BT3100 - 2nd switch failed

[wd4lc]

don't know why the second switch failed; ryobi was replacing them with switches with a stronger spring i think that pulled the switch apart faster and harder so it would not have time to weld together the contacts when they were opened. this was the early switches on the BT3100s.

I assume the guy you got it from was tom clinkscales, Ryobi/TTI customer service manager for a long time?

I have not heard the replacement switches failed and i've been reading posts on this forum for a long time.

Thanks for the response, Loring. It sounds as if from your post and a couple of other responses that the switch may not be the fault. Reading over some older threads I see that using an extension cord may not help matters. I do use an extension cord (I'll have to check the rating later but I think it is fine). Admittedly I also have a box fan, clock radio and shop vac plugged into the other half of the receptacle through a plug squid. I've never had a problem with this setup before.

The person who helped me in terms of the replacement switch was a fellow by the name of Wayne Hill. Looking it up this was about 2-1/2 years ago.

Is there anything I can do to determine the cause of the problem? I did unscrew the switch case from the saw to make sure that the connections were all in place. That was about the extent of my inspection.

Other notes. I was ripping 2x4 cedar at the time which I know (ripping) can bog down the table saw. My only thought is that I've done this before with no problems. Of course I know that this really doesn't mean anything as anything can change.
Since then, a plug strip (basically a house plug power strip with no surge protection) that has an on/off switch was used to power on/off the table saw. This did work fine for quick tasks but tripped the house breaker when longer tasks (such as ripping) occurred. To you and RAFlorida I ask is this fine to use (as a very brief temporary fix) until I get a new switch? I'm not concerned about the power strip getting damaged. I'm more worried about the table saw and/or house. I do not know very much at all about electrical work or codes.

Thanks.

[wd4lc]

After repairing my original switch twice, I replaced my switch on the saw with the new style switch, and added an "auxiliary switch box" between the saw switch and the power cord, using 15-amp household switch and outlet in connected single-gang boxes. I consider this a safety feature, since I must first turn on the saw switch which is unpowered until I turn on the ASB, which closes the power circuit. When I am done for the day, I turn off both switches, so I don't get any accidental power-ups from bumping the ASB. I believe this arrangement prevents any arcing in the saw switch, because the contacts are already closed when the ASB is used to supply power to the circuit.

I mounted the ASB to the underside of the front rail, where it happens to be easier for me to reach. Not pretty, but functional for me. I'd be interested to hear how the OP resolves this problem.

That looks great, Bill. I wouldn't have a clue on where to start with that. I'd love it if I could pull something like that off.

[wd4lc]

I have not had any problems yet. But I have been looking a switch sold buy Rockler.com item number 20915. Hope this helps.

Thanks dlthrift. That actually looks familiar. I think I've seen that one recommended before. I'm going to see if Rockler has others as well.

To all, if I'm looking for a more heavy duty switch should I be looking for a higher amperage rating (higher number than the saw number)?

Also for these replacement switches is it a matter of twisting 2 sets of wires together (and wire nutting them) or is there more involved?

I'll keep reading other threads. Seems I remember someone talking about a pedal switch awhile back.

Much appreciated everyone.

[woodturner]

Couldn't a guy use a simple solid state relay to take the load off the switch?

Yes, if it's rated to handle the motor load.

It's the inductive surge that Loring referenced that causes the problem. The coil widings in the motor cause a surge in the "wrong" direction that tends to blow out solid state relays. One common fix is a snubber diode, and you can buy solid state relays intended for motor applications that already have those installed.

The optimal answer would probably be a magnetic starter.

[Tom Slick]

There is a safety factor to a magnetic starter also: You can't accidentally leave the switch on. Anytime power is disconnected the starter/contactor disconnects. A momentary on-off switch is used to control it.
but
For a 1.5hp motor, a manual starter switch is the answer.

[wd4lc]

To follow up, I've still been using a plug strip to turn the table saw on and off. However, the way it is set up the cord is much too short and it has become inconvenient and potentially dangerous.

I decided to break open the Ryobi switch today and noticed the effects of several posts that I've read here. It is once again a contact issue. The metal part on the right was stuck. After I applied a little bit of pressure, it finally loosened up and was then able to toggle back and forth. The heads on the contacts seem to be corroded (see image below).

I guess it is still up in the air on whether it is another Ryobi switch problem or if it burned out because of something on my end. Either way, I need to get a new switch.

I've read that people file the contacts to get rid of the corrosion so that it does not stick. My switch actually worked after simply forcing that part back. Is it safe to say that If I filed the corrosion off of the contacts that eventually the same melting of the parts will happen again? If so, I'm prepared to buy the switch from Rockler even though I'm not so sure it would be my first choice.

I'm also interested in knowing if anyone has tried this foot switch from Sears?

[IMG] Uploaded with ImageShack.us[/IMG]

[LCHIEN]

I'm not really too up on this but platings on contacts are somewhat functional - I think they can resist arcing and reduce contact resistance - there are actually conflicting requirements so there are switches made for lights, resistive loads, low curent loads, ultra low current loads and motor loads. All have different types of contact plating and materials. Guys who are using residential lighting switches are probably using the wrong type of switch - these are resistive load rated. However if they work for you, power to you and if they fail, I think they under $2 bucks to replace.

So the right choice of switches is an art - switches are very different by application.
That said, filing off the contact plating will destroy any function that the plating had, provided its still there to any degree. Once you file plating off (and its only 10s of micrinches thick usually) then you are relying on the base metals which have different properties like copper will corrode, steel will rust.
Gold is usually plated reserved for low current applications. Mercury wetting is used for ultra low contact force operations.

Motors by their nature need high current contacts and the ability to resist Arcing upon opening due to motor inductive reverse EMI.

Anyway, if you file your ryobi switch it will probably work for a while then fail the same way, sooner perhaps, because you have removed the plating. I have to say at some point Ryobi cheaped out on the switch specs in a cost saving move because not all Ryobi BT3 saws have this problem, just some vintages. Probably when they were trying to get the saw down to a $300 price point.

I will say this - the amount of arcing is directly proportional to the amount of current flowing when the switch is opened (saw is shut off). Make sure you don't shut your saw off under load (high current), let it spin freely after you make a cut and remove all loading and it will be at its minimal operating current - thus having minimal arcing.

Paralleling switch contacts will halve the current in each contact and make them last longer - the Ryobi switches seem to be two pole and one pole is unused.

[wd4lc]

I'm not really too up on this but platings on contacts are somewhat functional - I think they can resist arcing and reduce contact resistance - there are actually conflicting requirements so there are switches made for lights, resistive loads, low curent loads, ultra low current loads and motor loads. All have different types of contact plating and materials. Guys who are using residential lighting switches are probably using the wrong type of switch - these are resistive load rated. However if they work for you, power to you and if they fail, I think they under $2 bucks to replace.

So the right choice of switches is an art - switches are very different by application.
That said, filing off the contact plating will destroy any function that the plating had, provided its still there to any degree. Once you file plating off (and its only 10s of micrinches thick usually) then you are relying on the base metals which have different properties like copper will corrode, steel will rust.
Gold is usually plated reserved for low current applications. Mercury wetting is used for ultra low contact force operations.

Motors by their nature need high current contacts and the ability to resist Arcing upon opening due to motor inductive reverse EMI.

Anyway, if you file your ryobi switch it will probably work for a while then fail the same way, sooner perhaps, because you have removed the plating. I have to say at some point Ryobi cheaped out on the switch specs in a cost saving move because not all Ryobi BT3 saws have this problem, just some vintages. Probably when they were trying to get the saw down to a $300 price point.

I will say this - the amount of arcing is directly proportional to the amount of current flowing when the switch is opened (saw is shut off). Make sure you don't shut your saw off under load (high current), let it spin freely after you make a cut and remove all loading and it will be at its minimal operating current - thus having minimal arcing.

Paralleling switch contacts will halve the current in each contact and make them last longer - the Ryobi switches seem to be two pole and one pole is unused.

LCHIEN, thanks for the response and interesting information. I went ahead and opted for a new switch via Rockler (used a free ship promo that ended on Sunday night). Hopefully this switch will be of better quality and/or resolve any issues that may be happening on this end. I definitely let the saw spin freely before turning it off (as well as make cuts only when the saw has hit its maximum power).

Thanks again.

[wd4lc]

An update (for anyone who comes across this thread with the same problem I had). The switch from Rockler is basically plug and play. I thought there might be some wiring involved. Instead, it has a male and female plug. I disconnected the short plug from the right side of the saw (that plugs into itself). I plugged that saw plug into the female end of the Rockler switch and then plugged the Rockler switch male plug an outlet. Works like a charm (though I can only state that from a simple testing standpoint and not over a long project).

I'm thinking about using this as a stand along switch. I might make a little portable stand for it and attach it to that instead of mounting it to the saw.

[JR]

I'm thinking about using this as a stand along switch. I might make a little portable stand for it and attach it to that instead of mounting it to the saw.

Whatever you do, you want the switch to easily come to hand and to be mounted firmly enough that when you hit it, it won't move.

JR

[dbhost]

If possible, please post pics of the completed switch replacement. I believe this would be of interest to certain vintage BT3100 owners. (my switch is fine, but my saw actually came with a spare when I bought it used... No idea why other than cosmetics...)