Common questions: 1) Why didn't you run a neutral? This would require well over $100 worth of copper and a lot of work to replace cable in finished stud walls. 2) Why did you wire four outlets? There will eventually be three power feeds plus the DRO. 3) Shouldn't the white wire on the 240V input be black? Yes. It's common to color it black with a marker. I need to go back and do this.
I assume question 1 was the response to adding a neutral as apposed to building the neutral in on the original install? Question 2. Can't have too many outlets.
For some reason this brought back memories of when I worked on drilling rigs. I still touch stuff with the back of my hand when I'm uncertain about the electrical situation of something. When I'm not confident in what I've wired up, it's still my habit to start with back of hand before grabbing it, just to stack the deck in my favor. :)
"Of course not, that's silly... I did the project just to justify buying the Crimper"! Hahah!!! How many times have I done that too... I love your style James... Oh - & your content :) On a serious note, watching you & a few other workshop guys in the US, makes me sooo grateful for our power standards here in Australia. We have 240V single phase or 415V 3 phase (yes some other occasional setups which are different, but generally speaking). So you basically have 2 choices Single or 3 Phase. It's so much simpler.
James, I'm a controls engineer by trade and I'm impressed. This is just how we create control power in our three-phase motor panels. Sometimes I need a lot of 120V and spec out a larger external mount transformer, but when I need to add a convenience outlet for a programming laptop outlet, this is exactly what we use. Automation Direct is a great source for things of this nature.
“I’m not an electrician/expert” you crack me up. You’ve forgotten more things than I ever hope to know. You are one of the most analytical and detailed people I have ever encountered. Elon Musk should be afraid of you.
Aside from the excellent content of your videos, it has been impressive to see how much more skilled at editing and comfortable in front of the camera you've become. Many channels have trouble finding the balance between detail and respecting the viewer's time, and your effort really shows.
Hi James, really appreciate your projects, planning, execution, reflections and the extended effort to document for us all. Thank you for creating and maintaining the blog summary as first post. Bringing the gems to the top. Your viewers make some great contributions and normally we all have to mine for them or mostly, give up. and lose the opportunity of extended valuable input. Regards, Brett
All the holes in my wall will attest to my default of running new wires. This takes a brain like yours to figure out and will probably be very useful knowledge for later.
Great video. Thank you. This afternoon I'm going to go and check what I did with the neutral when wiring my 440v 3ph lathe. I was so excited about the lathe I don't quite remember the wiring. 😀
As always you explained it calmly and thoroughly and yet I was feeling entertained, not lectured. Congratulations to finishing the project ;) Self tappers protruding into a box of electricity would not be my ideal scenario, but since it is your home shop, all good!
James, Good job done your way I am not going to comment on the how because you did what is rite for your shop. I would do what I see as rite for my shop. Everyone else will try to blow smoke where they don't really know.
It's okay to remind us, to start doing those things we intended to do at some point. But good to see, that even someone as organized as you does procrastinate a little sometimes.
Nice vid. Just a suggestion-- it's bad practice to shoot a tech screw into a box. Having the sharp edge can cut your hands and your conductors. Use the appropriate length screw and put a nut on the inside (even having threads exposed is considered bad practice, over the years the exposed threads can wear through insulation, especially if the conductors move ( a flex run into a motor, etc.)
James, I liked the setup with the transformer and the outlets. My concern would be: what happens if you have to emergency stop the mill? The table will continue to move. When I did this for my mill, I pulled the 240v power after the contractor in the mill control panel, so the table would stop moving if I estopped the mill. I also understand there may be warranty implications, but I also worry about safety. Just a thought....
I am so glad that in our neck of the woods, South Africa, we only use 220v. No need to wire for both systems. But all in all, once again a nice informative video.
40 years ago when my shop was built as an extension on the rear of my home I ran the 240V mains in conduit and left a pull cord in the conduit. All additions I've made since then I always made sure I left behind spare pull cord. It sure beats having to dig out my wire snake when additions were made. On that note I can't imagine doing the original pull and deciding to save a buck by eliminating the 120V neutral. Not in this life! Wakodahatchee Chris (WA2ERQ)
Great post James (as usual). As the unit is shoved under the mill on a bare cement floor I suggest you put some rubber feet on it to prevent rust or a short if the floor gets overly wet. I had a brief fantasy of you cutting a big hole in the side of the mill casting to mount the box in, but that would be way too much work.
There is such a hole and panel already, but that's where the flood coolant sump is located, and I may use that some day, so the humidity in there will be around 100%.
I suppose that you chose the 20 amp rated outlets because they had the connection type that you wanted. Otherwise, it's certainly overkill as 15 amp outlets would have served perfectly well.
Great video, You might want to protect your box there on the floor. The shop that I work in had the same set up . The problem is metal chips down on the floor. You can imagine what happen. Drilling chips make a interesting moment.
15:03 "The funniest part is, you can't tell if that's a joke." Au contraire! I'm not falling for this trick. You gave us the answer a couple weekends ago. To quote "The other reason I wanted it is because it's a tool and I want to own them all" You are the man I perspire to be! 😁
Really like your transformer controller build. I also have a PM-935. Your build of materials list didn't include info on the fuses; part no, where purchased. Please, would you share those details?
nice work, a further safety step is that you can put the box on some feet (plastic or rubber) for elevation just in case of a liquid spillage on the floor (for whatever reason) especially that it is there on the ground with no direct line of vision. wish u all the best
Great video I didn’t know you could do this. I need to do this to my cnc conversion that currently uses a 240v plug for the spindle and a 120v plug for the control/steppers
Hi Clough I’m always looking forward to watch your videos. You usually have good explanation and reasoning for the decisions you make during the project. This time you skipped the part why you decided to connect the one secondary to the ground. The transformer you installed works also like safety transformer, until you ground one terminal. The grounding doesn’t increase safety - it decreases. That’s why in difficult situations you use safety transformer. If one secondary wire will short to metal part of the machine you will have the same case as you deliberately did. You are quite smart and I expected that it is some reason you did this. Thanks
Watch the video again. I explained it in detail. It's required by code because without bonding the neutral, there is no way for a fault current to re-enter the circuit to blow the fuse.
Hi James, I have 2 small issues, I know how much you love criticism…lol . I usually when grounding the neutral on the transformer use the green wire from the neutral term to the ground so just looking at the transformer it’s obvious that the neutral is grounded instead of having to see where the second white wire is going. I realize in your panel it’s easy to see but in more complicated panels it’s not as easy. Also with only a 250 va having 4 outlets might be tempting to overload it and blow the fuse.
Yeah, I think using a green wire here would be clearer. I was thinking about panels I've seen where white and bare wires go to a common bus bar. I plan to eventually use all four outlets.
What is the spec for the fuses you used on this project. FYI hubby installed it for our setup in Kenya so am able to use 110 tools like sanders, jigsaw etc. what I haven’t been able to use is my compound sliding saw or table saw. We have a Bussmann Fuse Current Limiting, Dual Element Time Delay, Midget Cartridge, Time Delay 2 Amp 250 V 13 and a 15 Amp but neither works for the saw. Is this the wrong fuse?
Very interesting video. I have seen dozens of 120/24V control transformer systems with the neutral of the 24V secondary bonded. I have not to my knowledge worked on a 240/120 control transformer with the secondary bonded as shown in this video, but it should be the same in principal. Will have to dig a bit deeper next time I see it (same should apply for three phase equipment with control xfrmers).
Great job (as always), very neat and professional looking. Silly question... was there not a 240v powerfeed model available? Or would that have been more hassel than it's worth?
James, I am happy to see you using ferrules. IMHO one fuse on each side is enough. All fuses I saw datasheets of allow 40% over current for 30 minutes. In your case 2A fuse will conduct 2.8A without problems. This means in case of short on the secondary side, the transformer will probably never go up to this value and the fuse never blows. Anyways, nice clean job!
Since both 240V input wires are live with respect to ground, two fuses are required. A short to ground in the coil, for instance, requires protection on both hot legs.
Howdy from Texas James, my question has nothing to do with the electrical but the square tubes under your mill. Did you find the table height just a bit to low so hence the additional height? If so what was the increase in height. Looks like 4" or so. Thanks
I had a similar problem in my shop, but I opted to buy a $27 voltage converter which came in a metal case with plugs, a switch, indicators and a fuse ready to go.
hi, just to ad that kind of transformers is use to, in electronics bench, as a isolation transformer (1:1), we do not connect ground, it must remain in a separate plain, very Andy in to connect oscilloscope to boards, no ground loop. :) cheers.
I admire your standards of workmanship, James. BTW, I have a similar drive motor that has the annoying property of traveling at different speeds, with the same setting, depending on direction. I’d sure like to improve that. (I think Quinn mentioned it in a past video) Have you seen this?
Question, I have a 5KW 230v inverter charge controller 48v , what’s you’re thought’s me using a 100A MTO Transformer 220-440 inlet & 110-120 output for a house inverter for emergency use only my battery banks are lithium phosphate 3.2v 280Ah feeding the inverter ?
Perfect spot to pick up some chips off the floor in the receptacles..... I'd look at one of the exterior outlet cover solutions you can pass cords through just to pop on the box to keep things out of the plugs :P
I was in a situation where our control transformer was not giving us the correct output so what we did was connect out x2 to the panel neutral and then we bonded it to ground
I really only have one issue with the way you had done this. You left the possibility of plugging in other devices at the same time as the power feed motor. I personally would have used what is called a simplex receptacle connected to the small transformer so only one thing can plug into it. This way you do not possibly overload the transformer and have to replace fuses. What you did is fine and obviously works, it is just that this is on the internet and I have to point out that I would have done it differently. You did do a fine job, as usual, to keep the installation nice and clean.
I guess this is a stupid question, but why not just plug in an extension cord to a 110v outlet, and run your 110v accessories off that? The only reason I can imagine is wanting the 110v circuit to be coupled to the 240v circuit so the 110v drops if you lose 240v, but wouldn’t a magnetic relay take care of that?
I’m no electrician by any means I know jack about it but am I nuts to think that now that box is live to ground when you run anything 110 from that outlet?
Thumbs up. I'm wondering if it could go easier if you had mounted the transformer on the "lid" panel, wired it up and then covered the works with the box 🤔
So what kind of power consumption does a transformation like this use when idle? I assume it will be lower without a load on it and increase as the load increases. But there will always be energy or current flowing on the primary side by the nature of how it work. Ot was thus explained in the video and I misses it somewhere?
In _theory_ an idle transformer that is correctly rated draws no power of it's own. In actuality it generates some small amount of heat and sound energy, so is consuming power. I'd guess that a transformer this size is probably using less than 5 watts, probably 2 watts or less.
They add 4", putting it at about the right height for me to use comfortably. It's just two pieces of 4x6x3/8"-wall rectangular tube with holes drilled in it to anxhor the mill and to mount the feet.
Great video . Did your power supply wire have a neutral and ground from your building ? If so don’t you just have to bond/ground the transformer base only because it’s tied to the neutral back at the panel ?
20:00 did i get this right? there is no mechanical difference in the 120 and 240 Volt outlets as mechanical coding so you can accidently plug in to the wrong outlet?
No. The 120V outlets are NEMA 5-20 and have a vertical hot blade. The 240V outlets are NEMA 6-20 and have a horizontal hot blade. They aren't physically compatible.
I don't know how much digging around you had to do to source all the parts, but boxes, control transformers, and at least some of the wiring bits are easily available form Automation Direct, and they often have 2 day shipping. The prices are reasonable too, and you know you are getting genuine stuff. I'm a little concerned about plugs on the floor. In my experience that is where they get wet, oily, and full of chips swept up or blown around on the floor.
It's been a while since I've done any transformer supplies but since transformers are primarily inductive devices they wont have in-rush current. it's typically the load on the output that cause the in-rush current. There maybe a very small amount of current from capacitive coupling but I'd expect it to be very,, very low.
The Internet disagrees. en.m.wikipedia.org/wiki/Inrush_current "When a transformer is first energized, a transient current up to 10 to 15 times larger than the rated transformer current can flow for several cycles. Toroidal transformers, using less copper for the same power handling, can have up to 60 times inrush to running current."
I've always been very suspicious of those. They come with copious warnings to only use them with hair dryers and not anything electronic. I assume (but don't know for sure) that they're doing something unsavory, like using a diode to cut the total power (but not the voltage).
Im going to build a mill and I'm converting a radial arm saw the motor is no good it only runs at 5000 rpm so I need to replace with a motor that I can control the rpm but I'm not shut what type I need either a stepper or what? could you give me some help with that and where I might be able to get it from?
Good tip. I just re-checked the circuit diagram, and I don't think this one has a multi-tap transformer in it. In fact, the manual actually calls for an external control transformer for operating on high-voltage mills.
Big fan of your channel. The input wiring to your control power transformer primary are both ungrounded conductors so you should avoid using a white insulated conductor because this is always assigned to grounded conductors (neutral) in North America. I dont exactly know what is powering this box but since you have explained that both transformer primary conductors are being fused, I can infer that they are assumed to be ungrounded. I would recommend just adding some red electrical tape or heatshrink at all termination points for that white insulator (on the primary circuit) to denote that this is indeed an ungrounded conductor (L1 - black, L2 - red).
@@Clough42 Not black - incorrect; white should be marked red in this instance. The NEC requires the white (neutral) wire to be marked (tape, heat shrink, whatever) on both ends and at any junctions with usually red, but never black because there already is a black wire for the other 120V phase). Black would indicate both were the same phase at the same potential. If you check the NFPA 70 Handbook you will see you have created what is known as a "separately derived system" for the 120V feed.
@@jpcallan97225 I think that's true for 3-phase, but for single phase 220V, coloring the white wire black is common practice. I have several circuits like this in my house installed and inspected during construction.
@@Clough42 Thank you for the reply. That would be true if the other wire in a 240V single phase trio were red, white and green/bare, but as an example 12-2 NM-B (Romex) is almost always black, white and bare, while 12-3 NM-B is black, red, white and bare, but never two blacks, white and bare. What you are seeing in your home wiring is a switched lighting circuit where white is used as a "traveler" instead of a neutral. The whole idea is preventing an unintended 240V short. The color code is key to avoiding an unintended phase-to-phase interconnect. I'm retired now, but I did electrical designs for small to medium sized data centers with three phase UPS systems and diesel generators as part of my IBM mainframe consulting practice. I have a 60 KW Cummins model DGCB genset and automatic transfer switch at my house. I'm fairly familiar with things electrical. I'd like to speak with you on the phone about your video on the phase converter if that would be possible. I do enjoy your videos and learn a lot from them.
Dear jsmes I've been ordered ELS through ebay.... Like to know how to set with my own Lathe Machine... Can you please help me out to install the software....?
Must be a pretty fancy transformer if you're able to drive a motor with it... Seems way cheaper to just add the neutral on the plug. That's what I did when I tried my 1960s lathe.
I meant you should have tossed a neutral in the run when you put it in. Would have been heaps cheaper than a transformer, extra deep nema box, and the time. But I do enjoy watching you methodically workout this kinda stuff. And I found the VFD vids especially helpful so thanks!
For me, that would not be a joke. It would be funny because it's true. And also because it's an conscious choice, not an impulse. Nowadays, at least. Or so I tell myself...
I am not sure that I have ever run a neutral for 240 split phase that I did not eventually use. Watching you use that crimper raised the hair on the back of my neck. It looks like it would crimp a finger just fine. Despite being disallowed in many applications, I would tin the stranded wire. For permanent installations, I sometimes use a soldered wire-nut connection.
Definitely don't tin the wire before crimping. The crimp terminal is designed to compress and retain stranded wire. If you tin first, the solder will slowly flow over time and the crimp will become loose. When this happens, the joint will heat, softening the solder further, until it fails catastrophically. I've had it happen on a 3D printer. The other problem is that soldered connections do not handle vibration well. The solder ends at some point in the wire, and all of the stress gets concentrated there. Over time, the wires crack and break. This is why you don't see solder terminals in automotive applications.
@@Clough42 , True, but the question remains, did you ask a certified electrician? Not a suggestion that anything was wrong, or needed NEC certification.
@@BruceNitroxpro So Bruce, only "qualified experts" can do things right. The rest of us are just ignorant fools, that don't recognize the need/brilliance of "qualified experts". I bet you like Anthony Fauci.
Transformers high primary/feed sides are identified with the letter X, & the low secondary/load sides are identified by the letter Y. Not sure how you did this. Also: The primary side would have 240V (twice the voltage ... by a SERIES connected across the entire winding. Then the secondary would be stepped down (in half) to 110V by tapping the middle of the winding ... which serves as the neutral to both short 110V windings. You some how made it work by placing the neutral connection to the hot side of just 1 of the secondary windings !!! 🤔
I think you're confused because you're assuming this is a 120/240 to 120/240 transformer. It's a 240/480 to 120/240, so both primaries are connected in parallel (240V), and both secondaries are connected in parallel (120V). I showed the jumpers installed directly on the terminals at around 7:58.
