Is there a problem: CN-16 rated contactor with 30A O/L?

[RCxRC]

I was recently looking for a replacement off-the-shelf DOL motor starter for a wood jointer that is configured for 1ph 110v (definitely not industrial grade) and saw this listing for a 2HP rated 1ph 110v starter assembly:

http://www.grizzly.com/products/G8291

The starter is using a Taian "Teco" CN/CU-16 contactor w/110v coil, and an O/L relay with a 22-30A dial range (as visible in the photos shown at this link to the manual):

http://cdn0.grizzly.com/manuals/g8291_m.pdf

Here is a link to the spec sheet for the Teco CN-CU/16 contactor:

http://factorymation.info/motor_controls/CN-9toCN-16.pdf

Per the spec sheet the size 16 contactor is rated (for AC3 rated purposes) at a max of 13.5A under IEC 60947-4-1 spec and 20A under UL508 spec.

I emailed the company regarding the wisdom of selling a starter with a contactor that is rated at 16A continuous / 20A max with a 30A max thermal O/L relay. After several emails with no response from tech support or customer service, I emailed someone in management, who finally responded that they would look into it and get back to me.

Did I over react? Presuming you have 1 ph 110v 30A circuit breakers in place and need this starter, isn't this asking for eventual failure/contact welding/fire?

This is a good company, with a good reputation, and it was out of concern that I considered this when I contacted them.

Thanks in advance,

RC

 

[wayne440]

I don't know if I would call what you did an over reaction, perhaps it is more properly called a strong reaction to an unexpected event, the event being that you suddenly discovered that even a "good company, with a good reputation" will sometimes use components that are marginal for the job at hand.

I'm certainly not an expert on starters, overloads etc. but it is a safe bet that a 30A rated contactor costs more. An increase in production costs means either sell the product at the same price and have less profit, or increase the price and lose some sales (and the profits thereof). It is often better from a profit-taking point of view to use a cheaper part and figure on a few warranty replacements.


The days of building a product to last decades are long gone, replaced by building to last just beyond the warranty period in some cases. Sadly, this is such a common practice that most people do not expect a product to last much beyond the warranty these days. The "eventual failure/contact welding/fire" that happens beyond the warranty is not going to be an issue for the vendor 99.44% of the time.

 

[panelman]

That whole data sheet looks dodgy, apart from the use of a 30A overload with a 16A contactor they only use two poles of the overload which I would have thought would have caused tripping on current imbalance.

Over in the UK the Teco brand was the first of the super cheap far eastern imports, the quality isn’t perfect although to be fair any faults tended to be DOA rather than early failure on site.

They’ve now been displaced at the bottom of the pile by even cheaper Chinese imports although I think they are badged up and sold under the Harvey Hubble brand

 

[jraef]

Yep, they have made a classic error of reading only some of the numbers and none of the application notes. they probably saw the Thermal Current rating being 32A and figure that was all they needed to know. Happens all the time with exporters.

You are correct, they are in violation of the UL listing of that device. If it caused a fire, someone is going to get in trouble...

As to the OL tripping on single phase, you're right but that actually would probably never happen because that contactor would fry long before you got there!


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[RCxRC]

Panelman; the good guys at Magnitrol, an excellent, highly regarded motor / controls shop in San Fernando, CA, said the same thing when they looked at the Grizzly schematic (using only two poles for the overload).

I appears that they simply decided to squeeze in the same contactor for nearly their entire line of off the shelf DOL motor starters. I don't know if that was intentional, or on the part of the vendor they're dealing with.

Jraef; this is designed for a wood shop jointer. Plenty of kindling!

These were some of the least expensive complete DOL starters available, running in the $60 range. If my research is correct, they're made in one of Taian's mfg facilities in the Phillipines.

Weg's similar product runs around $100. GE, Square D, etc start at $250 and up.

Caveat emptor.

Thank you for all of your input. I didn't think 16 years of working for a school district had made me too obsolete.

Regards,

RC