Canadian wye-delta starting low voltage motors 2

[fab1961]

Dear all,
to start wye-delta an async motor on a 600 volt grid the nameplate should be 575/1000.
I've spent some time over Internet looking for Canadian motor manufacturers but the catalogs
I've found say only 575. How do they start their motors there? Reason I ask is that our subcontractor
is delivering 345/600 motors and we are to build the MCC and I don't know whether I can ask
them to deliver something that does not exist.
Thank you very much for your help.

 

[jraef]

Hmmm... there is something amiss with your understanding of Wye-Delta motors. If you want to connect a motor to a 600V system, it must be a 600V "nominal" rated motor, but the actual MOTOR DESIGN voltage will be 575V. Whether or not the motor is made as Wye or Delta is irrelevant to this situation.

If you want to START a 575V motor using Wye-Delta starting, then your motor must be designed for Wye-Delta starting, irrespective of voltage rating. So that means it must be at LEAST a 6 lead or could be a 12 lead motor. they are two different issues.


" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden

 

[itsmoked]

As Jeff sez. In the big area south of you the typical voltages are 480V but all motors are labeled at 460V as this difference could be expected when the motor current draw is large.

You should also check some threads on the crummy results wye-delta starting can give.
There are many but this one should do: (Note Marke's first post.)
thread237-42958

Keith Cress
kcress -

http://www.flaminsystems.com

 

[roydm]

I live and work in Canada, I have never seen Star Delta starting here, certainly not as part of an MCC

 

[waross]

In North America rated motor voltages are multiples of 115 Volts.
In the US, 115 Volts, 230 Volts, and 460 Volts.
In Canada a standard voltage is 600 Volts and the appropriate motor rating is 575 Volts.
You need a 575 Volt rated motor that is designed for wye:delta starting.
This eill be a six lead motor.
In the US a dual voltage, 230/460 Volt motor for wye delta will be a 12 lead motor.
A 575 Volt, wye:delta motor will be a 6 lead motor.
It should ba no problem having a wye:delta starter installef in an MCC.
Girst find a 575 Volt motor that is suitable for wye:delta starting.
Next, if the MCC builder does not have a suitable starter in their product lineup then find a suitable other-make starter and specify that it be supplied and installed.
Myself I would prefer a part winding starter.
Don't waste time looking for a 600/1000 Volt motor. Look for 575 Volts, star:delta.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[LionelHutz]

You typically don't find dual rated 575V rated motors. But almost any 6-lead motor that is connected in delta for running at 575V can be wye-delta started.

The only wye-delta starters I see are ones being replaced with soft-starters.

 

[jraef]

Several MCC suppliers have ceased offering Wye-Delta starters in their MCCs because Solid State Soft Starters are now more common. The same is becoming true of RVAT starters for the same reason. It periodically costs money to maintain the UL-845 listings of units in MCCs and if there is little demand for them, they get dropped.

I have not used a Wye-Delta starter for anything new in probably 20 years now, it's just not worth it to my thinking. Nearly every one I have seen in the field has problems and I'd venture to say that 90% of electricians don't fully understand them, so they end up messing something up and destroying the starter components, the motor, or both.


" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden

 

[GroovyGuy]

Hey Fab,
By the time you spend $$ on a special motor, special starter & additional motor feeder, why not simple install a solid-state soft-starter?
BTW, what size of motor (ie hp) ae we talking about here? What is the application?
GG

"I have not failed. I've just found 10,000 ways that won't work." Thomas Alva Edison (1847-1931)

 

[fab1961]

Thank you everybody for advice - I owe you some more details: I wrote MCC to cut a long story short,in fact we are an European company and it happens to us to make electric panels not only for our machines but also for machines we purchase to deliver turn-key solutions - in this case the load are no.4 18.5 kW turbines of a shotblasting machine.
Thanks Waross and Lionelhutz: in Europe motor plates are 400Y/690D, that's why I thought of something like 575/1000.
I think if the motors are not yet bought/installed we could install a three-phase transformer to step down voltage to 460 and either have US-style motors wound to run wye-delta with delta 460 or install a softstarter (in Europe you don't find equipment easily over 480V )
GroovyGuy, jraef: I have already used Siemens sofstarters for the same application for a Customer in UK but, since I was not sure of the load demand I've used one size bigger to make sure we don't get stuck: I have to take some measurements next time !!

 

[zlatkodo]

You can use any 6 leads , delta connected motor for 575 V.

AC Windings

 

[jraef]

Are you sure you need reduced voltage starting for motors that small? In most of the areas in Canada I have worked at, RV starting was not required until you got over 50HP (37.5kW).


" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden

 

[Skogsgurra]

We try to avoid Y/D - it does no good in most cases and creates Heavy peak current when switching from Wye to Delta. See lower right corner of this motor current recording.

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[itsmoked]

Hey Gunnar what instrument is that from?

Keith Cress
kcress -

http://www.flaminsystems.com

 

[Skogsgurra]

I am not allowed to tell. I nearly got expelled (Homer Simpson would have been proud of me) last time I forgot to erase identity.

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[waross]

The typical 575 Volt motor will be a three lead motor.
It won't matter if the motor is wye connected or delta connected, the connections will not be accessable.
You may have better results forgetting wye/delta and using another starting method.

Bill
--------------------
"Why not the best?"
Jimmy Carter