3 phase wiring, star or delta?

[Birster]

Hi

 

At our distillery, we are running on line-to-line 600v. All of our pumps, agitator motors and elements have been wired in star. Elements are 10KW and pumps and agitators are between 1hp to 2hp depending on the vessel. Would it have been better to wire them in delta or not? Our electrician didn't seem to know. Everything works fine as it is, but if anyone can give the pros and cons, that'd be appreciated.

 

Thank you in advance,

[PeteB]

I would like to be educated. I understand 3 phase in Australia but the USA system is more complex. From what I know your regular voltage line to line as you call it (phase to phase I call it ) is 210 V or 120 v phase to neutral. You also might have access to line to line in some places of 480 Volts and the line to neutral will be 277 V.  STAR wiring gives you the lower voltage DELTA gives higher voltage. Check the voltage on the plate of the appliance. 

I can't find any information about 600 Volts, it may be a special transformer fitted for a previous industry at your site.

DO NOT USE ANY OF MY INFORMATION ABOVE without consulting with a licensed electrical contractor

[Birster]

You are right, in the USA, 600v is not common at all. Though, We are located in Quebec Canada, where 600v is commonly available. All of our elements, pumps and agitator motors are currently wired in star except no neutral, only 3 wires. I obviously don't really understand all of it, but hey, you learn everyday.

 

here is the motor from our rotary pump for example:

[PeteB]

Apologies, I didn't know you were in Canada. Thanks for the 600V info, I didn't know it existed.

That motor appears to be a single voltage otherwise it would have 2 different HP ratings. Delta produces more HP than Star. I don't understand 2 POLE, some motors have more. That might be why it can only be wired Star.

All the 3 phase heating elements I have seen have 3 separate elements and can be wired star or delta. Delta gets you way more heat but if the individual elements are only designed for Star = 346V in your situation, they won't last long if you wire them Delta = 600 V The voltage should be stamped on them somewhere.

Conversely if your 10Kw elements are wired Star but are stamped 600V they will heat up much slower. I have come across that mistake 3 times in the last few years.

(I am not a qualified electrical engineer, I just learn stuff because I have been around the block quite a few times, might retire one day but what would I do?)

[starcat]

With typical dual voltage motors, you do not necessarily have a choice as to how you connect the field windings and it depends primarily on the voltage you want to run.

Heating elements are also designed for a specific " applied " voltage which can be AC or DC. If you power up with half the rated voltage your wattage goes down according to OHMs law equations. If you apply ove voltage to elements they will fail quickly.

[starcat]

Here are some more resources:

https://www.chromalox.com/catalog/resources/technical-information/Electrical-Wiring-Theory-Three-Phase-Equations-Wiring-Diagrams.pdf

 

https://www.chromalox.com/catalog/resources/technical-information/Electrical-Wiring-Theory-Three-Phase-Equations-Wiring-Diagrams.pdf

While I hear 600V is common in Canada, I would not be confortable with this utilization voltage except in a heavy industrial setting and with only very electrically savvy people operating said equipment. This is even the case with some 480V loads as seen in the USA. The problem being both a lack of proper training and the lack of common sense these days which makes things double dangerous at those voltages. I have worked around quite a bit of 480V systems and they are inherently more dangerous than everyday operation of 208-240V. 480 Volts is enough power to sustain an arc, and when things go wrong the fireworks and flashover are much more spectacular. 480V capacitors that are used in HVAC applications can often times hold a dangerous charge that will still be present when the line is disconnected. Those voltages are simply Industrial and need to be approached very carefully and with high respect. This is especially the case in wet environments.

[Birster]

Thanks for your input starcat. We use the 600v because that's what was available on-site. After tweaking everything, I can confirm that everything works as it should. Pumps, mixing motors, heating elements. All is good in the end. Obviously, we take your advice and we are very careful while operating any electrical components in our distillery. 

 

Thanks