[How-To] Furmas

markba633csi said:
Agree with Bill: epoxy is worth a try- JB weld isn't the strongest type, but it's cheap and readily available. Cure it at 150-200 deg. F for 3-4 hours for best result. I use a light bulb as a heater, placed near the part. Should have a shiny smooth surface when cured
-Mark
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Do not use JBWeld. It contains metal and would therefore be electrically conductive. There are several brands, JBWeld is the most widely known. There is also "Liquid Steel" and many other "Liquid" names.

WalMart carries a "Hobby Poxy" like brand for just a couple of bux. Clear, in a syringe like dispenser with two tubes that produce the proper amounts when used. It turns cloudy when mixed and hardens clear. Avoid any metal, The best that will happen is it will blow the fuse. Worst case is it will flash over leaving a carbon trail, which is also conductive. Essentially rendering the switch beyond repair.

Once you figure out how to remove the bar, shaping a replacement should be a piece of cake. A piece of a white cutting board from the dime store, Lexan, Nylon, even PlexiGlas, although the acrylic in Plexi is hard and brittle. It should be a simple job for a metal worker to make the piece.

The bar is supported by the enclosure. There should be a slice of a gray cardstock between the bar and the metal. It is Fische paper, an electrical insulator. If the bar is riveted to the metal, the rivet can be drilled out, by hand, until it can be pushed through. A replacement rivet can be fashioned from a piece of wire that is drilled through. Pop rivets can be used, if they fit, by punching out the mandrel and setting by hand.

It would be simple enough to epoxy the two pieces together, taking care to align everything. Use the epoxy to build up the through hole edges, then redrill. But bakelite is very brittle. It would be worth the effort to build a new bar. My favorite material for electrical insulators is the white kitchen board from Wally World.

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projectnut said:
You'll need to know the size of the contactor as well as the model to know what parts may be available. Contactors range in size from 00 to 7. Here's a link to a NEMA chart showing the various sizes, amperage ratings and voltage ratings. Once the size is determined you can do a search on eBay for potential replacement parts.

Nema Starters

Nema sized contactors or starters.
www.engineeringtoolbox.com www.engineeringtoolbox.com

If yours is i size 00 or 0 complete new contactors and most parts are often be available a reasonable cost. As an FYI Furnas has changed hands several times over the years and is currently owned by Siemens. I have been able to find new take off contactors for my older size 0 Furnas starters for only a few dollars. I'm not familiar with the R4 series, but all contactors I have had experience with can be disassembled to replace the contactor points and related hardware.

I found new magnetic coils for less than $20.00 each, and contacts between $13.00 and $18.00 per set.

Another option would be to change out the complete contactor/starter combination for an Allen Bradley setup. I was able to buy a complete NOS control cabinet with relays, reversing starters, including the magnetic coils and contactors for $99.00. If or when the Furnas controls die, or I can no longer find replacement parts at a reasonable cost I'll swap out the complete system.
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Just an afterthought;
The posted device is not a contactor, just a "drum switch". They are common enough, ranging in price from near $100 for a Sq. D to around $15 for a Chinese wannabe.

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I don't believe garden variety JB weld is conductive, although I used to suspect it was because of the color
I have used it for electrical repairs, no problems so far, at least at 120 vac
-Mark
 
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All glued up. Did some grinding with dremel to rough up some. Slots are cut top and bottom for bars to fit into. Plate at bottom with bent over ears to contain. If epoxy doesn’t hold will cut plate and replace bars with cutting board material maybe. Thanks for all help and ideas.
 
In my world the "contactor" you're referring to is generally called a "reversing drum switch". Of all the brands made Furnas seems to be far and away the most expensive. Should you find the gluing is only a short term fix Dayton and Allen Bradley brands are available from a variety of industrial suppliers including McMaster at what I would consider a reasonable cost.

I have several machines that use them. The Dayton brand is usually around $50.00 for a single phase 1 1/2" hp model, while a 3 phase model is in the $60.00 range. To me it's money well spent. I had one fail similar to yours a few years ago. I did epoxy it as a temporary fix. However it wasn't a permanent fix. Within a year it started to fail again and was replaced with a Dayton.

www.mcmaster.com

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.
www.mcmaster.com www.mcmaster.com
 
Got it fixed. Epoxy May have held but didn’t want to repair again in 6 months. So cut strip off wife’s cutting board. Filed. Sanded cutting board so she wouldn’t notice 3/8” missing. Didn’t take her 3 seconds. Be picking up new cutting board tomorrow. CD20823F-AA78-47D1-861B-9BFB9DF12431.jpeg
 
lordbeezer said:
Be picking up new cutting board tomorrow.
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I always keep the old ones for shop use. Great source of plastic for electrical insulators(as you've seen!) and even low-speed bushings.
Dense, slippery and easily worked.
-brino
 
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