Hi rstermer

I do like the dead man type,,once your foot is off the machine is off,most of the time you are wanting to move back away for the machine,I use them on the scroll saw,band saw,router table...and you always have the plug or the main power switch to over ride it so you don't just step on it in error,,

http://ptreeusa.com/routerControls.htm

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Hi rstermer


Router Controls

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Grainger has the same switches for a lot less. My own preference is the on/off version, since it allows me to shift my position, but still can be shut off without removing my hands from the job.

 

The only reason I don't use a deadman is I move too much. I'm always adjusting my stance and quite often when duplicating historic molding and trim I have the stock between the bit and fence.
In my case accidentally stopping the router might create more problems than the switch is worth.

 

I am having an NVR switch. Mounted on strong magnets, to stick in 2 or 3 places on/under the table, with a push off floor switch. Both will take 200 watts. The foot switch will break the circuit. I will have the router Elu177/Dewalt 625ek on all the time. Switching on from the conveniently placed NVR switch.

 

Hi MIke- Thanks for your reply. What is an "NVR" switch?
Thanks,
RAS

 

A light switch has served me well for a long time. I just mounted it in a box and ran a pigtail off it to plug the router into. KISS is the way to do things.

 

hey Mike,

i may be too inexperienced to have an opinion, but i will have to agree with your light switch method. its working for me and for a simpleminded person like me, i like the kiss method ,lol well also, im a little on the cheap side

 

I like the "constant on" foot witch. Like Ronald, I move my feet a lot.

 

The best solution is to have an emergency stop kill switch. The idea is to be able to quickly shut down when there is a problem. I use one of Rocklers first generation On/Off boxes on one table, which has a recessed start button and an easily available stop button exposed. The newer paddle type is a better choice. A standard wall switch is fine as long as it is easy to get to. Remember, this is for emergency stop situations only. You still need to use the router switch and unplug when making adjustments for safety.

 

No Volt Release Switch.

 

I don't recall what channel I saw it on about a year or more ago. I only caught the end of it show pitch whatever it was. I'm not sure exactly what it was, I never saw the device only the results comparing one TS with and one without. I'm guessing it was a sort of kill switch/break.

Here's the thing, the device sensed either the moisture or the galvanic response in tissue/meat even processed meat. Which resulted in an almost instantaneous breaking of the blade. The test used hot dogs.

 

That is the Sawstop table saw.

 

Now if only my laser cutter worked like that. Seeing debris on the cutting table, over-ride defeated by 2 magnets, just a quick flick to clear the debris, results in 2 short cauterised fingers.

 

Thanks Myk, I'd been thinking about that thing a couple times and wondered if it was something you could attach to any TS. After seeing the little demo on their site, It seems obvious it's still too big to apply to routers.

A wrecked blade and, (replaceable) brake is well worth a finger any day eh!

 

A NVR switch is designed so that if the power goes out while you are using whatever is switched, and you forget to turn it off before the power comes back on, the tools will not automatically turned back on.

Essentially, pressing the "on" button mangetically latches a relay. When the power goes off, it opens the switch. When it comes back on, you must press the NVR "on" button to restart the tool.

In America they're commonly called a magnetic switch. It's a great safety device.

I've attached one vendors web page. Here's a link to the web page (one source). Note that only the ones labeled "magnetic switch" apply.

Grizzly.com® -- Product Categories

Jim

 

Grizzly specs their switches very conservatively, 16 amps but only 0.5 horsepower. My PC 7539 router draws 15 amps, so would meet that spec, but is listed as a 3.25 HP router, whereas the switch is only rated for 0.5 HP. They must want to make sure they don't have any warranty claims!

In a perfect world, assuming the power factor and motor efficency are both 1 that switch should be good for;

HP= VA/746 = (110 x 16)/746 = 2.35 HP

so they have really derated it to accomodate motor inefficency and power factor.

Or, looking at it another way, maybe PC's 3.25 HP motor delivers 3.25 peak hp, but its operating hp output is a lot lower, so maybe PC lists current draw based on normal operating conditions but advertises their motor HP based on peak production, a marketing gimmick. Assuming PF and eff=1, the current draw for a 3.25 HP motor at 110V should be;

A = HP x 746/V = 3.25 x 746/110 = 22 Amps +/-

so there is apparantly an inconsistency. Its been a very long time since I studied this stuff, so maybe I'm not remembering all the details, and that, of course, is where the devil resides.


rstermer

 

An article on ratings, HP, and amp draw regarding power tools:Playing the numbers: performance standards would benefit toolmakers as well as tool buyers. So why does the industry continue to shirk them? | Tools of the Trade | Find Articles at BNET .

Cliff's notes:There is little correlation between a tools amp rating and HP rating or actual force to the work.

For myself, I've always used the formula 1 1/2 x assumed total draw of the circuit. Total draw would be the maximum draw of the device being powered and the resistance of conductors (wire, switches, capacitors, etc.). In the case of a 12-15 amp rating of a router, a circuit using a 20 amp switch should be adequate. In fact, that is the rating of the single pole switch on my table, 20 amps.

 

Thanks for posting that article. It confirms my thinking, PC is listing the power output of their motor on a peak basis, whereas the current draw is spec'd at what the motor can draw and operate on a continuous basis. What the actual shaft output of the motor is (which includes internal inefficiencies) is yet another question, my thought is that winding, bearing, air moving and other losses might amount to another 10-15%, so the shaft horsepower of the motor might really be somewhere around 2 HP, which is a whale of a difference when compared to the 3.25 HP advertised horsepower rating. That said, it's still a hoss, and quite scary if not treated with respect.

rstermer

 

I do not remember the source of the article I saw but it claimed the actual hp of the Bosch 1619 and PC 7518 fell very close to 2.75 hp. The same article mentioned that the Bosch 1617 measured 2.15 hp, not such a big difference for the price. Even so, to play it safe any router rated at 3-1/4 hp should be run on a 20 amp circuit or with components rated for 20 amps.

 

If it was really 2.75 HP, the minimum current the motor would draw would be

A= HP x 746/v = 2.75 x 746/110 = 18.65 Amps,

which is more than the continuous duty rating of 15 amps, so that article was probably wrong, maybe more advertising hype.

rstermer

 

rstermer,

And that's not including the efficiency. While a horsepower is indeed 746 watts, a good rule of thumb is 1 horsepower = 1,000 watts to account for this. With 1000 watts/120 volts it comes out more like 8.33 Amps per horsepower. To get 2.75 horsepower would require 22.9 Amps at 110V (2.75 * 8.33).

To size the breaker for 2.75hp, the NEC only permits you to use up to 80% of that current for a planned load. Therefore you would need a breaker 22.9 / .8 = 28.6 amps. Since such a thing does not exist, you would need to round up to a 30 amp breaker. This is not in your typical house.

The efficiency is also why people say that a 1.5 true hp motor is all you can run off of a 20 amp breaker. Using my rule of thumb, a 1.5hp @ 1,000 watts per horsepower and 120 volts you get 15.6 amps, which is close to the maximum of 20A * .8 = 16 amps you can draw from a 20 amp breaker.

Jim
EE & wanna-be woodworker

 

Mike- Very good points. I didn't include the power factor either.

I've run a lot of wood through my PC 7539 "3.25 HP" router, all on a 20 amp circuit, and have never tripped the breaker when running the router alone, so the actual average power output of that motor is probably, as you say, less than 1.5 HP. Usually, I can run the router and my "1.5 HP" dust collector on the same circuit and not trip the breaker. I conclude no useful information is conveyed by router manufacturers advertised horsepower ratings, its all a marketing gimmack. Thanks again for your post.

rstermer
ME & wanna-be woodworker

 

rstermer,

Actually, there's some good information in what they give, if you do not try to read too much into it. Routers use universal motors which, under load, draw more current as the load increases. I've heard reports (not verified) that the locked rotor current on the 3hp class of routers can exceed 80 amps. The life expectancy (due to overheating) wouldn't be very long. Somewhere between there and "no load", it delivers its maximum "work". They can use marketing weasel-words in their declaration of horsepower but, assuming its UL (or CSA-UA or several others) listed (and they are, or are supposed to be) there are strict listing requirements what they can say on current draw. They are required (if listed) to place a nameplate on the router indicating its tested rating. For example, my PC 7518 indicated 120V~ 60Hz, 15A. This indicates that it is designed to protect the unit from damage at 15amps.

I wouldn't consider the difference between 12 amps and 12.1 amps to be significant, as it can be lost in motor efficiency but the difference between 12amps and 15 amps (in real world situations) is significant.

Further, with the marketing weasels being what they are, 15 amps is the maximum vendors *want* to claim, unless they were to back up far more. This is not only because the informed will know that's near the maximum you can run on a 20 amp circuit but also to make it appealing to all of the uninformed out there who only have 15 amp fuses/breakers and want the biggest they can get.

Will it run on a 15amp breaker? Yes, as long as the inrush from turning it on does not pop the breaker (such as starting up with a large heavy bit) and they don't bog it down. Does the conservative NEC approve it? No.

This same gimic is how the weasels claim to have a 6hp shop vac. This is very deceiving. They can claim it because they know the fan will only draw so much torque at the motors speed. Knowing the torque, one could figure out the true horsepower delivered. Think about it, if you were to hook the fan to a real 10hp motor, running at the same RPM, it would still require the same torque. The amperage would be higher due to the energy required to turn over that larger motor but it would be no where near the FLA (full load amperage) rating.

 

On a related topic, on Monday I"m ordering a new table saw. It is a cabinet saw that is available with a 3hp or 5hp motor. I've debated which to buy, as the 5hp is priced only 6% higher than the 3. I've decided to order the 5hp (assuming they are available for delivery in a reasonable time) since the 5hp will not have to work as hard when I'm cutting 8/4 maple. Would a 3hp cut it? Yes. For me its just a personal preference as I recognize that less wear occurs on the motor when it is lightly (for its HP) loaded. If it was 20% higher, I'd surely go for the 3hp unit. This way I konw I will never look back and wish I had.

Jim

 

I found the knee-height paddle-off switch the most effective, movable from one side of the table to the other. it can serve as a safety switch since it only takes a quick knee tap and the power is cut. I don't like deadmen. Table use implies moving around, something you cannot do with your foot anchored to the floor. Also, the deadman will be far too dangerous since it won't allow you to follow the cut closely. Having a router trip off is just as dangerous as one uncontrolled. BusyBee sells a big clunky paddle switch. The thing is big. Take a look and you should find the same thing from a US supplier. The only addition that I would suggest is that you add a simultaneous switch, one that turns on the vacuum when power is applied to the router.

Hope this helps

Allthunbs

 

Rockler router paddle switch

I have the new Rockler paddle switch connected to my router table. It is conveniently located and easy to shut off. I'm not concerned if the power goes out, because if it does while I am working at the router table, I'm sure that I'll turn it off before I leave. The switch is relatively inexpensive and pre-wired with a 2' female plug (to router) and a 10' male plug (to outlet). Took me 5 minutes to mount to my router table and plug it in.

 

Hi Ho: Switch looks good. What seems to be missing from this thread is that the power rating for motors has little to do with the power consumption. All routers I know of consume less than 15 amps. The reason is that people want to use a 15 amp circuit to power them. This includes includes the 3.25 hp jobs that according to ohms law would use more than 18 amps.

However the thread started by asking about switch ratings. The starting current for motors can momentarily be as high a four times the average or run current. The switch contacts will have to handle this current spike and the contacts will be pitted over time. However, even if a 15 amp switch that is rated for only 0.5 hp or whatever, even with a 3.25 hp router , will probably be just fine in the kind of use we give it. And if it isn't, routers don't run by themselves, so the worst that will happen is that the switch will need to be replaced at under $10. Not a big deal.

Dirk

 

I have used the simple on/off switches for over 30 years, have never had to replace one. Nearly all my larger machines are 220V, on those I have the magnetic type. What I wanted to add is PLEASE don't use the $1.00 switches that HD and others sell. Those are all 15amp. Expect to pay $8-10 for a heavy duty hospital Grade 20 amp. I also prefer to use the DPDT (Double pole, double throw) Last time I got one they were about $12 from HD. I did buy a couple of the safety paddle switches to use on my router tables. Just need to find the time to install them. Most of us work alone in our shops, so always be safe!!!
Harry