Wiring Powermatic 3520B

[Mike Maffitt]

Hey All,

I just received my new lathe and I have a wiring question related to 220v for the machine.

The inverter on the Powermatic 3520B ships with a 3 lead wire implying a 220v hook up is required. Can we replace that wire with a 4 wire lead to the inverter and run a 4 wire, 12-3 wire to a double pole breaker and have adequate voltage for the inverter to power the lathe?

Mike Maffitt

 

[Jim Evans]

I can't help with your question but another option is to call Powermatic tech support - I just had an issue with my lathe and they were really helpful.

The # is... 800.274.6846 - 7:00 a.m. to 5:00 p.m. (CST, Monday - Friday)

 

[KurtB]

Wiring 3520B

Mike,
I am not understanding why you wish to run 4 wires to the inverter? IIRC, the only reason to do so would be to run 3 phase to the inverter. Otherwise, it seems that you would only need 3 wires for the 220/1.😕

 

[Mike Maffitt]

220v newbie

Kurt,

Through a little misinformation I ran a 12-3 wire with 4 wires. If I dump one of the wires can I wire the machine from a dual pole breaker running 2 hots and a ground wire? I've never run 220v before but it seems this is how the clothes dryer connection is wired up.

 

[KurtB]

Wiring 3520B

Mike,
That should work as long as your run isn't too long. Just cut back the extra wire and tape it up so there's no chance it will touch anything else.🙂

 

[Mike Maffitt]

Thanks Kurt I appreciate your help. The run is a total of 45 feet from breaker box to receptacle.

 

[Alan Trout]

All 220 single phase circuits require to be complete 2 hot legs and one neutral/ground leg. In modern residential wiring where plugs are used, say for example a 30 amp dryer plug they now have a 4 prong plug. The extra wire is a safety ground and is not needed to complete the circuit but the safety ground is required in new construction. Typically on the appliance, say a dryer the extra ground is grounded to the chassis.

I assume at the connection to the VFD it does not have the facilities to connect the 4th wire or safety ground. However if you are using 4 wire SOO cord typically there is a black, red, white, and green wire. The black and red will be your power wires or hot legs and the white and green will be your neutral/ground legs. At the machine VFD you could hook both the white and green at the same post/lug if there is only one neutral/ground lug or you could make facilities to ground the green wire to the chassis. Or if you plug is 3 prong that you are using you only need 3 wire cord with no safety ground.

I hope this helps and is not more confusing.

Alan

 

[Bill Boehme]

Hey All,

I just received my new lathe and I have a wiring question related to 220v for the machine.

The inverter on the Powermatic 3520B ships with a 3 lead wire implying a 220v hook up is required. Can we replace that wire with a 4 wire lead to the inverter and run a 4 wire, 12-3 wire to a double pole breaker and have adequate voltage for the inverter to power the lathe?

Mike Maffitt

Your question is somewhat puzzling and I am not positive that I know exactly what you are asking, but I will hazard a guess. The controller is 240 VAC and that is the only operating voltage option available. If you are unsure of what you are doing then it might be best to enlist the help of an electrician or someone who is sufficiently knowledgeable. I need to ask if you know the difference between ground and neutral. Ground will either be bare or will have green insulation and is not to be used as a current carrying conductor -- its only purpose is safety. Neutral will have white insulation and is a current carrying conductor. Even though the neutral conductor is very close to ground potential, it is not ground and does not provide safety protection for certain types of failures. The ground (green) conductor is the one that you want to use. You could use a four-wire cable from the receptacle to the lathe, but leave the neutral wire unconnected at both ends. There is nothing to connect it to at the machine and you certainly do not want to connect the ground and neutral together at the machine. The other two wires (black and red) connect to the two high legs. For the building wiring, you will run the branch circuit wiring from the double pole breaker in the panel to the wall receptacle.The third wire will be the ground and not neutral. It is important that the color code of the wires in this branch circuit be properly marked to prevent some future mishap that could electrocute someone. The building wiring that you use will probably be done with what is commonly called Romex or Cirtex nonmetallic unshielded two-conductor with ground cable. It will have a black color coded wire, a white color coded wire, and a bare ground wire. Use either electrician's red color coding tape or color coding paint to wrap or paint about six inches of both ends of the white wire. This will identify it as being a hot wire so that someone doesn't grab it while power is applied thinking that it is neutral. Make certain that you install the correct style of 240 VAC receptacle in the wall. There are different styles depending on intended use and ampacity rating of the branch circuit, so what you use is not just some arbitrary choice.

 

[Bill Boehme]

All 220 single phase circuits require to be complete 2 hot legs and one neutral/ground leg. In modern residential wiring where plugs are used, say for example a 30 amp dryer plug they now have a 4 prong plug. The extra wire is a safety ground and is not needed to complete the circuit but the safety ground is required in new construction. Typically on the appliance, say a dryer the extra ground is grounded to the chassis.

I assume at the connection to the VFD it does not have the facilities to connect the 4th wire or safety ground. However if you are using 4 wire SOO cord typically there is a black, red, white, and green wire. The black and red will be your power wires or hot legs and the white and green will be your neutral/ground legs. At the machine VFD you could hook both the white and green at the same post/lug if there is only one neutral/ground lug or you could make facilities to ground the green wire to the chassis. Or if you plug is 3 prong that you are using you only need 3 wire cord with no safety ground.

I hope this helps and is not more confusing.

Alan

I am afraid that your post has confused the issue with incorrect information.

Neutral and ground are not synonymous, but you did at least imply there is a difference, but without saying which is which.

On the VFD controller, you have it exactly backwards. There is no neutral, but there is a ground and it serves the exact same purpose as it would on a lathe with a 240 VAC motor that does not have a VFD controller -- it connects to the metal frame of the lathe for safety purposes and is not part of any motor or VFD circuit.

Most importantly, you gave unsafe advice on connecting the neutral and ground together at the lathe. That creates a potentially hazardous situation and is a serious code violation. There is only one point in a building where ground and neutral can ever be connected together and that is at the service entrance panel itself. They can't be connected together at branch circuit panels and especially not at any device that is plugged into a branch circuit receptacle.

 

[Alan Trout]

Boehme, Sorry if you misunderstood what I was talking about or trying to get at. Being an inspector I fully understand what present codes are, and I also understand that many pieces of equipment do not have facilities for a safety ground. I understand that Neutral and ground are not the same thing but can have similar functions and very different functions as well. I was trying to discuss what he might be seeing if he is using SOO cord. You are correct the only panel to share a common ground/neutral buss is the main service. I also understand that a neutral is just as capable of carrying electricity as any current carrying wire. Being I did not quit understand what he was asking I was trying to open dialog to see what he was seeing. I am sorry for confusing the situation or misinformation that may have been implied. Nor did I want any codes to be violated. Sorry for any misunderstanding.

Alan

 

[Mike Maffitt]

Hey Guys,

Sorry if I confused the issue. I think the controller has confused the person I enlisted to help hook up my machine. I bought the 12-3 wire by his recommendation and had already pulled it before he showed up to make the hook-ups. I was trying to understand how a normal 220v power supply was run from the breaker box to the receptacle and what I understand is there are 2 hots coming from a double pole breaker and a ground run to the box which comprise the 220v feed to the receptacle. I understand there is no neutral wire involved in the circuit.

I know the electrician I enlisted is licensed. I just don't want him burning up my $3000.00 lathe because he doesn't understand the inverter and how it should be hooked up. It seems like a straight forward hook up to me.

Thanks for your feed back. I knew someone would point me in the right direction.

 

[Vernon Oberle]

4 wire circuit

Most of the time a four wire circuit for 220 is like when you run for a stove or dryer where they want a 220 circuit and a 110 at the same place without using another plug and wire run.