I'm building a router table with an Arduino driven lift.
So far I got a working prototype for the lift.
Now I need to figure out how to control power to the spindle.
I want to support the following functions:
Emergency stop for spindle
Power-on button for spindle
Power-off-button for spindle
Power switch for stepper motor (used for the lift)
The spindle has a power of 1000W.
What kind of relay do i need?
Is it enough with one relay to support the emergency stop, power-on and power-off or do I need additional components?
I want to have a separate power switch for the lift. To power the lift (and the Arduino) I use a power supply that outputs 24V 2.2A. I suppose I should be able to connect that directly through the switch, right? Or would I need additional components?
What is the difference between Emergency OFF and Power OFF for the router?
When I had a router table, I used a step-on air switch as my emergency OFF. They call them dead man switches; you might google how that name arrived.
As a former electrician with industrial experience and a little elevator design experience, I can tell you emergency switches should NOT be done with logic devices but hard-wired into the main power line of the device using a mechanical switch. Adding an Arduino adds more points of failure and, in this case, a point of failure resulting in the router motor NOT turning off. KISS.
The Arduino can be used to control the router lift. If you are like many others and think a plunge router is the way to go, ask a router design engineer. The mechanism is not designed for those forces. But go ahead; they love selling you guys more new routers. NOTE, I have been away from that stuff for a decade or more, so maybe they make 'liftable' plunge routers now.
Maybe they are the same, but I want one of them red proper emergency buttons. It should be easy to access in case of emergency. For day to day usage I rather use another button.
Hard-wiring is the way I want to go. Sorry if I made it sound like I wanted it in another way.
I’m asking for help finding the right components to do a proper hard-wiring. The spindle is 1000W and that’s too much for the emergency stop buttons I find where I live. I think I need a relay.
I read that a 1000W spindle might pull 20-30A when starting, if that’s true I still need a relay, right? It’s a Mafell FM 1000, I did not find any info about startup power.
All power ratings are thermal ratings, that is to say how much heat the item can dissipate in normal operation before heat degrades the item. A brief increase in current will not cause a sudden jump in temperature, because everything has a mass which takes time to heat up.
What is the brand and model of the router? Remember, routers are labelled with peak wattage. For an emergency switch, all you care about is amps, assuming it's the right voltage.
It uses 4A at most. Ignore wattage; it's volt amps that matter. I guarantee you I can go to my local store and buy an emergency switch that will work. Adding a relay DEFEATS it's used as an emergency power off since the event causing the emergency could weld the relay contacts together. One of those big red mushroom switches is often by the door of an entire shop, controlling a dozen pieces of machinery; it will handle your little router with no problem. My router was 3.25HP, which is 2,437.5 Watts and 20 amps at 120VAC. Here is the link to my switch that controlled a router 2.5x the power of yours, AND because you are 240V, you have 1/2 the amps again, so 15 /2 is 7.5 and / 2 is 3.75, pretty close to the 4A I guestimated earlier. https://www.leevalley.com/en-ca/shop/tools/power-tool-accessories/safety/30049-air-actuated-foot-switches
Indeed, those big shops that have OSHA standards and a bunch of machines use a contactor, and that is what the big red mushroom switch is connected to.
You, on the other hand, are putting a small handheld router in a table for some reason. Normal table routers are 3.5HP, and yours is 1.25HP. I worry you will destroy that router fairly quickly.
Train is better than bus.
If you only need to manually control on/off that router, switch is better and safer and cheaper than relay and contactor. And >4A 240VAC switches are likely available in every country on this planet.
Thanks for your input. I did some more reading and learned that like you say a brief inrush won’t instantly burn components. However it can cause contact wear, arcing, or tripping of breakers over time.
It seems all the estop switches that are rated for >5A are in a yellow box, I suspect they have a contactor built-in. Thanks for all the help, it really spurred me to learn more on the subject.
I really wonder where you are getting your advice from. I very much doubt those are significant factors for the device in question. It's sold as a household product... it plugs into regular house wiring and outlets. It's not going to damage it.
There do seem to be some hobbies where they just like to spend money on kit even if it is not necessary. A little bit of folklore gets passed around "use a contactor it has all these theoretical advantages!" then everyone feels justified spending the extra money. Possibly, some of the folklore is started by people selling kit.
Anyway, it seems kinda pointless asking our advice here, then saying "no this other forum says something different".
Hey man, I really appreciate all tips I can get. It’s just that when you read contradictory info I want to dig deeper and found out what’s going on.
But if you dig into the datasheets only a handful got the >5A rating (my spindle has 4.6A rating I’ve since learned. The ones with a >5A rating are in a yellow box and are more expensive, they probably have a contactor built-in. So when you say I don’t need a contactor it probably only half the truth because what you are saying is buy a boxed estop and save you some trouble because it has a contactor built-in.
