# size 5 starter



## Southeast Power (Jan 18, 2009)

Maybe the coil is going bad??


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## wwilson174 (Apr 25, 2008)

ampman said:


> need some help - i got a size 5 sq d starter that is making a lot of noise ,tried cleaning with no luck ,i have always been able to clean and make them quiet. any help please


 
Starters of that size typically are equipped with DC coils powered by an onboard bridge rectifier. You might test those components for proper operation. BillW


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## chicken steve (Mar 22, 2011)

That's a big starter, so my first q would be, where is the soft start?

i'm going to eat my broccoli, and think about this......

~CS~


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## Jmohl (Apr 26, 2011)

Anything that big, I personally have never seen start across the line. Had a re-therm with a 125hp with an A/B VFD.


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## McClary’s Electrical (Feb 21, 2009)

chicken steve said:


> That's a big starter, so my first q would be, where is the soft start?
> 
> i'm going to eat my broccoli, and think about this......
> 
> ~CS~


Why would you need a soft start AND a starter?

Size 5 is common around here. Normally a buzz is the sign of a failing coil, or often is caused by dirty control power on that coil.


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## ampman (Apr 2, 2009)

jrannis said:


> Maybe the coil is going bad??


 260va max written on the coil it draws 1.3 a @ 120v


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## ampman (Apr 2, 2009)

wwilson174 said:


> Starters of that size typically are equipped with DC coils powered by an onboard bridge rectifier. You might test those components for proper operation. BillW


 coil is ac


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## ampman (Apr 2, 2009)

Jmohl said:


> Anything that big, I personally have never seen start across the line. Had a re-therm with a 125hp with an A/B VFD.


 this is very old, newer installs require that you check with the poco about across the line starting or soft starting


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## ampman (Apr 2, 2009)

mcclary's electrical said:


> Why would you need a soft start AND a starter?
> 
> Size 5 is common around here. Normally a buzz is the sign of a failing coil, or often is caused by dirty control power on that coil.


 control is tapped from line side and this is more than a buzz it's unbearable


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## Jmohl (Apr 26, 2011)

ampman said:


> this is very old, newer installs require that you check with the poco about across the line starting or soft starting


The inrush on something like that has gotta be huge.... do the lights dim?


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## Jlarson (Jun 28, 2009)

ampman said:


> tried cleaning with no luck


Did you clean the magnet faces? 

One of the shading rings is probably broken.


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## mrmike (Dec 10, 2010)

This is very common in Industry. Clean the coil where it pulls in the contactor & change the contacts or "burnish" them, Change the operating springs, & clean the "slides" which are the grooves that keep the contactor in line, so the contacts meet together on even terms. Once in a great while, the coil would get weak & we had to change that out...........


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## ampman (Apr 2, 2009)

Jmohl said:


> The inrush on something like that has gotta be huge.... do the lights dim?


 inrush current is 3 amps for about 1/2 sec. then it goes to 1.3 steady


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## ampman (Apr 2, 2009)

Jlarson said:


> Did you clean the magnet faces?
> 
> One of the shading rings is probably broken.


 i did clean the mag faces ( this usally solves the problem) but i did notice that the grove where the shading coil is had some filler material missing but no sign of a broken SC


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## ampman (Apr 2, 2009)

mrmike said:


> This is very common in Industry. Clean the coil where it pulls in the contactor & change the contacts or "burnish" them, Change the operating springs, & clean the "slides" which are the grooves that keep the contactor in line, so the contacts meet together on even terms. Once in a great while, the coil would get weak & we had to change that out...........


 owner bought new contact kit (check prices on these lately) took completly apart and cleaned with CC i can push in on the coil and reduce some of the noise


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## Jmohl (Apr 26, 2011)

ampman said:


> inrush current is 3 amps for about 1/2 sec. then it goes to 1.3 steady


not the coil, the motor itself, actually, thinking about it, we do have a couple of 150hp compressors that start across the line, Brain fart.... we are actually looking to retrofit with a VFD.


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## ampman (Apr 2, 2009)

Jmohl said:


> not the coil, the motor itself, actually, thinking about it, we do have a couple of 150hp compressors that start across the line, Brain fart.... we are actually looking to retrofit with a VFD.


 the noise is contstant any time the well is running not much VD when starting , the PM does not even act up


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## chicken steve (Mar 22, 2011)

mcclary's electrical said:


> Why would you need a soft start AND a starter?
> 
> Size 5 is common around here. Normally a buzz is the sign of a failing coil, or often is caused by dirty control power on that coil.


 
ask your local poco lad

~CS~


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## sparky970 (Mar 19, 2008)

Jmohl said:


> The inrush on something like that has gotta be huge.... do the lights dim?


We had a 575V, 88hp cooling tower fan motor that was started AOL. I put my 1000A clamp meter on it and closed the door. After it started it showed about 650A inrush. We also found that sometimes when the fan was off, the draft through the fan blades would make it rotate backwards. This was noticed after some broken mechanical parts and an exploded breaker.


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## RIVETER (Sep 26, 2009)

wwilson174 said:


> Starters of that size typically are equipped with DC coils powered by an onboard bridge rectifier. You might test those components for proper operation. BillW


I've been around awhile and I did not know that. Is that correct? If so, why would a dc coil on a motor be any better? In this case I am thinking the lamination's are loose but what do I know?


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## bthesparky (Jan 23, 2009)

shading ring is def. where i'd be looking. If you can put pressure on the plunger and the rattle goes away it means your shading ring is generally bad. the buzz is the plunger wanting to release as the ac power sine wave goes through zero, the shading ring provides means to keep charge while this happens so you don't have the constant buzzing like your having.


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## wwilson174 (Apr 25, 2008)

RIVETER said:


> I've been around awhile and I did not know that. Is that correct? If so, why would a dc coil on a motor be any better? In this case I am thinking the lamination's are loose but what do I know?


 
DC coils have a lot more power than their AC counterparts, necessary on large starting currents where a bouncing contact can cause severe arcing and welding. They are easy to recognise because of the circular shape of DC coils. AC coils are rectangular in shape,BillW Starter coils running on DC voltage will hold on much lower voltage levels than those that operate on AC voltages. Typically, coils running on DC will hold on voltages down to about 30% of nominal, instead of 80% as is the case for those that run on AC voltage. This almost always solves the starter coil chattering problem on low-voltage motors.


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## McClary’s Electrical (Feb 21, 2009)

chicken steve said:


> ask your local poco lad
> 
> ~CS~


We can start up to 150 hp across the line and we service a ton of 400's that start Wye/delta.


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## JRaef (Mar 23, 2009)

Vote #2 for the broken shading coil, especially if you are ABSOLUTELY SURE that the pole faces are clean and unobstructed. It happens. You would not need to be able to see anything, it could simply be cracked somewhere and the fluxing effect will be reduced.


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## John Valdes (May 17, 2007)

chicken steve said:


> That's a big starter, so my first q would be, where is the soft start?
> 
> i'm going to eat my broccoli, and think about this......
> 
> ~CS~


Soft start allows complete removal of magnetic starter. 



mcclary's electrical said:


> Why would you need a soft start AND a starter?
> 
> Size 5 is common around here. Normally a buzz is the sign of a failing coil, or often is caused by dirty control power on that coil.


Agree on the soft start. The buzzing could be anything. I am like the others. Shading coil, cleaning of mating surfaces ect......



wwilson174 said:


> Starters of that size typically are equipped with DC coils powered by an onboard bridge rectifier. You might test those components for proper operation. BillW


I never see DC coils, especially on NEMA starters. DC is common however on IEC contactors.



ampman said:


> owner bought new contact kit (check prices on these lately) took completly apart and cleaned with CC i can push in on the coil and reduce some of the noise


Thats why we went to brands like Benshaw. When I was in this business we could replace a NEMA 5 starter complete with OLR and aux contact kit for $700.00. A NEMA 5 starter is 3 or 4 times that much if you go NEMA and Square D.



wwilson174 said:


> DC coils have a lot more power than their AC counterparts, necessary on large starting currents where a bouncing contact can cause severe arcing and welding. They are easy to recognise because of the circular shape of DC coils. AC coils are rectangular in shape,BillW Starter coils running on DC voltage will hold on much lower voltage levels than those that operate on AC voltages. Typically, coils running on DC will hold on voltages down to about 30% of nominal, instead of 80% as is the case for those that run on AC voltage. This almost always solves the starter coil chattering problem on low-voltage motors.


I have never heard this. DC stronger than AC? I am not saying you are wrong or that your holding percentages are wrong, but where can I see this for myself? 30% of rated DC voltage will hold the contactor in? Thats what I what to know. Please assist.


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## JRaef (Mar 23, 2009)

A lot of larger contactor coils are DC, whether you realize it or not. The rectifier circuit may be embedded in the coil or attached right to it, so when you wire it up, you are wiring your normal AC control power to it. But inside, the coil is DC in order to save coil power and therefore heat in the starter. DC for coils is more efficient when holding in, and large starters are typically used on things that run for a long time where that becomes an issue as opposed to small motors that may bang on and off rapidly.

Many of the larger IEC contactors like Siemens or even the Korean (LG) one that Benshaw brand labels have now gone to solid state coils, which are also DC coils inside with a little SMPS built in. This is what allows them to sell one coil that works on anything from 24VDC to 290VAC.


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