# Magnetic On & Off Switch General Tablesaw 350



## CrowDennis (Jan 19, 2016)

Does anyone know where I can get a new magnetic on & off switch for a 20 year old General Table saw model 350. This machine has served me faithfully the entire time. This machine is NOT a General International. We have contacted a couple companies but everyone ends up going to Canada and the wait is over 2 months!! 
Do you know if another companies switch would be compatible with my machine? For example - Grizzly. 
My first post - hope you can help. TY


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## Steve Neul (Sep 2, 2011)

A magnetic switch doesn't have to be model specific to the saw. Any electrical supply should be able to fix you up with a switch. They are even listed on ebay. You just have to select the right voltage and amperage rating for the saw. 

A magnetic switch is a safety device mostly needed in a factory setting. The way it works is if there is a power failure the saw won't just come on when the power does. For an individual working by themselves in their garage it isn't quite as helpful. The saw could be wired with a toggle switch similar to a light switch.


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## klassenl (Jan 2, 2011)

Or talk to your local electrician.


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## Shop_Rat (Dec 22, 2015)

If that saw truly has a 3 horsepower motor on it, I would want the starter. At 115 volts it would draw 34 amps; at 230 volts it would draw 17. Locked rotor starting current is usually around seven times the full load amperage (FLA) of the motor. Starters (contactors) have beefy contacts that can take repeated arcing during starting and stopping.

But as Steve has said, a starter doesn't need to be brand specific. It simply needs to fit in the enclosure and be rated for the load. And they are not normally expensive. Here's a quickie I found at Amazon. 

http://www.amazon.com/Magnetic-Star...&qid=1453253390&sr=8-2&keywords=motor+starter

Just insure that whatever you get that it's rated for the horsepower and has a coil voltage that is compatible. I assume you are using 240 volts, so if you don't have a neutral available, find a starter with a 240 volt coil.


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## woodnthings (Jan 24, 2009)

*This switch*

This switch meets your requirements:
http://www.grizzly.com/products/Magnetic-Switch-Single-Phase-220V-Only-3HP-21-25A/T24101

I had a mag switch fail on my 3 Hp bandsaw and I replaced with a double pole 220 V non-magnetic switch. I didn't need the safety aspect of the mag switch in my home shop.


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## Steve Neul (Sep 2, 2011)

This switch should also work. http://www.zoro.com/leviton-wall-sw...gclid=CNmz0Kynt8oCFQ2HaQodnCUNOw&gclsrc=aw.ds


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## GeorgeC (Jul 30, 2008)

Shop_Rat said:


> If that saw truly has a 3 horsepower motor on it, I would want the starter. At 115 volts it would draw 34 amps; at 230 volts it would draw 17. Locked rotor starting current is usually around seven times the full load amperage (FLA) of the motor. Starters (contactors) have beefy contacts that can take repeated arcing during starting and stopping.
> 
> But as Steve has said, a starter doesn't need to be brand specific. It simply needs to fit in the enclosure and be rated for the load. And they are not normally expensive. Here's a quickie I found at Amazon.
> 
> ...


I think the discussion is about an on/off switch that is magnetically latched. Unlatches when power is lost.

George


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## Steve Neul (Sep 2, 2011)

GeorgeC said:


> I think the discussion is about an on/off switch that is magnetically latched. Unlatches when power is lost.
> 
> George


A lot of folks buy a saw that comes with a magnetic switch and when they replace it think they have to replace it with a magnetic switch. Depending on their situation it may not be needed. The saw certainly doesn't know the difference. If they have a business with employees then the switch certainly should be a magnetic switch.


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## Shop_Rat (Dec 22, 2015)

GeorgeC said:


> I think the discussion is about an on/off switch that is magnetically latched. Unlatches when power is lost.
> George


That's what I posted; a magnetic starter. A mag contactor can be wired either way. If it has an auxiliary contact, it can be wired to momentary contact push buttons and, indeed the motor will not re-start on power loss and re-energization. However, many many contactors are wired with maintained contact switches that can absolutely re-start when the power comes back on.

Like I stated before, contactors are designed for large current surges when starting from locked rotor. They have large contact surface areas and latch quite tightly and quickly to minimize the arc intensity under seven times the full load of the motor. OP did not tell us the horsepower of his saw. I looked up the model number he gave and have answered the question according to a three horsepower load. There are very few toggle switches that are rated for three HP.

If you have a larger motor that has a starter installed on it, it is usually simply smart to keep it that way. It was designed for the load it will incur. That said, there are many alternatives to the brand that came on the machine, and many of them are quite economical.


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## TimPa (Jan 27, 2010)

a "motor starter" is a magnetic switch - yes. but a very important feature is that it contains (over-current) protection circuitry for the motor. some (smaller) motors have the thermal protection built-in in the form of a resettable push button on the motor.

a motor will "die trying". in other words, if a motor is allowed to consume as much current as it wants, it will burn itself up if the rotor is ever stalled (locked, jammed, etc.), because the field windings have more current passing through them than they are rated for.

replacing a starter with a switch or contactor will lose that motor protection. if it came with a starter, you should put one back on. if it just has a magnetic switch, then the overprotection may be in the motor or doesn't exist on board (your circuit breaker may if on an appropriately sized circuit).

op - you need to tell us motor specs (voltage, phase, current) and we can help you find a replacement switch or starter. a pic of the switch or starter will help.


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## Shop_Rat (Dec 22, 2015)

Though I do not suggest to anyone to alter their machinery controls, I do not often use overload protection in equipment in which I am in constant control. If I'm hovering over the tool, I have the ability to shut it off in a moments notice, such as with stalling a saw blade or a drill bit. 

I do however, use overload protection on machinery like, say, my 7 1/2 horsepower air compressor. I do not constantly monitor it, so it could easily lock the motor rotor and I wouldn't know it until it was way too late.

Again, I do not ever suggest this practice to clients, and I'm not suggesting that any of you do this either. As a licensed and insured master electrician, it would be unethical to suggest defeating any safety device (if it was designed with overloads, insurance companies qualify them as a safety), and it could open up personal as well as professional liabilities. 

Like TimPa said, let someone know of your machine specs, and you'll have a host of correct solutions very quickly.


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