The A-B SMC-50 Soft Starters can be de-rated for operation up to 65C. But it is ONLY the SMC-50, not the SMC-Flex or the SMC-3, so be specific. They use an app called the "Thermal Wizard" to calculate the de-rating, have your local A-B distributor run that for you.

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

There are cabinet manufacturers that have AC cooling aggregats as a option.
This of course makes the installation, running and maintenance cost higher but if it is a crucial function it might be worth it.

Soft starters usually have a recommended limited amount of stopp starts in an hour, due to the heat development during start, something to look out for.

Maybe the old solution with Y/D start by contactors would be better.

Best Regards A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

If it's in the USA, we do resistor banks or autotransformer based soft starting. The Y/D motors are rare.

jraef - I'm familiar with the SMC-3. I like AB products but I try to avoid them because our AP girl got into some drama with the only local distributor.

I know it's pathetic; but, it is what it is.

RedSnake - This is on a farm that's 2 hours drive from me. I'd REALLY like to avoid all the additionals that come with AC. Simple is good.

TugboatEng - They're autotransformer panels now. They've been baking in the Arizona heat for 30 years. Everything in the panel is rusty/crusty and buzzing and all the little plastic shit keeps breaking. The customer just wants them replaced so they'll be reliable.

It seems like the price of a single soft starter with internal bypass is comparable to two NEMA starters and associated control components/build time?

I probably should have started by letting you all know that I'm not an engineer. I'm a hack instrumentation and controls tech.

My company primarily drills/services wells. We have a small electrical division. They had one I&C guy that hired me and quit 4 months later. I've been figuring it out for 3 years. I never build panels but we are a 508A panel shop. I got my MTR cert a couple of months ago so I'm somewhat familiar with the process. I kinda want to handle this entire job myself. They're simple panels. Might be a good place to start.

That being said, I have a habit of biting off more than I can chew.

Here is one +60C
https://search.abb.com/library/Download.aspx?Docum...

BR A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

Buzzing? The autotransformer style requires 3 contactors. One of the contactors de-energizes the autotransformer after the motor start. I know the pneumatic time delays fail with age and it's possible things have been bypassed. The buzzing may also come from the control transformer if it's a big one.

If you want robust, the Allen-Bradley Bulletin 702 contactors were the best of the best but they have been discontinued. The Allen-Bradley Bulletin 500 and Square D Type S contactors are also very robust. Keep everything NEMA, use 30mm controls, derate all components, and avoid anything that says IEC when you build your new super panel.

It is not unusual that both relays and contactors to start bussing with the net frequency when they get mechanically worn, when they are energized.
They can work for 10 to 15 years longer without a problem.
We exchange them as soon as they start bussing mostly because it's dam annoying.

But at 30 years at that environment they have done there time.

If you want a reliable and simple solution you should do as tug suggests and replace it with a new equal one.

Best Regards A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

sferrari; One of the best tricks we used for all the desert control panels was to always require and include sunshades. Often the enclosure gets mounted on a pole or standing Uni-struts. We'd always spec or include a little corrugated roof so the enclosures never got direct sun.

Keith Cress
kcress - http://www.flaminsystems.com

I talked to the Product Manager for our local AB distributor. He was pretty cool.

I decided to go with the SMC-50 and a sun shade. The enclosures are already ventilated. He feels pretty confident heat won't be an issue.

He confirmed what I kinda already knew. The autotransformer panels are pretty much obsolete now and when all is said and done they cost roughly twice as much as a solid state SS.

I appreciate all the input.

Should I post pictures when I'm done?

Yes please do, a before and after.

/A

“Logic will get you from A to Z; imagination will get you everywhere.“
Albert Einstein

sferrari:

Where in AZ? Just curious, I am west of Phoenix.

-AK2DM

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
"It's the questions that drive us"
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Since this is for a pump, I have to ask why you think you need a soft starter at all? A utility requirement? (These utility requirements for reduced-voltage starting above some arbitrary motor size is a longstanding pet peeve of mine.)

dpc,
Usually what drives the requirement for Reduced Voltage Starting (of any sort) is a starting requirement, often arbitrarily set by the utility at some value such as 50HP, 100HP etc. But Soft Starters on pumps also add a way to control the deceleration profile to avoid creating water hammer.

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

No knowledge of that particular case, but utilities really do like one size fit all answers. If I have an answer that can fit any system configuration, including odd paralleling during switching that’s the answer you’re going to get. No trying to calculate site/time specific answers that could wrong tomorrow after a car-hit-pole incident tonight.

I’ll see your silver lining and raise you two black clouds. - Protection Operations

So David, let's assume you have two customers - one with a 200 hp motor and one with a 500 hp motor. If your system can handle the 500 hp motor start using reduced voltage, how is that much different than starting a 200 hp motor across the line? Maybe you should require all motors be on soft starters. It makes more sense to have actual system performance criteria. Other than the impact on the distribution system, why should the serving utility be involved in how they start their motors?

We've got some shills for "big soft start" in here🤣

What happens when tbe 500hp customer and the 200hp customer both start their motors simultaneously? The outside world loves to create worst case scenarios. Might as well require both to be on soft starters.

The 500 HP motor may be on a much larger transformer than the 200 HP motor. That will mitigate some but not all of the starting voltage dip.

Bill
--------------------
Ohm's law
Not just a good idea;
It's the LAW!

I was thinking both motors on the same transformer. Without interlock, they could both start simultaneously. That would be a good reason to require soft start on both despite having the capacity to DOL the 200hp motor.

That's a damn good question. I'm just assuming that the SS is a utility requirement. I just called and they're closed at noon on a Friday? Nice.

The utility has one chance to tell the customer what needs to be done and that answer has to suffice for all system configurations and for the rest of time. Can't go back and tell the customer that they've got to change starting methods later when something happens. Maybe that motor can be started across the line without adverse impact 90% of the time, but 10% of the time the feeder is in a different configuration and rather than being close to the substation with a strong source it's at the end of a different feeder from a different station with a weaker source. Unlike most commercial/industrial power systems that tend to stay the same for long periods of time, much of the utility distribution system is very dynamic in configuration. Most commercial/industrial power systems don't have to be prepared to deal with a car taking out a pole or a getaway cable failing and needing to routed around.

I’ll see your silver lining and raise you two black clouds. - Protection Operations

I believe the utilities have a legal requirement to deliver power to users without more than x% flicker. The only way to guarantee that is to limit the starting current hits from things like DOL motor starts of motors bigger than some size. They get to state a SS requirement for motors over xHP by simply pointing at their required flicker limits. Then they follow thru as davidbeach pointed out - forever.

Keith Cress
kcress - http://www.flaminsystems.com