Most excellent vid, sir! You helped me immensely! I had so many questions regarding wiring a VFD and between you, AvE and mrpete222, I found answers to them all. Thank you so much!
Nice work Stan, apart from one thing.... The USA's centre tapped single phase domestic power distribution causes endless confusion. Two wires can NEVER be anything but SINGLE phase. Two phases with a 90 degree phase angle was used at one time for power distribution, but used 4 wires. A very inefficient use of copper!
Hi mate. Thanks for that info. Those over load protectors, are they the RCD kind? I think I have not come across those here in Australia. But if I can't get something like that, I will have to use some relays and RCD units. Marcel.
Thanks for the info. I have a couple motors and was wondering if I could just get one which was rated for the higher HP motor and use it on the smaller. Your video answered that.
Hi Stan, more great info on the VFD's very informative video, looking forward to the next installment. Out of curiosity, do those overload blocks protect from a thermal overload, or is the amp draw a different situation? Thanks ....... Mike
Hi Mike, Motor overloads heat very slowly so they arent really appropriate for short circuit protection, they have to be able to hold during inrush and motor starting conditions, fuses and breakers are designed for short circuit protection. In the most basic terms, fuses and breakers protect wires, overloads protect motors. Thanks for the view and comment. Stan
Stan, what a "Video JUST in time." I bought a Covel 10-PH grinder. 1 HP for the spindle and a 1/2 HP for the pump. (The pump BTW is a GM power steering pump. Covel was in Benton Harbor, MI) To say this is a rare bird is an under statement. I ordered a manual for a 10H. I hope it has similar wiring. Anyway, the question. Do I wire the VFD into the motors directly, skipping all the other circuits? Or can it be hooked into the main power cord? Your video on truing 2-4-6 blocks got me on the road to a grinder. I just wish this wasn't such a rare bird.
Veiy very well done. Agree you need to add HP of motors to derive total VFD HP. Do not forget to add nameplate currents also to ensure VFD has adequate "ampacity". Derating VFD is an issue when using VFD designed for 3 phase input on only single phase - yes it can be done. BUT you are using only two of the 3 rectifiers in the bridge rectifier so a derate to (I recommend) 50% should be just fine. One very small techy nit picky point. There was two phase decades ago - 90 degree phase angle - all gone now. Today almost all single phase is derived from two of 3 phases - which is why people call it two phase. It is most properly single phase - which if you put an O scope on it you get a single 60 Hz trace for both current and voltage - if scope can trace two signals. . I would recommend finding the contact ratings of the contact you are using for oiler. They do not give you big contacts and you may burn them. You may wish to use an interposing relay whose power contacts are fed from 5 amp fuses and coil is fed from 16 and 17 on VFD. The other thought on oiler is you may not want it to run all the time so a manual OFF switch may be considered. For me it would mainly be a housekeeping consideration ie keep mess to minimum - bit of wasted oil is no big deal in my mind. IF you open up the oiler I would like to see the innards. Dan Bentler
Hi Dan, The oiler is a 6 watt clock motor that spins @ 8 RPH, so it self oils 8 times an hour, the wattage is so minimal I didnt see the need for adding a relay to carry the current. Thanks for the view and well thought out comment! Stan
Stan you r too much... That is very good info to share. How does one use a VFD for lathe, mill starting with 120 V AC?? I think you need to have 3 phase motors on this setup. Can you make a video on this process?? Thank you again Manny
I have a eStop switch, motor contactors, relays, fuses, overloads, a standard IDEC red handle disconnect power switch and several supervisor key switches along with some semi-fancy stuff, pilot lights (green)/(red) and a pair of paddle buttons, anti-tiedown, fun stuff. I use Autotmation Direct.
well, it's for a machine that had very terrible control set up and the wiring of that control was about as horrid or worse.. + unsafe so I had to do what I had to do to set things right.
Nice expo on rigging a VFD for two motors. If I had a quibble, I would prefer to see a two-pole circuit breaker for that oiler motor. With fuses, a fault usually blows one fuse, leaving the other 220 wire hot. With a two-pole breaker, a fault in either line shuts off both wires. Here's an example from McMaster-Carr: www.mcmaster.com/#3931t2/=y0aj7l
I know there are 3 wires with 220-volts single phase (4 if there is a ground). There are 2 hot legs and a neutral leg. Between the two hot legs you get 220 volts single phase. Between any hot leg and the neutral leg you get 110 v.
