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View Full Version : Appropriate 110-220 step up converter for 100 w laser



daniel coyle
08-22-2014, 1:55 PM
Hi all. My 220V 100W chinese machine was running well and then cut out on me mid stream by flipping the circuit in the main panel in the shop. I pulled all of the accessory pieces off the line (220 water pump, fan, air pump etc.) and it still would trip the circuit.
confused and guessing that the PS was defective I ended up (and there is a longer story here) sending the PS and transfer board back to china for repair. Just got them back (they said they both DID need repair) put them in and the same thing happened!!!! This time I pulled the laser off the line though and put the accessories on individually, testing them one by one, and found they would trip the circuit as well, if not immediately, then with only a few seconds of operation.

I am assuming after all this time and money that it is most likely the 1500W step up power converter that is the culprit. So

any thoughts generally?
any recommendations for a good converter to replace this one with (power and brand)?

Thanks

Dan C

Bill George
08-22-2014, 2:00 PM
Do you have 230 volt available? If so do a search, we just went through the whole conversion thing about 3 months ago.

Mike Audleman
08-22-2014, 2:40 PM
Breakers go bad. Have you tried swapping out the breaker? Its a cheap thing to try.

Can you go across two 110 legs (opposite phases) and get 220 using a double breaker?

daniel coyle
08-22-2014, 3:44 PM
Breakers go bad. Have you tried swapping out the breaker? Its a cheap thing to try.

Can you go across two 110 legs (opposite phases) and get 220 using a double breaker?

I guess i will try replacing the breaker. The board was just put in last year. If it aint expensive then... is there a physical way to look at it once its out and diagnose if it is bad or do i just need to swap it?

AND, do you know anything about step up converters and whether this was the right one to buy?

Bill George
08-22-2014, 4:18 PM
My guess is your present step up transformer is bad or hooked up wrong. PS see my signature, I used to do electrical plus a lot of other things.

I really doubt a printed circuit board would pop a breaker, smoke a lot and burn but not trip a breaker.

If you have 230 volt available and most people do, the convertor or step up transformer is not needed. Just wire 230 volt to the laser supply, with the proper electrical hook ups.

Mike Audleman
08-22-2014, 4:35 PM
Is your equipment 1, 2 or 3 phase 220/240? If its single phase, I am unclear why you are using a 120>240 converter unless you just didn't want to run 220 to that equipment bay?

Common 120/240 service consists of two opposite phases of 120 with a neutral between. So, from Neutral to Phase 1 is 120 and Neutral to Phase 2 is 120. They are 180 degrees out of sync so by going from Phase 1 to Phase 2 you get 240, no neutral. It totally depends on how your equipment is wired. An isolation transformer may be required if its chassis is tied to one leg of the 220 assuming its a neutral. It should NOT be but its chinese so who knows. Ground is ground either way and is not involved in the 120/240 issue.

Unfortunately the ones I was familiar with in the past are pretty much overkill for you. When I was working as a broadcast engineer we were using 480v 3 phase transformers that were bigger than a Prius and weighed 10x more and were in the multi-kilowatt size. Just a guess, you should be able to locate a 220 to 220 isolation transformer for sub $1k easily. Might even find them in the $500 range.

You should have an electrician look at your equipment to see how its wired. You may not need any transformers at all, simply using bridged 120v phases may do you. Might be worth a shop call to get the facts from an electrician who can tell you exactly what you need based on the equipment and power available at your shop.

In any event, if you are running 240v equipment on 120v lines, just remember that the current will double. So if you are pulling 240v at 10a, the 120v side is seeing at least 120v at 20a (plus loss through the up converter).

1500w is 120v @ 12.5a (P=I*E or I=P/E). Who knows the loss going through the converter. If its say 90% efficient, then 1650w is drawn at 13.75a on the 120v side. If this is plugged into a typical outlet, thats likely 15a. Thats really close to your 1500w. Spikes could be tripping the breaker as the equipment is powering up.

I would also look at the possibility of other things on the same breaker as is feeding your 120v>240v step up. If you have added anything else to that breaker line (say a fan or work light), it adds to the breaker limit. So check around and make sure other equipment isn't drawing from the same breaker. I mean, what else goes out when the breaker pops? Total all the equipment;s amps up and it has to be less than the breaker's rating.

daniel coyle
08-22-2014, 7:17 PM
Thanks. I DO have 220 that I can run to this. I have limited 220 in the shop (it is dedicated to other things) but I will try to re-wire the chinese plug to fit one of these lines. At this point that makes sense IF I can do this through a typical power strip (YES??)
All of my accesories are plugged into a power strip right now that is supplied by the step up converter. Should I be able to use this same power strip with a 220 set up?

Bill George
08-22-2014, 7:29 PM
Thanks. I DO have 220 that I can run to this. I have limited 220 in the shop (it is dedicated to other things) but I will try to re-wire the chinese plug to fit one of these lines. At this point that makes sense IF I can do this through a typical power strip (YES??)

All of my accesories are plugged into a power strip right now that is supplied by the step up converter. Should I be able to use this same power strip with a 220 set up? NO you will need to install some switched outlets rated at 230 volts because the power strip has standard 120 volt rated outlets.
Once again please do a search on this, we just had 3 pages about running a Chinese 220 volt machine on US 220 volts a few months ago.

OK Here you go.... > http://www.sawmillcreek.org/showthread.php?219692-220-volt-issues&highlight=230+volt

Dan Hintz
08-22-2014, 8:32 PM
Is the converter rated for 1500W continuous, or is that the max (i.e., burst)? It's best to de-rate converters by a good 20-25% for continuous runs if it's not rated for that... in your case, that converter is only good for 1200W of continuous power. My 80W machine needs a 20A@120V line... I haven't measured, but I bet the machine itself is sinking 2000W. And that's an RF tube, which is more efficient than your DC tube.

My verdict? You're simply asking entirely too much from your converter and it finally gave up the ghost, taking equipment with it.

Kev Williams
08-22-2014, 11:15 PM
I'm the source of Bill's link above, and just did the 220 changeover. Should've done it in the first place...

Frankly, I'm surprised you could even run your setup on a 1500w transformer, I can almost guarantee it's the source of your blown breakers. I used a 3000w unit and it only lasted 6 months.

Anyway- changing over is a piece of cake. The first thing to get clear in your head is there will be no neutral wire. Second, you must use a 220v breaker to insure you're using out-of-phase hots. Third, make sure grounds are done right.

Because all of my Chinese equipment's plugs look identical to, and will plug into every 110 volt plug in my house (I'm sure yours are the same), for "convenience" I just rewired the 110v outlet that used to run my transformer. To do this, first I disconnected the outlet's white neutral wire from the breaker box neutral bus bar, then removed the outlet's black hot wire from the 110v breaker it was connected to. I already had an unused 20amp 220v breaker installed in the box. So then I connected the black hot to one side of the 220v breaker, and the white "what-used-to-be" neutral wire to the other side of the 220v breaker.

That's it. Done.

I plugged the air pump into the outlet, and it ran fine. Followed by the blower, chiller, and finally the laser.


When I got my machine, to switch on the accessories I rigged up a plastic 3-gang switch box and screwed it to a piece of 2x8, which sitting on top of my machine on the right side, within arms reach. I installed 3 light switch-over-outlets like this:
295425
--the outlets are fed from length of 12/2 wire with an outlet plug on the end, which was plugged into one of the transformer outlets. The laser was plugged into the second transformer outlet.

My switch-outlet receptacle plug is now plugged into the bottom of the new 220v outlet. The laser is plugged into the top outlet. The chiller is plugged into one of the laser's accessory outlets (didn't need the 3rd outlet switch since I can reach its on/off switch easy enough).

NOW, I REALLY SHOULD CHANGE OUT THE 110 VOLT OUTLETS TO TRUE 220 VOLT OUTLETS! So that 110v stuff can't be plugged into them. And I will change them, soon. But I'm the only one who uses these outlets, they're marked as 220, and everyone who might try to plug into them knows they're 220. :)

Like I said, I wish I'd done it sooner...

Bill George
08-23-2014, 8:28 AM
Frankly the FDA should stop worrying about inspection when they come in customs and turn the job over to electrical inspectors. There is No way any of these machines meet NEC requirement and most cities and states that is Code for wiring.

Mike Audleman
08-23-2014, 4:10 PM
Frankly the FDA should stop worrying about inspection when they come in customs and turn the job over to electrical inspectors. There is No way any of these machines meet NEC requirement and most cities and states that is Code for wiring.

Well, mine didn't. Heck, it didn't even have a breaker when I got it! A hole for one, but none installed. I remided that with a quick order from mouser.

Bill George
08-23-2014, 5:47 PM
Well, mine didn't. Heck, it didn't even have a breaker when I got it! A hole for one, but none installed. I remided that with a quick order from mouser.

Mike the machines are considered protected by the branch circuit or in the case of a dedicated circuit its fuse or circuit breaker. Nothing to say you can't add anything you want to the machine however. I guess I was thinking about the 120 volt outlets on the machines that are wired for 240 volt volts.

Mike Audleman
08-27-2014, 4:29 PM
Mike the machines are considered protected by the branch circuit or in the case of a dedicated circuit its fuse or circuit breaker. Nothing to say you can't add anything you want to the machine however. I guess I was thinking about the 120 volt outlets on the machines that are wired for 240 volt volts.

The line in went directly to the emergency shut down switch. There was a hole in the cabinet where a fuse should be. I de-soldered the hot lead from the back of the power in jack, added a panel mounted 15a breaker, jumpered from the power in jack to the breaker and and attached the former main lead to the breaker. So, if anything goes wrong in the cabinet or with any of the peripherals (pumps), the local breaker will pop. I am running this on a 20a circuit so the local breaker will pop 5a before the wiring breaker will.

I did this since its not just the laser cutter, its the pumps as well being fed by a single power cord. I looked at the laser cutter as being a power strip. One plug from the wall feeding multiple devices should have a local breaker (like virtually all outlet strips do).