I have a 2015 Fadal 4020B Taiwan Built 2015 Series 1 VMC with High Torque motor (23 KVa) useing Syntec Spindle Drive from 240 Volt Single Phase 200 amp service (Edison Electric Residential Service) converted to 3 Phase power thru a North America 30 HP Rotary Phase Converter. Because the input is 240 volt vs. 208-220 typically found in commercial buildings my output on the 3rd phase manufactured leg is reading 255 (Phase Converter engineer states higher voltage comes down close to 240 when put under a load...spindle running) at the machine The other two legs are apr. 240. Initially the installation tech was concerned with the 255 volt reading and wanted me to buy an $1,800 step down isolation type transformer which is also quite large and as many know when they are running they make a somewhat annoying buzzing sound. Very small shop in residential neighborhood so space and noise is also a condideration. I contacted both engineering departments from Syntec Spindle Drives and Yaskawa Axis drieved and they say Im at the high end of the +/- 10 % over 230 volt listed in there technical manual. If I dont have to buy a huge transformer I would want to go this direction Anyone out there have experience with my situation?? Thanks in advance..........
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??? 2015 Fadal Taiwan Built 2015 Series1 Syntec Spindle Drive from 240 Volt 3 Phase
- Thread starter Gman4405
- Start date
- Replies 48
- Views 3,780
atex57
Stainless
- Joined
- Sep 6, 2006
- Location
- SW Wisconsin
Two buck transformers is what I bought for a Hitachi lathe with about the same KVA. Get ahold of a motor shop and ask them for recommendations. Cost me about $500 5 years ago.
Ed.
Ed.
The manufactured leg doesn't really matter. it will drop down lower than the other legs under load. 240 is right on the cusp. It will probably work fine, but if you run across a deal on a 30ish KVA 240-208 WYE transformer you should buy it. Check your voltage regularly. If you see it creep over 240, like 241,242, you should not run it like that.
You won't hear the buzzing sound. I have 10+ transformers in my shop. One makes a little noise, but it's from 1979 and had a hard life.
You won't hear the buzzing sound. I have 10+ transformers in my shop. One makes a little noise, but it's from 1979 and had a hard life.
macds
Hot Rolled
- Joined
- Jul 24, 2008
- Location
- Milverton, Ontario, Canada
I use a buck isolation transformer after my RPC since I have some very picky Japanese machines.
Cost, sound, space.... yes.
Having better than grid 3 phase, PRICELESS.
Cost, sound, space.... yes.
Having better than grid 3 phase, PRICELESS.
After reviewing all the information it seems like the on site techs are not basing their experience of actual failures in the field but simply leaning to a safe answer to protect themselves. But when speaking to actual engineers that design and test these drives their experience is saying they build in a tolerance and that I am actually in the safe range.
Thanks for your reply Ed!
Wow!... Better than grid 3 phase? I have never heard thaty clain even by two different RPC engineers. Why do you say its better? Please explain in detail. Your saying your actually useing a single phase transformer before the RPC ? What are your voltages from leg to leg on the output side of the RPC on each leg as follows. L1-L2= L1-L3= L2-L3= Thanks for posting!
Vancbiker
Diamond
- Joined
- Jan 5, 2014
- Location
- Vancouver, WA. USA
Consider the possibility that the onsite techs you talked to don't want any failures or customers having problems so that's why the are giving conservative answers.
My experience is that when your line power is close to, or at max voltage you have more issues and failures than if the supply is close to nominal. I've not worked on a Syntec spindle drive. If it dumps the braking power through an oven element like the old Fadals then you may be OK. If it is a line regeneration style braking dump then you stand a good chance of seeing overvoltage alarms or trouble with the drive or other components of the machine.
Another consideration is that if you toast a spindle or axis drive due to running at or just beyond max voltage you might spend more on a fix than the cost of a couple buck transformers on the RPC input.
BT Fabrication
Titanium
- Joined
- Nov 3, 2019
- Location
- Ontario Canada
easy, pull out one of the Capacitors to drop the voltage on that specific leg.
Bobw
Diamond
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- Feb 8, 2005
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- Hatch, NM Chile capital of the WORLD
Does this "Fadal" have an internal transformer like the old fadals?
Tap her for 250v and go.
Thats what I do, if I tap for 240v I end up with 244v running in the machine,
at 250v, I get 232 to 236 depending on the day.
Tap her for 250v and go.
Thats what I do, if I tap for 240v I end up with 244v running in the machine,
at 250v, I get 232 to 236 depending on the day.
When I researched Transformers i discovered so many types it made my head spin. When talking with the RPC engineer he said if I did decide to go with a tranformer he stated we would not use the cheaper Auto Transformer because it produces "Dirty Power" but recomended to go with the most expensive option a "Isolation transformer" at $1850 as it produces a higher quality output and also is "isolated" protecing the electronics of the Fadal drives. He was suggesting putting it on the "output Side" of the RPC as the converter put out a bit higher voltage on the "manufactured leg" (in my case 255 volts) He stated the isolation transformer would also help balance that out also as I would target a 216 volt output on the "taps" of the transformer. So I guess my understanding from him is that the "Buck" transformer puts out a lesser of a quality of power. May I ask have you seen setups where the buck transformer was a single phase type set up on the "Input voltage" to the RPC? If so what were the voltages in at each single phase leg and what were the reading out of the buck transformer and then out of the RPC on Leg to Leg readings on the three legs of 3 phase power? Thanks for any information you can share.....
No it does not have an internal transformer for the main power.
Can you be more detailed in your response? Keep in mind this is not the older American built Fadal. Totally different electronics
ifixcnc
Hot Rolled
- Joined
- Feb 6, 2015
- Location
- Cleveland Ohio
I think he is talking about the Caps in the RPC?
Hardplates
Stainless
- Joined
- May 8, 2019
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- What once was a free country
Yes you can put a transformer on the single phase side but regardless of where you put it the voltages are going to be dependent on that specific transformer and how it is tapped. Transformers are inductors and can help to smooth out dirty power.
AC run capacitors are used to adjust the voltage of each leg, but it is highly dependent on load so a rotary phase converter with perfect voltages at idle will rarely be well balanced under load.
More inductive loads will help balance out the power but not if they are ran through a drive.
Vancbiker
Diamond
- Joined
- Jan 5, 2014
- Location
- Vancouver, WA. USA
The use of an isolation transformer on the output of the RPC would the best IMO, but also costly. Nice to recommend when spending someone elses money.
Bucking the input to the RPC is less expensive so gets done more often. Since single phase buck type transformers are usually multi-tap you can get a nice range of voltage drop to hit a desired value. I do not have record of specific voltages from RPC powered machines that I have worked on. I'm also no expert on the details of RPC construction or "tuning". My experience comes from trying figure out CNC troubles and sometimes tracing it back to incoming power issues.
This forum has a sub-forum dedicated to the topic of RPCs transformers, etc.
https://www.practicalmachinist.com/vb/transformers-phase-converters-and-vfd/
Probably worth a read through some of threads there.
Im so pleased you are takeing part in my post and shareing your information!
So you seem to feel even thogh the engineering department from Syntec (New Fadal Spindle control) and Yaskawa (Axis drives company) conform that I should be safe according to their specs I still may have troublt in "Real Life" scenario?
Would you happen to know of a good online store I can get these transformers so I can check price and avaiability?
Have you seen any issues with useing a "Single Phase" step down Buck Transformer thru a RPC ? If so what was the symptoms?
Thank you much for your input!
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