Integrating Wye-Delta in control panel

I've been asked to install the main motor wye-delta starter in my plc control panel for a machine. I've seen this setup many times where the starter and controls are in the same panel although I've never done the design on the starter only the plc and logic. previously I've seen Nema size 5 and 6 starters installed. Now, I have to supply the starter.

1. How do I choose between IEC, NEMA? (Does this question even make sense?)

2. Does anyone know where I can find all the components already installed on a backplane for mounting in my panel? So far I've only been able to find the complete starter and enclosure at AllenBradley but that doesn't leave room for the plc and auxilliaries.

3. If I have to build it up myself, does anyone know of a cookbook approach where the basic steps are identified?

Thanks,
Jim

Why Wye-Delta?

My company has just spent $1000s to replace two 125 HP @ 460 VAC wye-delta starters with C-H "IT" soft starts. The C-H IT starters are smaller, have fewer connections and are easy to set up. And they survive in the harsh environment our customers use them in, mobile rock crushers for surface mining.

Good question.

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

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

Jim

Personally I would use NEMA starters.
I would investigate using solid state/soft starters if possible, the pricing may be comparable.

I would NOT attempt to build a wye delta start system, if it came down to it I would buy it with an enclosure and remount into the panel, it may be possible to use the existing backplane and mount it into the new panel.

NOTE that at 500HP its going to be size 6 or 7 which will be large and NEED alot of "air space" surrounding it. The specific starter system will designate the amount of spacing needed around it. I would want as MUCH as possible if electronic devices, plc etc, will be in the panel.

I will help any way I can, just let me know.

finding a 500HP wye delta midht be a prob.as most companys are going to autotransformer type. A 500 hp unit would be very large. the factory cabnet would prob. be in the range of 6 to 7 feet tall and 36 inches deep and 6 to 9 feet wide. The last 400 hp starter I bought was in the 20 K range.
regards,
Tom

Tom may be right. A 500HP starter will be a good sized system so may have to be in its own cabinet. That doesnt mean it isnt possible to put in a panel but at that size the panel will need to be very large to supply the "space" needed for and around it.

You could look into a vacuum contactor, it would be smaller and would'nt need as much area around it for cooling as a open contactor would.
Regards,
Tom

If I was building my own, I would look at IEC starters. Above 150A there is not a lot of difference between IEC and NEMA except for physical size. Personally, I would use a solid state soft starter.

I vote for NEMA, also.

IF IEC were used, I would go to a larger size.

When I left GE 10+ years ago, they did some Y-D, but most were autotransformer.

I concur, if at all possible, have it farmed out. Preferably, let a UL shop do it (liability).

regards.....casey

More on "IT" soft start

We supplied a C-H "IT" starter for a 500 HP 460 Volt motor for a mobile machine in Minnesota. Has been operating for 3+ years. The starter is remarkably small, not much bigger than the circuit breaker that feeds it.

Probably only 20% the panel space occupied by a comparable wye-delta starter and maybe 15% of the space used by an autotransformer NEMA 7. No kidding.

The IT starter has internal bypass contactors, so SCRs are out of the circuit when the motor is up to speed. Reduces heat. Fans are on thermostats and only run if SCRs heat up, which might occur in severe duty.

Cost savings are substantial for purchase and installation vs autoxformer or wye-delta, savings due to low material cost, smaller panel and less labor due to far fewer connections.

Starter

My vote goes to what ever they have as a standard.... I think the reduced voltage unit is good but size is BIGGGGGGG... The soft start is much better, but you need a spare. (not just parts).. I personally hated doing PMs on the Allen Bradley Reduced voltage starters. 500HP will need a lot of room and the softstart will be a fraction of the size of any contactor type starter. The boss is the boss man.... if you really have to wire it yourself the prints are available free. Spare parts are everywhere. Ebay just had Allen Bradley contactors and transformers from their starters... but care must be taken here to get the RIGHT parts... We dont want to let the smoke out of the wires etc...
Bruce have a good weekend...

jimpad said:

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

Click to expand...

That depends on how cheap you wanna get....

While your making a decision here on soft start vs W/D ask yourself this..How much is the motor worth? How much labor will it require to replace the motor in the future? How much will the motor shutdown disrupt operations? and for how long? Is this motor a stock item?

Now after you've answered all these questions regarding a 500hp motor...then the soft start starts looking pretty inexpensive..dosent it?

So Jim what you may want to consider is this: Find a good quality soft start & 3 pole contactor that's rated for 60% of the line current draw and wire them inside the delta. Sequence the starter combo so that the contactor picks before the soft start starts, and drops after the soft start stops. There will be no electrical wear on the contactor contacts. Now also...wire the contactor so that it drops out if the fault contact on the soft starter trips.

Like so...

LOL what most people dont understand is...The boss wants a YD starter..Give him a YD starter!! Its like trying to argue with an engineer..Its not worth it..

Granted a YD strter that size will be huge!!! Why worry about a small plc cab sitting beside it..but again...boss/engineers..Personaly i would agree with the others..soft start is the way to go..However..if the plant already has YD that size why change..they have the parts, they have the motor..
Again just My opinion but i think a plc inside this cab would be a bad idea becouse of heat..

Again just my 2c

i agree with darren about the heat. i'm not sure that i would want my plc and its associated parts sitting in that environment, next to a "heat generator". unless your boss is willing to spend some extra money for cabinet a.c. or some other type of adequate ventilation. i have a plc 5/40 mounted in a "duplex" cabinet, right next to a 125 h.p. a-b d.c. drive, and the cabinet does have pass-thru ventilation. we still have problems with the heat generated by that drive. and its much smaller than what your looking at.

just thought..check out Benshaw. A plant i do work at has a 400hp and its sweet!..Stands about 7' hight x 24-30" wide and 12-18" deep..It has fans on the cover for air flow and dosnt get that hot becouse once its up to speen the starting circuit is bypassed. There is also room at the top for a small rack..