Good, OK. Thanks! I removed the drum switch completely and wired the VFD directly to the motor. Problem solved, definitely the switch contacts were hinky. It starts right up at any speed I dial in, and I am also able to change motor speed after it starts with the push button panel, faster or slower. I can already see that I will want a potentiometer at some point, the push button method is a bit of a nuisance. Not so bad if using Hz to vary speed, but then I like the RPM readout better. Huangyang models I found on Youtube were very similar, I thought the same thing about this being a knock off from those. If anyone ever wants a reference for the panel setups, here's what was used in this case. BTW the 2HP motor I use is rated 6.5/7.2 A. My shop non-load, line voltage measures 250v. My wiring is solid 12g for only about 10 ft. from the main breaker panel, then transitions to stranded 12g in flex conduit from there for another 5 ft to the VFD, which is mounted on a swivel to the back wall so I can swing it out of the way, or leave it where the old drum switch was, and keep it isolated from machine vibration (the wiring fits into the VFD terminals w/o trimming down strands).
For non-default VFD settings, you only need to play with Pn1, 2, & 8-12 (and maybe Pn17).
Pn1: Set at "1" and it will display Hz. Use any other number and it displays that chosen maximum RPM.
Pn2: Set the line freq to 60Hz
Pn8: Set acceleration time to 5 seconds
Pn9: Set deceleration time to 8 seconds
Pn10: Set maximum running freq to 120 Hz
Pn11: Set minimum Running freq (I used 5Hz, which is ~160RPM).
Pn12: Set motor freq rating to 60 Hz.
(Pn17: Set braking voltage from 1-100v. Default is 30v. I tried both 30v and 100v, found no difference in decel braking or fault avoidance, so I think this parameter is for the auto-reverse function which I don't have any use for.)
There are additional setups for 7 multi-segment speeds, the one-touch stop-and-reverse mentioned, torque compensation, 2nd decel time, and choices for controls, panel vs. external etc.
This motor does require 5 sec acceleration time for a full-speed, 120 Hz start or it will trip the internal fault. If using electric braking, also from a full-bore stop, it requires minimum 8 seconds decel to avoid tripping the fault. I set max Hz to 120 as recommended above, and line Hz into the panel at 60. Apparently this allows that the freq/RPM curve is correct.
I wish I had done this when I first got the mill. Some guy I bought it from had jury-rigged the wiring instead of repairing the faulty drum switch. When I repaired the switch and then put it all back together the way this guy had it wired it fried the motor. I had to buy a very expensive, new motor, and then figure out from scratch the RIGHT way to wire up the crazy Dahlander motor. Had I just bought a VFD in the first place I could have saved myself a lot of time, money and anger management classes. (No, I didn't really go into anger management classes, and I still yell very loudly and cuss up a blue streak.)