Ok, yes the service does have a neutral. I see now on the diagram, just wanted some input before purchasing transformer. ThanksWhat is your service configuration? is it grounded or not? If the service is ungrounded then you need an isolation transformer to get a neutral or grounded service conductor.
If the service is grounded and the voltage correction is for a machine then a 3 phase autotransformer might be the thing you need take 3 hots and the neutral. Neutral does not have a connection to the auto transformer The hots are connected to the correct input output taps and the load is connected to teh auto transformer at the correct voltage tab, the neutral carries through to the load.
I'm sorry, I meant attached is the diagram to the transformer I looking at, not the machine diagram. .. In case this confused anyoneI have zero experience with auto transformers and was wondering if it will suit my application. Attached is the diagram for a Chinese 3 phase 380-volt machine that requires a neutral. I couldn't source a delta/wye transformer, all my supplier could come up with is this. Please help
Haha! No doubt, I'm just just the poor schmuck stuck with the task of getting it powered up. Here's the nameplate, they just sent it to me. This is a print inspection machine, it supposedly first of its class in the printing world. Tomorrow I will be face to face with the machine and report back before I proceed with ordering any transformer. I do know or has motors and an Arsenal of high powered cameras.Depending on the machine, you might be worse off getting that transformer. If it is just an electric motor, the machine is likely designed for 380V 50HZ, you will be giving it 380V 60Hz if you use a transformer, that will over heat the motor AND make it run fast.
AC motor design is a factor of the ratio of volts and hertz, usually within a +-10% range. A motor designed for 380V 50Hz is therefore looking for 380/50 = 7.6 V/Hz. If you use that transformer, you will be giving it 380V 60Hz, so the ratio will be 6.33 V/Hz, which is beyond the 10% range. The motor will have about 80% of it's design torque, 70% of it's peak torque (used for re-accelerating loads) and it will spin 20% faster. The slip will be higher, it will draw more current while doing less work. In short, it will burn up.
If you just go ahead and apply 480V 60Hz power to it, it will still run 20% faster, but the ratio will be 8.0 V/Hz, well within the tolerance range for the motor (+5%).
If there are other things on the machine that need 220V single phase power, open it up and separate those from the 380V motors and get a separate single phase off-the-shelf 480-240V transformer. Then hope the frequency difference is OK for those things.
Better yet, don't buy cheap crap machinery from China that was not designed to be used here...
Right, my problem is I need a similar transformer for a different machine that's very similar to that one. That transformer is exactly what I need but can't find without resorting to China, which is why I'm trying to source locally.micromind said:If the transformer (8th pic from the top; the one with the gold nameplate) is part of the machine, it can be supplied with 480 3ø no neutral. You'll need to make sure the taps are set for 480, and since the transformer is 3 wire input and 4 wire output, it generates its own neutral.
he could make it inspected and get special inspection from CSA tag (cost over 2000$ though), i see that very often in cnc shop here. China machine cost half the price of other machine :blink:Looks like that VFD will give you the voltage that you want. But that equipment wouldn't fly up here. No CSA or CUL certification.
any transformer shop should be able to make this, they make custom transformer exactly to your voltage needed.Right, my problem is I need a similar transformer for a different machine that's very similar to that one. That transformer is exactly what I need but can't find without resorting to China, which is why I'm trying to source locally.
Yea we had to get quite a few motors/vfds/mccs done that way once.oliquir said:he could make it inspected and get special inspection from CSA tag (cost over 2000$ though), i see that very often in cnc shop here. China machine cost half the price of other machine :blink: