# 10 hp soft starter



## Cow (Jan 16, 2008)

They don't need a soft start, they need to tighten their belts. I've wired plenty of fans and have never needed to install a soft start for squealing belts.


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## emtnut (Mar 1, 2015)

hydro said:


> Morning boys. I've been working on a commercial woodworking shop for a couple months. The client had a 10 hp dust collector installed about a month ago. The last couple of weeks the belts have been squealing like crazy and it's getting worse. I'm thinking they need some kind of soft starter but I have zero experience with them. The motor is a 10 hp 600 volt with about a 9.5 amp fla. Anybody with more experience have an idea of what I should be using? Thanks in advance.


Belts stretch ... It's what they do !

If the bearings aren't sealed, and/or old and dirt getting in, that could be the problem too.


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## JRaef (Mar 23, 2009)

You don't need a super sophisticated soft starter for that, but don't go with the cheapest either. Most of the cheap ones now get there by putting SCRs on only 2 of the phases instead of all three. It works, but it's really bad for the motor and runs an extreme risk of burning it out on single phasing if even one of the remaining SCRs has a problem. 

I'd recommend an AB SMC-3, but that would be unethical of me because I work for them now, so I won't do that.


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## weebee (Feb 15, 2016)

JRaef said:


> You don't need a super sophisticated soft starter for that, but don't go with the cheapest either. Most of the cheap ones now get there by putting SCRs on only 2 of the phases instead of all three. It works, but it's really bad for the motor and runs an extreme risk of burning it out on single phasing if even one of the remaining SCRs has a problem.
> 
> I'd recommend an AB SMC-3, but that would be unethical of me because I work for them now, so I won't do that.


Well, I don't work for them so I'll recommend them! We use them on 10-20 hp blowers and they work fine. And they are not $$$. I would still check the belts first though.


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## micromind (Aug 11, 2007)

JRaef said:


> You don't need a super sophisticated soft starter for that, but don't go with the cheapest either. Most of the cheap ones now get there by putting SCRs on only 2 of the phases instead of all three. It works, but it's really bad for the motor and runs an extreme risk of burning it out on single phasing if even one of the remaining SCRs has a problem.
> 
> I'd recommend an AB SMC-3, but that would be unethical of me because I work for them now, so I won't do that.


I don't work for AB but having installed a bunch of SMC-3s over the years, I would highly recommend them. Some I've installed are for motors up to 300HP. Not a lick of trouble with any of them.

Really easy to program; it's a bunch of dip switches (tiny slide switches behind a small cover) and a dial for the motor current. 

Replacing a basic starter with a soft-start isn't quite as easy as it may seem.....

1) Just about every soft-start I've ever installed needs separate control power. Most can be ordered for either 120AC or 24DC. 

2) Some will fit in the original enclosure, a lot won't. They're usually too deep. Getting one with a factory enclosure can be a real trick sometimes.

3) As noted, there is a lot of basic cheap junk out there. Pay a bit more for a reputable brand. 

4) The ones with built-in bypass contractors are always best. With no by-pass, they generate quite a bit of heat and the enclosure will need to be ventilated at the very least. The ones with by-pass contractors generate very little heat. 

5) A lot of them have only one auxiliary contact. If you need more than one, you'll need to mount a relay. 

6) Occasionally, because of the ultra-low power of the inputs, standard pushbuttons, switches and relays won't work or they'll fail intermittently. Further, they don't do well with control and power in the same conduit. This can be easily solved with a relay though. 

In your situation, if the belts are squealing during starting, that's pretty normal. If it's an issue, a soft-start will absolutely keep them quiet. If they're squealing during full-speed operation, a soft-start won't help at all. They are either too loose or glazed. 

Rob


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## Wirenuting (Sep 12, 2010)

Belts wear out. 
The sheeves also wear out quickly if the belts haven't been replaced when needed. 

When the belt is off, feel the inside of both sheeves. They should be smooth and not stepped or uneven. 
Replace with the same size sheeves and new belt of the same type and size.


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## garfield (Jul 30, 2009)

moved


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## MechanicalDVR (Dec 29, 2007)

Most dust collection systems I've heard start have belt whine for a few seconds, never had to install a soft start on any of them. Adjust the belts, lube the bearings, and don't over engineer the wheel.


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## garfield (Jul 30, 2009)

I haven't worked on blowers much but quarries and grain equipment the problem is usually worn or loose belts. You can check with a straight edge and see that it touches 4 points on the 2 pulleys. This will keep the belts from wearing prematurely which makes them get loose. You might take along a new belt to hold in the b groove or whatever they are and see if the existing belts are deep into the groove... that means they are worn out. If the belts and shaves are new and properly sized and designed then you put new belts on and you should have to tighten them once in a month or so then they should run for a long time with no attention and no slipping. Again if they are properly designed etc you shouldn't need a soft start. I have found 1/2 of the time a little mechanical knowledge is more helpful than electrical diagnosis. https://www.pennbarry.com/public/support/how%20to


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## Flyingsod (Jul 11, 2013)

I'm just agreeing with the majority here. Soft start is nice but def not needed. Having just completed its first month of service its time for a nut and bolt tightening party. Have the customer provide or obtain maintenance specs from the manufacturer. Or better yet since its new contact the installer or manufacturer for warranty work. This in all likelihood is a mechanical problem not an electrical one.


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