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15 hp dust collector 480v problem

15 hp dust collector 480v problem

15 hp dust collector 480v problem

(OP)
I have a 15hp 480v dust collector that I bought used. When I applied 480v power and turn on the power to the motor control cabinet and pushing the start button the motor tried to start.
When I push the start button and hold it in the motor runs fine, but if I release the button the motor will stop.
Can you try to give me some possible things to look for. All fuses at good.



















RE: 15 hp dust collector 480v problem

When the main contactor closes there should be an auxiliary switch on this contactor which closes in parallel with the start button and maintains coil current to the contactor when the start button is released. It sounds like the auxiliary switch is not making correctly, allowing the contactor to drop out when the button is released.

The following link shows the general idea: http://www.seamanship.co.uk/products_/engineering/eng_know-samples/motor_starters.htm

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  Start each day with a smile. Get it over with.

RE: 15 hp dust collector 480v problem

I think that there are better and less ambiguous diagrams available. This one - showing a "contractor" coil, open overcurrent trip contact (should have been an NC contact) and main contacts being too short to do their job - is more confusing than instructive.

Searching the web didn't bring much. Are there no good diagrams available?

Gunnar Englund
www.gke.org

RE: 15 hp dust collector 480v problem

I found the same problem - no decent diagrams! I spotted the 'contractor' typo, but missed the other mistakes.

I wasn't going to post this because it links to a big file, but the 26th and 27th pages of the PDF - marked as pages 72 and 73 in the document - show things properly. And Siemens used proper symbols instead of the horrible ones in Chuck's link! wink

http://www.sea.siemens.com/step/pdfs/cc_3.pdf

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  Start each day with a smile. Get it over with.

RE: 15 hp dust collector 480v problem

Wow ScottyUK

A diagram and education all in one! nice link. thumbsup

Chuck

RE: 15 hp dust collector 480v problem

That's a lot more like it Scotty. Took you some time, heh?

Gunnar Englund
www.gke.org

RE: 15 hp dust collector 480v problem

Good link, Scotty.  Gonna save some time in my next class
prep.  Is the Siemens reference still active?
Any restrictions on using the doc?
Thanks.
<als>

RE: 15 hp dust collector 480v problem

Hi fsmyth, skogs:

Yes, took it ages to find: I wasn't happy with the errors in the reference from my first post, so it had to be improved upon!

Do you mean 'Are the Siemens part numbers being still active?' I think the IEC ones are, certainly the Sirius range is fairly new. Not sure about the NEMA ones.

I'm not clear about restrictions on using the document - it is in the public domain and presumably put there as an educational resource, so I guess as long as you credit the origin of the document, don't alter it and acknowledge their copyright...

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  Experience is what allows us make a completely new mistake every day!

RE: 15 hp dust collector 480v problem

Scotty
You are correct, there are no restrictions on the use of these documents. They are part of a series of educational booklets (called STEP 2000) and include all sorts of useful info from switches to PLC's and drives. I know the chap who wrote the drives booklet and he is more than happy for people to download and read them. They are part of an online training program available via Siemens Energy & Automation in the USA (pity my German colleagues never seem to do such a useful thing...)

RE: 15 hp dust collector 480v problem

Thanks for the confirmation. Pass on my thanks to your colleague too - so much of what is published on the 'net is be appreciated by the readers yet we rarely get a chance to thank the authors.

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  Experience is what allows us make a completely new mistake every day!

RE: 15 hp dust collector 480v problem

ScottyUK
Your link indicaating pages 72 and 73! Are good.
But can you tell me why the OL (overload contacts) are positioned on the neutral side of the coil? I have never fully understood this method.

Thank You
pennpoint

RE: 15 hp dust collector 480v problem

pennpoint,

This is a long-standing controversy.  In general switching of the neutral side of anything is not allowed, but NEMA ICS 2 recommends this location for OL contacts due to the risk of welding of the overload contacts if exposed to short circuits (if control circuit is grounded at some point.)

Since the contacts are normally closed, this problem would not be detected during normal operation.  

The NEC would not allow this for REMOTE devices, but it is allowed for an overload relay that is integral to the starter.

But some engineering firms do routinely specify the OL contacts to be on the other side of the coil.     

RE: 15 hp dust collector 480v problem

Thanks, Scotty.  I always try to attribute the source, if
possible, even if I only use excerpts.  Just seems like the
right thing to do.  
<als>

RE: 15 hp dust collector 480v problem

dpc
I now see the logic.
But you confirmed our procedure, we place it on the hot side of the coil.

Thanks

pennpoint

RE: 15 hp dust collector 480v problem

Why are you letting of the button?
You want the motor to run or not?

RE: 15 hp dust collector 480v problem

Is that a serious question?

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  I don't suffer from insanity. I enjoy it...

RE: 15 hp dust collector 480v problem

There may also have been some remote device in the control circuit that is no longer present. Look for extra holes in the contactor and any sign of wires cut short.

If the starter is in good shape with no unused holes then locate the auxilliary contacts. Locate the coil, one wire from the coil usually connects to the overload relay which is usually below the main contactor. You want the other wire from the coil. Typically this side of the coil will have one wire to the Start Button that you have been pushing and another wire will go to the auilliary contacts. If there are any numbers on the auxilliary contact they will typically be 2 and 3 not L2, not T2,just 2 and 3. If you find the numbers great, if not just follow the wires.
I'm sure someone will jump in and give you the European numbering in case you have a European starter. Find the wire from the coil to the Start Button and look for another wire from the same terminal to another device on the main contactor. This is the device that you want to check. The wire from the other terminal on this device will usually connect to the other side of the Start Push Button.

RE: 15 hp dust collector 480v problem

waross; has a very good point.

Dust collectors are notorious for exploding into flames.  They are perfectly designed for mixing air with combustionable dust.  They normally have lots of fire systems incorporated with them.

There could be some keep alive signal missing now.

RE: 15 hp dust collector 480v problem

Depends on the dust being collected. Sawdust, possibly. Rock dust, no.

Methinks the OP was a one-shot wonder who really had no business wiring up a motor starter to begin with because he had no clue about 3 wire control. He probably replaced the start button with a light switch. Then he'll be upset that the motor comes on all by itself after a power failure! Don't laugh, I have seen it a lot.

Eng-Tips: Help for your job, not for your homework  Read FAQ731-376

RE: 15 hp dust collector 480v problem

Hey ya jraef,

We had a tannery (down here south of you 60mi) in our town and they had a dust collector on a leather sander.  That sucka caught on fire twice a year!!  

RE: 15 hp dust collector 480v problem

Well, at some level any animal product is potentially combustible, otherwise crematoria wouldn't exist! I found out about leather in a different way. It was being used in polishing wheels for chrome in one plant I did some work at, and I saw the explosion proof electrical enclosures. Found out that when the leather polishing wheels emmitted fragments of chrome and leather, it was combustible.

Another one that I came across that I never would have guessed was aluminum dust, but afer seeing many beer cans burn in campfires I should have guessed.

Eng-Tips: Help for your job, not for your homework  Read FAQ731-376

RE: 15 hp dust collector 480v problem

Jraef
I understand that the first thermite welding was done on railway rails. The active ingredient was Alumunum powder mixed with Iron Oxide powder. When the Aluminum burns, it combines with the oxigen in the Iron Oxide. The product of combustion is Aluminum Oxide and Molten Iron. I'm not sure of the composition of a Cad-Weld charge but I understand that Aluminum powder is still an ingredient.

RE: 15 hp dust collector 480v problem

Aluminum dust, yes definitely nasty.

A main constituent of highly active rocket fuel.

Also one of the two constituents of the ever popular Thermite.
Recently a guy who had been grinding aluminium on his bench grinder came back days later and started grinding steel.  Aluminum powder + Iron powder = Thermite.  The hot Iron reached the proper mixture with the existing aluminum dust and the reaction proceeded rapidly.  So fast that his face was seriously burnt along with his clothing.

Yes, Aluminum dust.. Boo Koo flammable.

Amazingly when you grind stuff up small and suspend it in air lots of things are dangerous.

Carbon
Iron
Flour
Cornstarch
Ca  
Mg
Si
Cr
Zn
Cu
Sucrose
Starch
Polyethylene
Coal
Sulphur  


http://www.chemeng.ed.ac.uk/~emju49/SP2001/webpage/

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