Adding a foot switch to Disk Grinder (3 phase)

Patrice Lemée

Patrice Lemée

Joined
Aug 13, 2002
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5,703
Starting a separate thread about this. Here goes:

I have a 3 phase powered disk grinder running off a VFD with remote controls near the grinder. I need an on-off foot switch. Should be easy (relatively speaking) to wire something but when it comes to electrical stuff I am lost. As you can see from my control box there is a on/off/on starting/reversing switch in there. I have some cat5 cable and a couple other switches (not sure which one I should use). I am thinking that it should be possible to wire a on/off switch to that one and then make a receptacle for it located near the floor. The thig is I have no idea how to do this. The Count posted some info in the other thread:

The VFD is alreads a switch & you can use it to control.
Running the VFD steady and cutting off it's output is probably bad.
http://www.twmi.com/products/control...nual_04_05.pdf
Page 17 wiring manual
I expect that by reading the diagram...test it for yourself to be sure
screw 3 connected to screw 5, with a footswitch in between- will give you pulse forward.
screw 4 connected to screw 5, with a footswitch in between- will give you pulse reverse
combine those
putting the middle pin of a spdt switch to screw 5,
the outers terminals of the spdt to 3 and 4
and your foot switch between screw 5 and that spdt switch
seems right, anybody else ?
clear as mud ?
Click to expand...

There was also something about using a foot switch for 110 but gutting it. I have one but the other option seems a lot simpler. (and would let me use that foot switch somewhere else.

So as you can see, mud would actually be much clearer to my electrically challenge self.
Here are a few pics of what I have.

switch1.jpg


switch2.jpg


switch3.jpg


switch4.jpg


Any input greatly appreciated!
 
I use CAT5 for speaker wires in my computer shop :P I'm sorry I can't help with the question though.
 
I'm writing this all from reading the manual & my experience with the KBAC27D
Do your own testing.


Original page 17 of your Teco FM 50 controller
FM50page17wiringdiagram.gif


The VFD controller already has remote ""Multi Function Inputs"

I think the simplest way to do this is by attaching a dedicated foot-switch to the VFD.
It will let you use it on belt sander, disc sander, whatever you attached to the VFD.

Just buy a premade one like this & put your own wire in it- remove any outlets if it has any.
Make sure it's "momentary" and not press on, press off
Billy%20Switch.jpg

Lots of sources new and used (guitar, keyboard and electronic music applications MIDI is a good keyword to search)
I can buy power foot-switches at Busy Bee in Canada.


CAT 5 is a decent choice of wire.
You could even wire up pairs of wires as conductors to increase reliability.
I would tend to want to use stranded wire.


This is what I had in mind.

One footswitch, one SPDT switch mounted in the controller enclosure box - to give you the forward - reverse

FM50page17wiringdiagram-EDITING.gif



Again this is assuming you can trust the manual.
 
Last edited:
Thanks Sam, it's getting clearer.
How about something like this?

Splitting the signal coming from the VFD and using a single throw switch to control that at the floor level.

switch5.jpeg
 
One thing I have trouble with, if anyone has ideas:

Connectors for mounting the footswitch to the controller box

I'm looking for a nice panel mounted female
or inline connectors

Something handy, with safety clips that won't just pull out.
made to some sort of universal standard that I can buy 5, 10 years from now.

I think audio connectors are made for very low current carrying - and they don't give that safety against pull out.
 
You can use industrial photo eye cords that are female ,male connections but they are totally enclosed they are dust proof and have a ring that screws on the outlet on control box .You can get different lengths
 
You guys are muddying the water! ;)

Here are a few pics of the temporary hook-up I did and lo and behold, it works. Before I build a box and solder the switch in, do any of you see something wrong with this?

switch6.jpeg


switch7.jpeg
 
Count, you have it just right.
Patrice, I think you understand the function ,now.

The simplest way to attach and detach the foot switch is to install a mini-phono or a 1/4" phono plug in the cabinet. Wire the jack to the switch as the count showed. and put a matching plug on the foot switch. Many foot switches already come with a 1/4" phono plug.
 
bladsmth said:
Count, you have it just right.
Patrice, I think you understand the function ,now.

The simplest way to attach and detach the foot switch is to install a mini-phono or a 1/4" phono plug in the cabinet.
Wire the jack to the switch as the count showed. and put a matching plug on the foot switch.
Many foot switches already come with a 1/4" phono plug.
Click to expand...

I did think of that, but someone mentioned to me that the current capacity of a phono plug is insufficient.

I don't know the values, but it raised doubt.
 
If the switch is only a control switch ( vs a load/power switch) then the current will be in milliamperes. Most control circuits are 12V or less at 500 milliamps or less. Well below the current capacity of a 1/4" phono plug. If really concerned, use a DC power plug and socket.

The reason you don't use a 1/4" phono plug/jack for power/load circuits is mainly that the contacts may short or arc upon insertion of the plug into the jack ( especially if a stereo plug is accidentally inserted). This can be a bad thing when 120VAC is on those contacts.

When using a phono jack (and plug) to handle a signal or switching voltage ( as in this foot switch) use non-shorting (not switched) mono jack and a mono plug. Since the foot switch is a control device, it should be plugged in while the device is turned off. Random spikes and such are not good for VFDs. That is why you should not turn a VFD on and off with the main power input.
 
Well I finally installed the switch in the above picture and it works great. I might swing by the local electronics place next week to see if they have something more like a click-on/click-off type of switch but the toggle switch works good enough if I don't find anything else. I did not want to use the foot switch I had since you need to have your foot on it for it to turn on. And also I can use it elsewhere and it seemed like waste to gut it if I could find another option.

I'll let you know what I find but this is already working great.

Thanks for all your help guys. :thumbup:
 
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