct, I was thinking of the soft starter circuits; the VFDs I have seen use an open loop V/f ramp for constant torque up to Vmax. Jraef has suggested a Closed Loop Vector drive which I will look into further. I will look for one with an active front end.
Have now tested Alcopanel, a 4mm laminate of noncombustible polyethylene between thin aluminum sheets, and following hammering with a 3/4 plywood backing it retains remarkable fire resistance, beginning to delaminate at the edges after 15 minutes of propane torch. The aluminum does not melt in...
(response to cncad areospace):
The winch (Thern 483) is 2 hp (4000 lb) loaded <3000 lb with 120:1 worm drive and 3-phase AC motor with electric brake. Back-travel can be restrained with safety cable and large chocks, so have 1-phase 240V AC non-brake alternate motor to fit, but would rather use...
Thanks for your ideas!
Polyurethane foam-core panels may not delaminate after many impacts, but may not respond well to extended exterior burning.
I have tested 1-inch exposed-aggregate hard stucco over expamet, and even without sheathing support it does stay together under sledgehammering and...
Thanks very much for your input!
The motor is to drive a winch pulling an amphibious cargo trailer up a steep hill on an island, where system weight is significant and power is supplied by generator (to be sized by your very useful FAQ). A generator sized for DOL starts will be very hard to...
I need full load starting torque from a 3-phase 120-208/230 motor, and want to use a soft starter (Gavazzi RSE4812-B) on a hybrid phase converter (GenTec/Baldor) to limit current on the 1-phase 240V line. Is a heftier 3-phase supply a better solution?
The phase converter is a hybrid rotary...
I am considering designs for light weight building exterior wall panels which will resist concerted efforts of vandalism and arson. Weight restrictions preclude masonry. Have considered metal plates to resist impacts, mounted on corrugated venting layer for shock absorption. Also considering...
