# Signal light from VFD?



## Mister Ed (May 14, 2017)

I recently installed a TECO LMS510 VFD for my new Logan lathe. I placed a 220 on/off switch before the VFD to cut its power when not in use. Only one problem, I have the VFD out of site and more than half the time I don't remember to power it down when finished.

So, the question is, can I tap into the 12volt control power from the VFD to run a small 12 volt lamp when the VFD is powered on? Or would that cause issues? I am already tapped into that power source for the Forward/Stop & Reverse/Stop functionality.


----------



## markba633csi (May 14, 2017)

You should be able to easily run an LED indicator or two. Doesn't the unit have a dedicated low voltage output just for that purpose?  
Mark S.


----------



## wildo (May 15, 2017)

I'm driving a 12V relay using the aux line on my Teco VFD. Depending on what your light power consumption is, you might need a relay as well. But yes, the idea is totally doable. (And yes, I always forget to power down my three VFDs as well!)


----------



## JimDawson (May 15, 2017)

Mister Ed said:


> I recently installed a TECO LMS510 VFD for my new Logan lathe. I placed a 220 on/off switch before the VFD to cut its power when not in use. Only one problem, I have the VFD out of site and more than half the time I don't remember to power it down when finished.
> 
> So, the question is, can I tap into the 12volt control power from the VFD to run a small 12 volt lamp when the VFD is powered on? Or would that cause issues? I am already tapped into that power source for the Forward/Stop & Reverse/Stop functionality.



Be careful that 12V supply is only rated at 40ma max current output.  It should only be used for the control wiring.

The better way is to use the aux relay, and program it to turn on anytime the drive is powered up.  This would require a power source for the indicator lamp that is external to the drive.  You could also wire in a 240V lamp across the VFD input terminals

Or, do what I do and leave the VFDs powered up all the time.   Keeps them warm & dry.


----------



## wildo (May 15, 2017)

JimDawson said:


> You could also wire in a 240V lamp across the VFD input terminals



I think this really is the far better solution. Easy, simple, no fuss.


----------



## mksj (May 15, 2017)

Some VFDs can supply a bit more from their terminal input supply, but the maximum current capacity for this VFD for the  12V terminals is 20mA. LEDS run about 0.3W or around 25-30mA on 12V at their best. You can purchase inexpensive 12 or 24VDC power supplies and wire the power supply to the VFD input power, this can power an indicator light, low voltage lighting for the machine, a tach. etc. This is what I do for most of my system builds. The VFD's multi function relay is rated at 1A at 250VAC or 30VDC, so could be used as a trigger for an indicator, but you still need a power source.


----------



## RJSakowski (May 15, 2017)

The current draw by an LED depends upon the current limiting resistor.  They will run comfortably on less than a ma if necessary.  A 2 kohm resistor in series with the LED will limit the current to about 2ma on a 12 volt supply.  A 390 ohm resistor will require about 10 ma and give you a brighter light.


----------



## CluelessNewB (May 15, 2017)

240V indicator lamps are readily available for less than $10.   You can even get some LED versions shipped free from China for less that $5 on Ebay!


----------



## tq60 (May 15, 2017)

Exactly what we have...

Vfd installed in box under lathe with large plug in cord that we leave unplugged...usually.

Used factory drum switch to control vfd.

Under chip tray is a pot for speed control and a 20 amp light switch double pole aa main cutoff for the 220 line in.

A 240 vac neon pilot panel lamp is installed in the drum switch that indicates power into the unit.

Fed via a pair of wires fused at the input to vfd.

A bit hard to find but available at most well stocked supply places.


Sent from my SAMSUNG-SGH-I337Z using Tapatalk


----------



## rgray (May 15, 2017)

I use a power strip on a couple of mine. No unplugging and plugging in that way. Just turn the switch on or off.
They are small vfd's so that works for me. Would need a better quality for a larger vfd.
I moved my mill recently ...I used to use a power strip for the 110 volt items. After moving it I wired it with switched outlets. Throw one switch and the light, dro, 24v power for knee lift, 110v for coolant pump, and 110v power to x axis are all either on or off.
I don't see any reason you can't use a 110v lamp as your indicator. I use a 110v as a pilot light on my 3 phase surface grinder to remind me that the rpc is running and to turn it off when done.


----------



## Mister Ed (May 15, 2017)

Thanks folks. I will look into a 240vac indicator of some type. I didn't even realize they existed.


----------

