Converting Dynasty Receptacle from 4-prong to 3-prong

[erikmannie]

The Miller Dynasty 210DX was the first welding machine that I ever bought, not counting the HF 110V solid core wire feed machine that I bought circa 2002 for $129.

Anyway, I wired the Dynasty plug as seen in the picture below.



And here is the wall receptacle. I have it pulled out because I was looking at the 6 AWG wires coming from the 40A circuit breaker.

 

[erikmannie]

Now I am standardizing all my welding machine plugs to be the same: NEMA 6-50P.

Here is the new wall receptacle that I bought today from Home Depot. This is a NEMA 6-50R. “R” stands for receptacle.



Here is the 6-50P plug (“P” stands for plug):

 

[erikmannie]

In the online manual, there are clear instructions how to wire up a 3-prong plug to the Dynasty. Unfortunately, I need to go to work now.

I will post pictures of the electrical work tomorrow morning. My Dad is coming over to oversee the work.

In the meantime, here’s a screenshot from YouTube and the Miller Dynasty manual.

 

[erikmannie]

The instructions in the manual or as clear as day. My Dad, who is a retired electrician, found it odd that one tapes off the red wire coming from the machine.

In any case, we are going to follow the instructions in the manual.

We have 4 wires coming from the single phase, 220V (residential) panel.

Does anybody want to weigh in on this?

 

[Nutfarmer]

What you are changing to has been superseded by what you are changing from. If you are updating I would go to the 4 wire plug. Just me. I am not an electrician so wait for one of the experts too answer. The extra wire is because they are separating the ground from the neutral. With the 4 wire plug it can also pick up 120 volts.

 

[erikmannie]

What you are changing to has been superseded by what you are changing from. If you are updating I would go to the 4 wire plug. Just me. I am not an electrician so wait for one of the experts too answer. The extra wire is because they are separating the ground from the neutral. With the 4 wire plug it can also pick up 120 volts.

My welding be on a 25’ extension cord now, so I want to standardize the plug so as to only need a single extension cord.

I could buy an adapter, but the adapters are pricey.

 

[mksj]

I had previous posted information on this in one of your previous threads on the question. The manual makes it clear that the welder can operate on voltages from 120-480VAC and single phase voltage or three phase voltage. So for three phase you would use black, white and red wires for L1, L2 and L3 respectively plus a ground. SIngle Phase is black and white fro L1 and L2 for 240VAC and would connect to N for 120VAC. The red wire is not used, for single phase and as indicated is taped off. The welder has an auto-sense and will configure the unit for the incoming voltage and phase w/o changing any jumpers. If I recall some people use and adapter jumper plug so they can used it in different settings/locations depending on the available power source.

 

[Asm109]

Never mind

 

[SLK001]

NEC says that you CANNOT use a WHITE wire for a hot line WITHOUT marking it with black/red tape at both ends. If the plug was for 110V, then that arrangement would be okay, but for 220V, not so much. But your plug is for 220V only. I'm curious as to how they are squaring this with the codes.

 

[mksj]

My understanding is that NEC applies to wiring to the socket, beyond the socket (i.e plug/cordage it is UL). NEC does have specifications for color coding as you have noted and also specific to socket/plug ratings for different applications, but with UL you can get away with different color codes and smaller gauge wire then would be allowed under NEC. I have a number of 15 and 20A 240VAC power cords that use white and black for L1 and L2, green w/wo yellow is ground. As a general practice I always use color electrical tape when using a white wire for a load, even with my electrical cords. That being said many electrical devices like VFD's and power supplies that allow a wide range of voltage inputs will often specify one terminal connection N and the other as L1 for 240VAC single phase input which reflects more ROS vs. US split phase.