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Forum topic by John Smith posted 06-11-2021 12:17 AM 399 views 0 times favorited 16 replies Add to Favorites Watch
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John Smith

2948 posts in 1280 days


06-11-2021 12:17 AM

is there a paddle switch that has BRASS contacts ?
this is the third one I have replaced in maybe 6 years and all stopped working
because of the soft contacts getting burned off.
(you can only file them down so far before the switch is ineffective).

-- there is no educational alternative to having a front row seat in the School of Hard Knocks. --


16 replies so far

View GR8HUNTER's profile

GR8HUNTER

8531 posts in 1829 days


#1 posted 06-11-2021 03:28 PM

maybe you would have better luck with OEM switch as they are built better I M O :<)))))

-- Tony---- Reinholds,Pa.------ REMEMBER TO ALWAYS HAVE FUN :<))

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John Smith

2948 posts in 1280 days


#2 posted 06-11-2021 03:59 PM

thanks Tony – but this is for an old vintage TS and the OEM switch is probably worse off than our cheaper modern replacements.
I ordered a “more costly” model from Amazon and will be here tomorrow. I will check the contacts before installation to see what metal the contacts are.
if they are brass (and not tin) it may be a good recommendation for those that want a higher quality switch.
John

-- there is no educational alternative to having a front row seat in the School of Hard Knocks. --

View controlfreak's profile

controlfreak

2234 posts in 718 days


#3 posted 06-11-2021 04:05 PM

Who is the switch that is getting burned up from? I think I used one from Rockler on my jointer but it is not very demanding and I don’t use it all that much.

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splintergroup

5277 posts in 2339 days


#4 posted 06-11-2021 04:06 PM

If you can find detailed specs, the switches with tungsten carbide contacts are very tough and used for motor (inductive) loads.

Motor contactors are easy enough to find, but totally inclusive as a complete switch is difficult.

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GR8HUNTER

8531 posts in 1829 days


#5 posted 06-11-2021 04:10 PM

please let us know what you find as a good switch is always handy to have around the shop you would think the more expensive ones would be better built :<)))))))

-- Tony---- Reinholds,Pa.------ REMEMBER TO ALWAYS HAVE FUN :<))

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ibewjon

2478 posts in 3910 days


#6 posted 06-11-2021 04:34 PM

Part of the problem is filing the contacts When you file them, the gap increases and the arcing and burning get worse. Then the file comes out again, and the problem gets worse. Is the switch being used over its rated load?

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clagwell

370 posts in 909 days


#7 posted 06-11-2021 07:14 PM

Certainly brass contacts would save the manufacturer money but I don’t think the lower cost would be worth the performance hit. The alloy in the contact buttons is chosen for it’s ability to reduce the erosion caused by the inevitable arcing that takes place when you shut off a motor. That’s why there’s a horsepower rating on a switch. Bigger motors cause bigger arcs and require heavier contacts with greater opening space. What’s the hp rating of the switch versus your motor?

-- Dave, Tippecanoe County, IN --- Is there a corollary to Beranek.s Law that applies to dust collection?

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2Goober

53 posts in 719 days


#8 posted 06-11-2021 07:27 PM

I guess I erased my first response so I’ll try again. Most of the switches from Chinania are overrated. To off set this I use those switches to control a USA made contactor with the correct load rating. It might cost more but it works better. You can also wire the N/O-N/C type of push button switches to control the contactor. This can be safer because if you loose power the machine won’t come back on when is restored (unless you push the start button). There’s several YouTube videos on this.

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2Goober

53 posts in 719 days


#9 posted 06-11-2021 07:41 PM

A good source for good heavy duty contactors would be junk HVAC units. The unit may be junk but the contactors are still very good for our use.

View John Smith's profile

John Smith

2948 posts in 1280 days


#10 posted 06-11-2021 08:08 PM



Part of the problem is filing the contacts When you file them, the gap increases and the arcing and burning get worse. Then the file comes out again, and the problem gets worse. Is the switch being used over its rated load?
- ibewjon

no – that’s not “part of the problem” here:
the switch was brand new when installed. it is rated for 220v/35amps
switch brand name is KEDU: Dual Voltage: 110V/220V; Single Phase
Rated Current: 2 HP / 35 Amps at 120V; 3 HP / 20 Amps at 230V
my saw is 1hp @ 120v/13amps.
a year later, the contacts burned up – so I dressed them up a little – that worked for another year.
this is the 2nd time they have burned up.
filing them to remove some of the pitting in no way interferes with the gap in this particular switch.
(in a 1954 Ford distributor, yes, the gap would interfere with the timing).
this particular switch has a 1/2” gap when open and spring loaded to close.
you could file the contacts (points) all the way down to the nub and it will still work.
[this is not a debate over switches, horsepower, amperages, etc. I am just getting the saw ready to sell)
and when I get a new jobsite saw, I would like to have the same style paddle safety switch for the new saw table.

so a better material for the contact surfaces would solve that problem indefinitely. That is the original question.
if anyone has this particular switch – and you take it apart – be ever so very careful not to loose the little steel balls.

-- there is no educational alternative to having a front row seat in the School of Hard Knocks. --

View ibewjon's profile

ibewjon

2478 posts in 3910 days


#11 posted 06-11-2021 09:59 PM

Sorry, but I have done this for a long while. First rule is to never file or dress the contacts. As clagwell stated, the contacts are designed to take the arcs associated with the on and off. If a switch rated for 35 amps is burning out with 13 amps, it was junk from the start.

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CaptainKlutz

4546 posts in 2611 days


#12 posted 06-11-2021 11:11 PM

+1 Switch is over rated. Kedu HY56 switch is not NEMA or IEC rated, only UL safety listed?
Unfortunately, Kedu in China is only one I found making paddle switches.
FWIW – Most commercial shops use large red mushroom buttons (wired to magnetic starter) for emergency stop buttons.

+1 Do it differently:
a) Use a proper rated manual motor starter switch such as this one.

b) Cobble together a manual motor starter using a definite purpose contactor.
Use a contactor, and let switch turn on contactor. Can buy a honestly rated 40A 3 phase definite purpose contactor for < $20 on Amadud or fleabay. As a safety measure include a 2A inline fuse on switch input power, just in case your wiring is Bork’d or contactor coil fails shorted. Will save your wiring and switch.

c) Use a magnetic motor starter.

Controlling power to motors is not simple. Read the Wiki link above on contactor to learn what is done to deal with arcing due disconnect of inductor/capacitor motor load.
If you want to learn more about motor power control, look up topic on OWWM.org.
One knowledgeable user posted a comparison of IEC .vs NEMA rated contacts showing size differences .vs. current ratings. Don’t have permission to repost, so you will have to go look yourself.

Last but not least: Feel your pain. Have replaced several of those Kedu paddle switches on 1-3/4 & 2HP motors. Have also learned to need to use 5HP+ rated IEC motor starters on 3HP motors, if I want the contacts to last more than a couple years.

Best Luck.

-- If it wasn't for bad luck, I wouldn't have no luck at all, Doom, despair, agony on me… - Albert King - Born Under a Bad Sign released 1967

View BigAl98's profile

BigAl98

274 posts in 4156 days


#13 posted 06-11-2021 11:42 PM

You could use interposing relay…even a solid state one…no contacts.

-- Al,Midwest -To thine own self be true

View 2Goober's profile

2Goober

53 posts in 719 days


#14 posted 06-11-2021 11:50 PM

I’m sorry I didn’t realize you were getting it ready to sell (should have checked my crystal ball). I thought you wanted to correct the problem correctly. (I’ll probably get thrown off LJ for saying that. If ya just want to sell it just slap some turd polish on it and pass it on.

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MrUnix

8632 posts in 3316 days


#15 posted 06-12-2021 12:09 AM

a year later, the contacts burned up – so I dressed them up a little – that worked for another year.

I’ve done just that many times, particularly on the pressure switch for my submersible well pump. It will last a couple of years and then get enough of a build up to make it fail. Well, one time it was due to some ants that were in the wrong place at the wrong time :-O I have an old emery fingernail file that I cut down to fit between the contacts perfectly… couple of back-n-forth swipes with a little pressure on the contact holders and it’s good for another couple of years. Those contacts are made specifically to control the well pump, and sized accordingly, but will still build up enough carbon over time to have them eventually fail. Not a big deal really and easily fixed.

I say just clean up the ones you got and put it up for sale. It will be another year or more before they fail again, depending on how frequently it gets used.

Cheers,
Brad

-- Brad in FL - In Dog I trust... everything else is questionable

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