Phase converter

Well I just did a little experimenting with my phase converter.
I have a 5 hp 3400 rpm idler motor with 100 mfd run capacitors and 100 mfd
additional for starting. My shop is powered through a 90 amp breaker and my
phase converter is off of a 30 amp breaker under that.
I started my three Bridgeport mill spindles (three 2 hp motors) and my 5 hp
YAM 14 inch lathe. So far so good, I have 11 hp of machine and 5 hp of
converter running with no problem. Next I reversed the spindle motor on the
lathe with out first stopping it. That is what it took to pop the 30 amp
breaker on the phase converter.
All of this without dimming the lights. I am using 8 gage wire from the
breaker to the phase converter and 10 gage to each of the machines. It looks
like all I need is a little bit bigger breaker on the phase converter.
Darrell