Wiring headaches on my new grinder

[Dabbler]

looks good. then. You can easily go VFD or Rotary - Static converters work fine, but need to be matched to the motor current. I think they are pickier that VFDs that have active electronics in them.

 

[Bi11Hudson]

The drawing was quite well done. Your "chicken scratching" would have been fine. As a rotary converter, it is one as is. The only difference between what you have and a true rotary is the capacitor(s). And the switches. . . The capacitors would be split, one for "run", the other as a "kicker" or starting cap. The absolute values will vary from motor to motor so I can't advise what value to use.

Unless you need variable speed, I would not advise a VFD. What you have will work fine, as is. Just replacing the light switches with motor rated relays and a decent enclosure are my only concerns. A "3 wire start" would be a nice addition. And a relay for the kicker should you opt to add one. And, very important, decent insulation on the motor leads. But truth be known, I think you had already seen that. . .

.

 

[Eddyde]

It looks like your setup is missing a capacitor to be a proper static converter circuit.

I got that schematic from: a http://www.waterfront-woods.com/Articles/phaseconverter.htm
It was one of the articles I referenced when I did My RPC build, lots of info there and links other builds as well.

I also recommend giving a RPC serious consideration for this application.

To answer your question
"If I measure the draw with this SPC config running should I make that 2/3's adjustment"
That's a good question and I'm not absolutely sure of the answer but my thoughts are yes, if the motor is only putting out 2/3s the HP it will only draw the respective current. Also, the motor will only draw the its maximum current when under load, putting out its full horsepower.

 

[hustlebird]

The drawing was quite well done. Your "chicken scratching" would have been fine. As a rotary converter, it is one as is. The only difference between what you have and a true rotary is the capacitor(s). And the switches. . . The capacitors would be split, one for "run", the other as a "kicker" or starting cap. The absolute values will vary from motor to motor so I can't advise what value to use.

Unless you need variable speed, I would not advise a VFD. What you have will work fine, as is. Just replacing the light switches with motor rated relays and a decent enclosure are my only concerns. A "3 wire start" would be a nice addition. And a relay for the kicker should you opt to add one. And, very important, decent insulation on the motor leads. But truth be known, I think you had already seen that. . .

.

Thanks again for the wealth of knowledge you've shared. I think for now I will redo the wiring to be safer (fix connectors, replace switches, etc) but leave it as-is while I get to know this tool.

Everyone recommending the RPC - I hear you, just not something I can swing at the moment unfortunately.

Hopefully some first grinds soon! Appreciate everyone's help and input here.

 

[hustlebird]

One last addendum for historical purposes. I found this advertisement (https://mycompanies.fandom.com/wiki/Abrasive_Machine_Tool_Company) and it lists / shows the No. 3, and states "When equipped with motor drive, the machine is furnished complete ready for connecting feed wires. A one and a half horse power constant speed motor is used."

@sdelivery - You called it being big for its size