Integrating Wye-Delta in control panel

[Thomas Sullens]

Good question.

Mostly because it was specified.. it matches their other equip.etc.

Secondly, at 500hp I'm guessing W-D is significantly cheaper.

W-D is probably not going to be cheaper and something else to consider is wire size. Is it specified too? The reason I`m bring this up is two years ago we changed out a auto transformer starter to a solid state it was on a 500 hp 480 volt motor the starter wasn`t the problem. The problem was it had 3 - 500 mcm`s per phase and there is no way I would put a plc in this enclosure if it would fit. Ask the Engineer if he wants to be the one to trouble shoot it ? Use NEMA if you want it to last.
Good Luck banghead

 

[JesperMP]

I would NOT attempt to build a wye delta start system

Why not ?
We build Y-D starters into our panels. For smaller motors we use softstarters, but for larger motors Y-D starters are still more cost effective. Also, even with a softstarter we normally install a bypass contactor, otherwise there will be extra losses with the softstarter. And these losses has to be paid for over the lifetime of the application. With a bypass contactor the softstarter is clearly more expensive than a Y-D starter.

Cannot say anything about the NEMA/IEC issue. Over here we only have IEC contactors. But it is also quite common to go one size up.

 

[jimpad]

Thanks guys,

I'll look at the IT, Benshaw, etc.

Elevmike that's an interesting idea. Do you bring up the points about motor cost etc. because the wear and tear is more with the WD vs solid state?

I'm puzzled about the enclosure size. The size 6 starter enclosures I've seen from the OEM have been about 54" high X 10" deep X 32" wide. They were tight but they fit along with all aux's.

Anyway, last I heard from the customer he wasn't sure if the motor he'll be using is wired for WD so maybe just a bunch of hoops for nothing.

Jim

 

[JesperMP]

he wasn't sure if the motor he'll be using is wired for WD

Believe me, a 500 HP motor can be connected in Y-D (unless it is very special).
For it to be possible to connect in Y-D the ends of all three phase windings has to be accessible. In other words: there has to be 6 taps to connect to.
And there will be if it is a "regular" 3-phase asyncronus motor.

 

[twbtxnca]

If it is not wired for W-D it is older than me and I am older than dirt. I would'nt want to pay the demand charge from the power company on starting that jewel.

Regards,
Tom

 

[rsdoran]

A 500HP at 4160vac wouldnt necessarily need Y-D start. If its running at 480vac then it will more than likely need to use Y-D start. If its above 600vac then I would NOT put my plc in the same panel under any conditions.

Its possible to configure one panel to include everything but its not always the best approach.

I believe at this point you need to determine ALL the details of the project.
1. Y-D start? What voltage?
2. Speciified brand or type of starter?
3. Can a SoftStart be implemented?
The list goes on but its hard to give specific information when the all the details are not known.

 

[Old Timer]

Hello again (I used to have an account but lost details).

I have my C-H "IT" literature out.

Application: 500 HP squirrel cage motor, 460 VAC, 1.15 Service Factor. 25-second ramp, 4 starts per hour, 300% current limit @ 40 Deg C ambient. The C-H IT is the model S801V72N3S.

Dimensions 280 W x 420 H x 195 D (mm) / 9.1 W x 16.6 H x 7.7 D (in.) 41.5 Kg / 91.3 lbs. Also requires a little panel space for a 24VDC power supply.

That is a lot smaller than most supplier's softstarts, and it includes internal bypass contactors. A fraction the size of a wye-delta starter or an autotransformer starter with same starting capability.

Note, a reduced voltage autotransformer (RVAT) starter probably cannot do more starts/hour due to heating of the autoxformer coils.

I am extra concerned about space, since many of my applications are mobile. Of course, if the customer insists on wye-delta, that is what should be supplied. But a good exercise is to explore alternatives.

Al

 

[jimpad]

Old Timer,

That's a nice looking unit. What did it cost you?

Jim

 

[Tom Jenkins]

I haven't seen many Wye/Delta or autotransformer reduced voltage starters lately. The RVSS (Reduced Voltage Solid State) starters are more economical in the long run (less MCC space, better control, more built in protective features) and are just as reliable. Make sure you get one with a built in bypass contactor.

I really like the Cutler Hammer IT series. The new A-B units are much better in terms of value and form factor than the old SMC's but I haven't had a chance to use them personally yet. I haven't been impressed with the Square D units, but I haven't seen any for a couple of years so maybe they have improved.

 

[JesperMP]

I just had to check the prices for a softstarter w. bypass vs. Y-D starter in the 600A range (500 HP @ 460V). It is interesting sometimes to know rather than think what the truth is.

Hmmm. I get that the Y-D starter is one quarter of the softstarter !
I use Siemens gear (granted it is maybe a bit expensive, but we have a nice discount from them, and I guess that the price ratios are approximately the same if you use other brands).
I didnt get the price of a fixed unit, but rather just got the prices of two large contactors + one small + connections.

So I dont aggree with the assumption that a softstarter is not much more expensive than a Y-D starter.

Edit:
This is in response to TWBTXNCA's price of approx 59.000 USD ! (below)
I think that his price is over the roof !!
The Siemens 3RW2247-0DB16 (rated current 865A at up to 690V) has a list price of approx. 20.000 USD.
A Y-D starter for a similar rating will have a list price of approx. 6.000 USD.
In addition to that we get a VERY substantial discount on the list price.

 

[twbtxnca]

QtyCatalog NumberThis is the list of a AB soft start
Regards,
Tom



Description
Net Ea1152B-B650ABD-61-89F22-NICombination SMC Dialog Plus, IP30 - NEMA Type 1 Enclosure with Isolation Contactor, 650A, 400-480V AC 50/60Hz, NEMA Isolation Contactor, Bulletin 700CF 4-Pole Relay - 2 N.O. and 2 N.C.59011​

 

[twbtxnca]

Didn't get the price in it is $59,011.00 list
Regards,
Tom

 

[rsdoran]

I didnt look at Toms specific unit but several of the SMC with enclosure, disconnect and isolation relay for 500HP are listed over $50000.

A quesion was asked about NEMA and IEC, AB has a page on this:
http://www.ab.com/mcc/1_MCC_Introduction/5_DifferencesBetween_NEMA_IEC_Components/01_05_01.html

I didnt think about this before but AB also makes MCC (Master Control Center) that incoporate plcs etc.
http://www.ab.com/mcc/2_CENTERLINE_MCCs/a1_Overview/02_0a1_01.html

How its done depends on many factors. You will need to talk to your suppliers on what can be obtained and at what price. Once you get the information together on prices, features, dimensions etc then you can make an informed deicision.

You will definitely need to know if its going to be a low voltage (600v or less), or medium voltage. If not using low voltage then you may need transformers or other accessories.

 

[twbtxnca]

The largest I could find on the center one software was 400 hp.
Here it is.
Regards,
Tom

MCC Name:​

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soft start
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Customer Name:​

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plc
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Unit ID:​

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2
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Unit Description:​

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Soft Starter Controllers /SMC - Combination Soft Starter Controller (SMC-Flex)
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Allen-Bradley Catalog:​

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2154JB-F480LKB-4TB-13GD-59-750RL-751HS-90189
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Delivery Program:​

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SC-II
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Line Voltage:​

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480 Volts / 60 Hertz
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Disconnect Type:​

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Fusible Disconnect
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Enclosure Type:​

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1 - General Purpose
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Space Factor:​

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6.0
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Unit Size:​

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480
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Required Section Width:​

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20"
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Wiring...
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B-T Control and Power Terminal Blocks
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Current Rating...
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480A
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Horsepower...
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400 HP
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Control
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Transformer with Secondary Fuse
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Standard Capacity
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Internal Primary Protection
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120V/60Hz
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Control Wiring...
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#16 AWG Cu, Type MTW
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Unit Nameplate
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Cardholder Only
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Options...
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Add Pilot Light : OVERLOAD [FAULT for SMC-3], Type : Standard, Color : Blue
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Add Starter Mounted Auxiliary Contacts : 1 Normally Open, 1 Normally Closed
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Add Disconnect Mounted Auxiliary Contacts : 1 Normally Open, 1 Normally Closed
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0 Normally Open mounted internally, 0 Normally Closed mounted internally
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Add Control Wire Markers : Add Heat Shrink type markers (-751HS)
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Add Control Circuit Ring Lugs (-750RL)
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Add DeviceNet Communication Module Mounted Internally for SMC Flex (-13GD)
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