Shenhui Dual Tube Setup and Wiring

[Martin James]

I have just received our new laser and am in the setup process.
it is 900 x 1200 dual tubes.


I am running a hardwired 220 "extension" cord from the fuse-box. I am using 12 gauge 4 wire. 2 alternating hots, one current carrying neutral and one ground. Inside the box all neutrals and grounds are bonded to the ground rod stuck into the earth under the service box. Where I live it is against code to use a separate un-bonded ground rod, the ground post on the machine will be connected to the ground through the "extension" cord to the box and through the bus into the existing ground rod.


With 15 feet of 12/4 cord we will lose a couple of feet on each end for the box connections, so 10 or 11 feet. I did not look at a chart but I think that 12 gauge is probably overkill.


I plan on grounding the different parts of the machine with some extra copper wire, case, doors, boxes etc.


(use my info at Your own risk, I really know nothing, except that electricity is dangerous, especially for lawyers)
Here in the US most single phase service boxes have 2 separate alternating 110/120 volt bus bars that accept the 110/120 volt breakers. These bus bars are side by side in the panel with conductor tabs that reach out to each side to accept the breakers. For a 220/240 volt breaker, the factory take what is essentially two 110/120 volt breakers and fastens them together. One half of the breaker hooks up to one leg of the bus bar and the other side of the breaker hooks up to the other side. This set up has power from both alternating cables through the two busbars. Our circuits are 2 hots one common and one ground. In addition to the fastening of the two halves of the breaker together, many breakers have 2 switch levers which are fastened together as well, so when one side trips the connecting bar turns off the other side as well. In general 110 volt systems are cheaper to wire and we only need to use 220/240 volts for big loads like ovens, heaters, kilns, large motors, welders etc.


Now I usually over kill on every job, and the wiring on this Shenhui has me a bit perplexed. They have sent me two IEC-320 Style computer monitor cords. I think they are .75mm, which is not very HD.


I plan to run shop air through a desiccant dryer using a separate existing circuit. The chiller is the CW5200, that is the same as cw5000 but for dual tubes. I plan on hooking that up to the switched outlet on the side of the machine.


It is a dual tube system but the only one tube will be used at a time. Eventually I might hook up a solenoid to the air.


Here are my questions


1) Are the IEC 320 cords big enough for the setup?? Or is it silly to use a $2 cord. (can you even buy this cord in thicker gauge?)


2) Is there a consensus on how big the wires on a 150 watt tube should be.


3) Can my computer be ruined by hooking it to the USB


4) Inside the laser one of the boxes has a 110/220 volt selector switch, the switch is set to 110, I ordered 220. Is there an easy way to know if my machine has been built for 110 volt service? Or part 110 part 220?


Thanks for the help, Marty

[Kev Williams]

I just went thru this scenario back in December...

If you ordered your machine from China with 220 volt service, it's likely wired for "European" 220, which means you can't connect it to an "American" circuit box. As you pointed out, our 220 comes from two 110v lines. Their 220 comes from ONE 220v line. Their 220v service is exactly like our 110v service: One hot, one neutral, one ground. They just put all 220 volts on ONE line.

To make your machine work, you may need to buy a step-up voltage transformer. My Triumph, the blower, chiller and air pump are all Euro-220v, and I bought a 3500 watt transformer. Mine is under the arrow in the pic below. It runs everything just fine...

[Martin James]

Thanks Kev. I have been reading as many posts as I can find on Shenhui/China + electric.
How much did your step up transformer cost?
How did you come up with the 3500 watts?
Is that transformer plugged in to a regular North American 110/120 volt 3 prong 20 amp circuit?
Does it automatically set the voltage? etc.
My Laser has 2 IEC-320 electric inputs.

I went back and reread your post. http://www.sawmillcreek.org/showthre...39#post2186339

Thanks Marty

[Kev Williams]

First off, I goofed, it's a 3000 watt xformer-- I think I paid $165 for it online. I came up with the amperage by assuming the MOST the laser would use is 1000w, and I'm pretty sure it's much less than that, the blower is the power hog at 500w, and I added another 500w to start it. The chiller isn't refrigerated so it may use all of 150w, and same for the little blower. That's 2300w worst case (as I see it) so I figured 3000w should be plenty. The only thing that budges the power meter on the xformer is the blower. No matter what the laser, chiller or blower does, the xformer doesn't act like they're there. IIRC the 4000w xformer was only about $20 more. It has a weird plug, that plugs into an adapter that plugs into a plain old 110v light socket. I assume you can get different adapters for high er amp inputs. I have a 110v socket screwed to the electric box, wired to a 20amp breaker with all of 8" of 8 gauge copper wire. I check the plugs and wires all the time, they're never warm, and no hot spots on any of the plug terminals. Grounding is a bit weird, the xformer has 2 110v outs and 2 220v outs. But the 220's are just 2 wire, hot and neutral. No ground. I have my machine grounded at the breaker box.

[Bill George]

Before I spent any money on transformers, I'd gain access to both power supplies and read the nameplates. My guess they are dual volt 220/110 like most computer supplies. Slip the switch over to 110 and plug in your cords to your normal 120 volt outlet. I bet it will work just fine.

Since the AC motors I have worked on (in the past 50 years) don't really care if its a "hot" wire and "neutral" in fact you can switch them around without changing anything inside the motor at all. Its just looking for either the 120 volt or 240 volt across the two input wires. In this case you've already got the 240 volt line at the machine. Quick way to find out, take the motor leads with a ohm meter and read to ground, my guess unless your reading the resistance of your fingers holding the leads to the wires, both will read very high resistance, like meg ohms.

[George M. Perzel]

Martin;
I have a dual tube 80 watt Shenhui which was factory wired for Chinese 220v, even after requesting 110. No big deal. They "solved" the problem by including a separate 110 to 220 transformer which weighs a ton and occupies a shelf in the basement and is awaiting a future application-probably a boat anchor.
The bottom line is you don't need a transformer if you have the US standard electric service as you described. Run a 220 powerline from your mains and terminate in a standard 220V outlet )(110/110/Neutral/Gnd). Then make a power cable to connect the outlet to the laser 220V input. Install a Ground stud in the rear of the laser and run a ground wire (#10) to either a ground rod or to the house ground in the house power panel.
Then go thru the laser and make sure all the laser metal frame structures are grounded together, grind off the paint if necessary to get to bare metal. Also ground the power supply chassis (both) and the water flow sensor. I also recommend a commercial 220V surge protector betweeen the laser and the power outlet. Attached is a schematic which may help. Email me for a power wiring diagram which is too big to upload here.
Best Regards,
George
gmperzel@rochester.rr.com
Laserartsdiagram for big machine.jpg

[Bill George]

So the power supplies are like the 220 V motor they don't care if its a neutral or a hot, just as long as it sees the 220 across the inputs?

Makes sense because sometimes the neutral, usually in older buildings is not really the grounded conductor. Not on purpose, but because sometimes things get changed or just not done right.
Sometimes however, on overseas made machinery green is not always the grounding conductor for the machine. When In doubt a ohm meter can save the day.

[Martin James]

Like this for the surge Protector? The IEC-320 cords would fit. This one is 220 volt with 330 joules, the cheaper 120 volt has 3300 joules. Thanks Marty

trip lite 220.jpg

[Martin James]

And here are some picts. Should the leads on a 150 tube be bigger than on a 60?
Cheers Marty
Dual tube 3.jpgDual tube 5.jpgdual tube 6.jpgDual Tube 4.jpg

Shenhui Dual 2.jpgShenhui Dual 1.jpg

[Rich Harman]

Wires are sized for current carrying ability. The amount of current going to the tube is tiny but the voltage is very high. There is no problem with those wires. Those IEC cords are fine for the amount of power the laser uses - and running at 220V vs 110V, they can carry twice the amount of power. It is more efficient to send power through wires at higher voltages - less loss due to resistance, that is why transmission lines operate at hundreds of thousands of Volts.

We get 110V on two bus bars because the mains transformer is center tapped. When we wire from one hot to neutral we get 110, when we wire across two hots we get 220V. Wiring across the two hots is the same as if there were no center tap. The attached image shows how wiring from either hot to neutral (ground) gives you 110V and hot to hot gives 220V.

I put in a 220V circuit just for the laser and wired it so that the two prongs of the IEC cord go to the two hots and the ground goes to ground. I also made sure that the power supplies were switched to the 220V setting. I don't remember but it may be that the ground prong on the laser side wasn't connected to anything anyway. I do have the laser grounded using a copper ground rod.

Your IEC sockets look like they are wired such that one hot would need to go to the "ground" pin (don't actually do that though). I don't recall if mine came that way or not. If it did, I probably changed it. I will be back home tomorrow evening. I can check and see what I did, then get back to you.


power-transformer-wiring.gif

[Bill George]

I would strongly caution anyone who is going to take a standard US 120 volt outlet and wire it for 240 volts. As taking the blade connections and wiring each side of a 240 volt circuit to them instead of the standard 120 volt hot and 120 volt neutral. Someday someone will plug a standard 120 volt appliance into that socket and bingo now watch that magic smoke escape! The round or U shaped plug should never be used for a hot wire, only for a grounding conductor for equipment ground.

Have I seen the above done, Yes almost burnt up a $300 wattmeter I was using, customer says" we all just know that's the 240 volt outlet!"

[Rich Harman]

I would strongly caution anyone who is going to take a standard US 120 volt outlet and wire it for 240 volts. As taking the blade connections and wiring each side of a 240 volt circuit to them instead of the standard 120 volt hot and 120 volt neutral. Someday someone will plug a standard 120 volt appliance into that socket and bingo now watch that magic smoke escape! The round or U shaped plug should never be used for a hot wire, only for a grounding conductor for equipment ground.

Agreed. I used 220V outlets and replaced the ends of my IEC cords with 220V style plugs.

[Martin James]

Your IEC sockets look like they are wired such that....

Hi Rich, thanks for the help.

Those are the ICE-320 with the fuse inside the receptacle, thats why the red wire comes off the bottom because it is wired through the fuse holder. That put me off too, as I studied the picture. I had to go back and stick my head in there to see all the wires and understand why they do not come straight off the pin holes.

Thanks again, I am reading up on this. Your center tap picture helps.

I hit on a page that said the wave is 240 up + 240 down but the common is 120 up + 120 down so the load device sees the difference as 120 + 120 = 240 volts. They had a picture i will try to find it again.

[Rich Harman]

I hit on a page that said the wave is 240 up + 240 down but the common is 120 up + 120 down so the load device sees the difference as 120 + 120 = 240 volts. They had a picture i will try to find it again.

110V AC is the RMS (root mean square) value. The RMS value is about .707 * the peak voltage. Since AC current follows a sine wave it would not be meaningful to call it by it's peak voltage. The RMS value equates it to a DC voltage that would supply an equal amount of power. So regular 110V household power has a peak voltage of about 155V and a peak to peak voltage of about 310V.

But none of that is important right now, don't let it confuse you. The peak voltages and peak to peak voltages are not useful for what we are talking about. The load device "sees" an average of the peak to peak voltages and we call that either 110V or 220V.

[Rich Harman]

Those are the ICE-320 with the fuse inside the receptacle, thats why the red wire comes off the bottom because it is wired through the fuse holder. That put me off too, as I studied the picture. I had to go back and stick my head in there to see all the wires and understand why they do not come straight off the pin holes.

What concerns me is that there are only two wires - one of them, the center pin, is grounded to the chassis. You don't want to wire something up with two hots as it is now because one of them will electrify the chassis.