# Adjustable soft starter



## Helmut (May 7, 2014)

So I went yesterday to hook up that replacement motor, and run it.
I figure I'll check the heaters while I'm there.


The heaters are for a 200HP motor. Apparently they use the same setup for any size motor up to 250Hp.

I suppose you can see the problem, and maybe why they burnt the last motor up.


Getting to my question, I kinda think I can sell them on upgrading this starter to an adjustable/soft starter, 

What would you do?


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## MDShunk (Jan 7, 2007)

I could go either way on that. In my mind, there should be some compelling reason to justify the expense. You can get the right overload heaters for the existing starter for 150 bucks (off the top of my head) or you can get probably the Allen Bradley 150-F251NBD soft start for $5015 dollars (real pricing from my vendor). That soft start price is about the same price as a new 504 frame 150hp motor, so the customer would be completely justified in considering the cost of a new motor purchase potentially earlier than normal versus the cost of a soft start when weighing the options.

Some reasons that justify a soft start:

lower demand penalty starting a large motor
no winkng lights
elimination of coupling breakage
elimination of squealing belts
elimination of motor mount/skid breakage from starting torque.
better motor health monitoring
perhaps, longer motor life
Some reasons to just put in the proper overloads:

cheaper fix
it exists and already works
flying restart is more easily accomplished with a traditional starter vs soft start, which may or may not be a consideration here.

If you go the soft start route, be advised that they are available in 24vdc and 120/240vac control, so you'll need to sort out what the control voltage is for the existing stop/start arrangement. (edit: I note what looks like a 240v control power transformer in that bucket) If there are frequent restarts, the optional fan kits should be investigated. I've personally never had any special issues getting a soft start to fit in existing buckets, but it's prudent to get dimensions off the proposed soft start cut sheet to be sure. I've heard that depth can sometimes be an issue. 

Know also that a soft start, since it's an electronic device doing closer monitoring of the motor, control circuit, and connected wiring, may discover other issues from time to time that were otherwise undiscovered or would have gone undiscovered. This has the potential to give the customer the impression that "that damn thing don't work right", when in reality it's pointing to existing issues or flagging new issues in the future that would have otherwise been unnoted.


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## Peewee0413 (Oct 18, 2012)

What in the swirl is that tape doing...

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## paulengr (Oct 8, 2017)

The soft start depending on brand can also put current on the motor stator as a heater, eliminating components and making it more reliable.


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## Cow (Jan 16, 2008)

Those style of Eaton starters last forever as you can see. I'd open it up and verify the contacts and coil laminations still look good. If so, I'd give them a price for proper heater replacement and a price for a softstart upgrade while mentioning the handful of advantages of a softstart. 

Then I'd let them choose, with no pressure either way.


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## frenchelectrican (Mar 15, 2007)

I would go either way depending on what kind load the motor is driven.,,

compressors useally work the best with direct on line or soft start with high toqure kick over feature on it. 

Just keep in your mind with soft starts it useally take little longer to get it up to running speed compared conventail starting system is.


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## paulengr (Oct 8, 2017)

I wouldn't use the AB for three reasons. First it's about 250% markup.

Second, it's made in Europe and those are all notoriously unreliable. AB is selling the old Sprecher-Schutte polish stuff. The most reliable American made soft start is Benshaw. Mr. Benshaw was a Pennsylvnia coal mine electrician who was disappointed with the extremely poor build quality of the European soft starts and began building them in his garage. It's currently the largest soft start manufacturer in North America for good reason. Allen Bradley is the best for contctors and Benshaw is the "AB" of soft starts. The other options for US made would be Motortronics and Square D. All three are factory stock next day delivery. I service and sell all three. Well sort of. Being a Benshaw tech is like the old Maytag commercials...I don't usually work on any that are less than 20 years old. I also do AB, ABB, and anyone else, at least up to 12.5 kv.

Third unlike the AB you can easily replace the power sections and the control board independently instead of junking the whole thing.

Fourth kick is not the best way to start compressors. During starting the torque goes up with the square of speed so starting torque is low but rapidly increases. The trick is to current limit start them with a 350-400% current limit. This gives you a short 6-8 second start and won't trip breakers and fuses while still limiting starting torque. Kick is meant for processes that have a lot of breakaway torque but then start easy like a sliding load, the opposite of what compressors do.



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## MDShunk (Jan 7, 2007)

Alas, some of us don't get to pick. So many companies have standardized on brands. I think everything AB makes is way overpriced, and I agree that their drives and soft starts, while not the worst available, are not among the longest lived options in the marketplace. I've also come to the conclusion that AB makes almost nothing themselves. Spend enough time in the trade and you begin to recognize the OEM of most of their stuff. I can recall an AB lunch and learn a short while back where I told the rep that the safety relay and guard switches he was "teaching" us about weren't even made by AB, and he denied it... so I went to our parts room and pulled out the exact same items with the OEM's branding instead of AB's. This was after he told us "he'd been to the factory". In Czechoslovakia? lol

Having said that, my price on the equivalent Benshaw from my vendor is 4664.81. Only a few hundred less than the AB.


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## Helmut (May 7, 2014)

frenchelectrican said:


> I would go either way depending on what kind load the motor is driven.,,
> 
> compressors useally work the best with direct on line or soft start with high toqure kick over feature on it.
> 
> Just keep in your mind with soft starts it useally take little longer to get it up to running speed compared conventail starting system is.



It's a vacuum pump. No load at start. It exhausts to atmosphere until up to speed, and then engages vacuum valves, if it matters.
I don't believe you can start it under vacuum, because valves open with power loss.


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## JRaef (Mar 23, 2009)

First off, that is a NEMA size 5 starter, max on a Size 5 is 200HP, so you likely cannot get the right heater elements for it for a motor that is too big for the rating. On the other hand, using heaters for a 200HP would not have harmed that 250HP motor, worst case scenario would be nuisance tripping, but that’s not inherently harmful to the motor. If it was not nuisance tripping, it’s probably indicative of the fact that the LOAD on that motor is less than 200HP so the OL heaters were not tripping. 

This is ASSUMING someone didn’t “force” the incorrect heater elements into that OL block, people do all kinds of bad things like that. So now OFFICIALLY you have taken ownership of this situation in that you are the last one to touch it, so using the incorrect heaters becomes your responsibility. I for one wouldn’t do it and inform the owner that the previous installation was a code violation (110.3, suitable for the intended use) do it has to be changed one way or the other, then if dpung so, a NEMA size 6 starter is likely going to cost a lot more, and the Soft Starter would be less of a difference. 

Don’t know shere all that stuff came from about A-B soft starters, but it’s untrue. A-B bought Sprecher and Schuh (Schuh, not Schutte, Swiss, not Polish) and the soft starters sold by S&S are brand labeled from the US, not the other way around. S&S basically sells the older model North America made soft starters. 

And there was never a “Mr Benshaw”, I used to work for Benshaw. The founder of the company was Bob Schaltenbrand, the Vice President of a US branch of Saftronics, which was from South Africa (South AFrican Electronics), but had to separate because at the time, South Africa was still doing Apartheid and was unpopular in the US. But Bob didn’t get along with the other owners of Saftronics US and SAF Canada, their sister company, so he stole the designs of the original South African designs and started a separate company. Eventually he settled out of court with the Daftronics and SAF Canada people over the copyright infringements but by then, neither company was still using the old design anyway. Bob got cancer and drove himself into a tree a few years later, then his family sold the company and not it is part of Regal Beloit. 

Motortronics is FAR larger than Benshaw by the way. They brand label their MV soft starters to Toshiba, GE, Siemens, ABB, Eaton and a couple of smaller EU and Asian companies. Their MV soft starter sales alone eclipse Benshaw total sales. And Square D soft starters are ALL Telemecanique from France, no US mfg whatsoever.


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## MDShunk (Jan 7, 2007)

He's dealing with a 150. Not a 250.


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## Helmut (May 7, 2014)

125Hp with 200hp heaters, jumpered out.


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