Have we verified he has a soft start and not a VFD? Some VFD's that must hold the shaft in place will send out just enough current to lock it.
All Variable Speed Drive controllers offer some sort of ramp-up and ramp-down facility, with respect to speed.
The original reasoning behind the VSD was for water pumps that used to blow couplings apart when started Direct-On-Line, giving the full force of water hammer through the pipes, one other reason was for production line conveyor belts, that used to jerk when started like this as well, it would also shorten the life of the belts.
Not to mention lost product sent flying off the belts, especially bottles and canned goods.
In my honest opinion, every electrician should own at least 3 of these things:
- A good solenoid voltage tester, capable of at least 150% of the the highest voltage you will ever work on.
I use a Duspol tester, for all of the low voltage stuff I do, it reads to 600VDC/750VAC:
![[Linked Image]](https://www.electrical-contractor.net/mt/duspoln.jpg)
- A clamp meter that has True RMS reading on it, most only read as an Average, this can bugger you up if there are Harmonics on the wire you are testing.
Once again, 150% of what you expect to be working with. - A Megger that will test motor windings, wiring and all sorts of other things, before your eyes.
Any electrician worth their salt owns one of these.
