Switch

[billmayo]

I buy a black 15' 12 ga extension cord from Lowes. It is cheaper than buying 12 ga cord by the foot. I cut off 5' with the female end and add a male plug to use as a shop extension cord. I strip off a foot of insulation on the 10' cord and use insulated female terminals to connect to the switch. I either use a plastic cord retainer for the cord at the motor pan when the hole is large enough or use an electrical box connector (2 screws) in the motor pan to hold the cord. You must have some way to prevent pulling on the inside wires at the hole in the motor pan. I have found that the motor pan is a very hard metal to cut. I gave up trying to enlarge the hole using a manual electrical box hole cutter. I use a metal cutting burr in my drill press to enlarge the hole now.

No, I have not seen a bad 20 AMP switch. I believe that as a switch is used, you get a very small arc each time when the switch opens or closes. As the spring material gets weaker and is slower to open and close the contact points, it will cause more arcing. This small arcing/burning builds up resistance at the contact points. The more resistance, the hotter the points (switch) gets during normal operations (acts like a resistor) until something burns, melts or no longer makes contact. Bigger and heavier contact points and spring material in the 20 AMP switches helps protect these switches from failure. Of course, I am sure there can be a defective 20 Amp switch due to manufacturing problems and cost cutting these days.

The centrifugal switch points in the motor has the same problem over time. These points are many times bigger/heavier than the ON/OFF switch contact points but they still burn/melt/open causing the start windings to not longer operate correctly.


[quote="dusty"]There is no hijacking here.

I don't know where you can get a cord with a molded plug except to buy an extension and cut the other end off. I sort of prefer the removable plugs my self because I can get a hold of them better (they are bigger) and I am not so inclined to pull on the cord.

Bill]

[JPG]

Good thinking re 20A switch. Another indicator of quality is "HP" rating of switch. Some newer mfg may not include it. Too many switches are rated with no consideration given to "peak/max current" when turning motor on/off(yes both count[max surge 'make/on' and current interrupt 'break/off'].

Red BSEE;)

[a1gutterman]

...I either use a plastic cord retainer for the cord at the motor pan when the hole is large enough or use an electrical box connector (2 screws) in the motor pan to hold the cord. You must have some way to prevent pulling on the inside wires at the hole in the motor pan...

I remember plenty of times, taking apart a radio or small appliance, and having a knot tied in the cord, just inside the housing, to prevent any pulling on the inner connections. They do knot do that knot any more?

[billmayo]

Knotting 16 or 18 ga wires is knot hard. Knotting a 14 or 12 ga power cord is very difficult. The back of the motor takes most of the room inside the motor pan which prevents any knotting of the 12 or 14 ga power cord. Shopsmith used several difficult methods for securing the 14 ga power cord for the Mark V resulting in different size motor pan holes. When switching to a larger 12 ga power cord, none of the original Shopsmith methods for securing the power cord would work for me.

I remember plenty of times, taking apart a radio or small appliance, and having a knot tied in the cord, just inside the housing, to prevent any pulling on the inner connections. They do knot do that knot any more?

[Ed in Tampa]

When I upgraded to 12 gauge wire I was able to get the old wire retainer out of my machine. To use the 12 gauge wire I had to use a file to open the hole a little bit. With the 12 gauge wire in the retainer the overall diameter of the retainer increased, thus a little filing to open the hole in the motor pan.

[JPG]

I do not have any solution to the retaining problems above. but I do want to reinforce what has been said about rigidly attaching it. In addition to possibility of pulling on wires internally we need to also be concerned about "strain relief externally at the point of attachment. My 45 yr oldie HAD a rubber strain releif which was molded to be inserted into a very small hole in bottom of motor pan.

Needless to say it rotted decades ago. I taped it up on the inside to provide a minimal "stop". This does not fix the strain relief problem. Since there is never(almost) any stress placed on it, it has survived.

Fortunately I(with considerable delay/effort) purchased my SS with a 230v motor. This decreases the starting and running current by 1/2, therefore larger wire size in power cord is not an issue. Connects to 20A dedicated branch with receptacle box ON THE FLOOR. not rigidly located

If one has not done replacement yet they may want to consider a liquid tight "connector" which are primarily used for "corded" entrance to liquid tight electrical enclosures (JIC)(machine tools):) Same size hole as romex conn!

[johnm]

If you're using a double pole switch, you can connect both of the poles in parallel and switch only the "hot" wire for the motor, leaving the neutral wire hard-connected. That way you can share the current load of starting and interruption between the two switch poles.

[retcaptb]

I went to http://www.delcity.net/ and found the "strain relief "under the search box . Some heavy duty products that might work for our headstock cord conversions to 12 guage or larger cable.

J. Benson
Grass Valley, Ca.

[JPG]

COOL! Some pix would be nice!

[reible]

Hi,

Now to stir things up a bit.

Here are a few things to think about when deciding to change wire gauges on your shopsmith.

If you use 12 GA wire from your fuse panel to outlet near the shopsmith. And if that run is say 30 feet, then the voltage drop for the run and the 13.5 amp load would be 1.322 volts. Say you add the 10 foot 12 GA cord to the shopsmith then you will loose another .441 volts bring the total to 1.763 for the total run. 120 - 1.763 = 118.24

If the whole run was all 14 GA wire the drop would be 2.801 and the voltage would be 117.2.

If the 30 foot run is 12 gauge then as before you have 1.322 and if the cord is 14 ga that adds .7 or a total of 2.02 giving you 117.98.

Things change when the current goes up. In the first case you have a 40 foot run of 12GA wire, current now at 20 Amps the drop is 2.612. 120-2.612= 117.338

If the whole run had been 14 GA then the drop would be 4.15 volts giving you 115.85.

The mixed run is 1.959 for the 12 GA run and 1.397 for the cord, ending with the voltage at the machine of 116.64

So the farther you are away from the electrical service panel the worse it gets and the higher the current the worse it gets.

FYI I still have 14 GA cords on both of my machines and if you add a foot for the wires inside and then measure the cord at about 8' so the 10 foot number sounds reasonable. I have as a guess about a 25 foot run to the machine so the 30 foot number seems reasonable... I'm still on the original switch on my 1976 machine and who knows about the used one???? Anyway I am not experiencing anything odd and nothing has failed. If the shopsmith is being used I sometimes have a vaccume cleaner plugged in at the same time (a really old one that I think takes about 2-1/2 amps).

The shopsmith manual calls for 15 amp slow blow fuses or circuit breakers and specifies the use of 14 GA extension cords up to 25 feet in length (see page A-4).


So Happy New Year!

Ed