Denford Software & Machines

I looked at the control panel a couple of days ago . Not a very nice looking item is it ? The box controls a 3HP rated Teco VFD
I downloaded a copy of the Teco E2 manual from Drivesdirect website the VFD supplier.
After a bit of studying and checking the spec a plan was formed. 1. New Tach . so Ebay time .. Blue Led tach with sensor... https://www.ebay.co.uk/itm/Blue-4-Digita ... SwnNBXY3Xj
2. new switches umm what do I need ..
After what seemed hours searching the Bay for components and watching loads of items I decided it was time to get something drawn up, a wiring schematic and some setout plan.

The guts of the 3 phase oiginal wiring were gone replaced with lengths of 2.5mm mains cable, stripped out to 4 seperate strands feeding the motor from the VFD .. TUT TUT.. The only other wiring is the control wire for the 10k pot and switch in the control box which was alarm cable ..( control box and cable Supplied by Drives direct )


The VFD control box that was fitted into the original controls housing as in the picture above only controls the speed through frequency steps with a 10k potentiometer and a 3 position on off on switch . for Fwd stop reverse control .
The VS pulley setup had been converted to manual operation ... I'll come back to that some other time. So rather than remove a working unit I opted to include a new drive system for pulley adjustment . Thus more control components to consider.

Things started to get out of control with bits of paper so I dug out a copy of Circuit Wizard that I have ..
If anyone is considering anelectrical project give Circuit Wizard a look .. It allows circuit testing and design virtually.

https://www.new-wave-concepts.com/ed/circuit.html. This is what i started . everything is usable when running project virtually, such as buttons leds and motors . You can even read voltages pulses , use a virtual ossiloscope .. loads of stuff I can go on and on about how good it is . Try it it's available for free after registering . I have registered previously and saved a copy of the exe to disc.

I have ordered 99% of the components needed to build the control panel and fully rewire the lathe .


I have include 2 off 22mm panel mount momentary stop /start switches with a simple DPDT relay latching circuit ,
This allows led indicator lights for start stop without current draw from the VFD 12v control line which is approx 100ma max draw.
3 small 3mm leds worth @ 30ma each so no good .

I designed the system so the 12v VFD control is only ever a signal never supply. You can opt for external 24v supply to the VFD for control,
but with having some Din rail mounted 12v coil relays and switches knocking about,
as well as needing to purchase a 30amp plus 12v DC supply for the VS pulley speed adjustment motor ,
I wasn't splashing out on other components rated 24v or wasting anymore space with a extra PSU.

The Fwd Rev selection is done via a 2 position rotary latching switch 22mm panel type industrial controlling another DPDT relay with led direction indication of spindle direction.

Jog button as been include , Another 22mm momentary switch , ( not a necessity but nice to have jog function for just chuck tightening in low ratios )

Estop . Latching switch . Didn't have any Estop at all before .Daft

The new pilot motor replacement for the VS pulleys is a car wiper motor rated 20 amps running 30 amp fuse protected .
I ordered a 40 amp 12v PSU to give some safe area as I have ordered PSU's before and they never run at rated spec without issues so
I always get 125% rating of what I need.
Control for only short periods of use was needed using momentary switching to select direction .
A simple relay polarity changeover circuit did this again with a DPDT relay . Allowing direction leds as per the original but ,
I opted for one of these instead of the traditional joystick control as it's in keeping with the rest of the buttons .
https://www.ebay.co.uk/itm/121707773809? ... EBIDX%3AIT The potentiometer for frequency adjustment will remain the same but with a different dial ,
I will test a 2.5 multiturn pot I have first to see if it allows more precise rpm control.

I ordered 2 waterproof rocker switches with backlight when on for the coolant pump and 12v lighting .
The lighting will include the standard fitment 12v halogen lamp which I have a couple of from other lathes all the same .
The light will be retrofitted led . I have some nice 3 watt Lumistar leds with aluminium heatsink mounts fitted.
These will go nice inside the lamp to replace the original bulb holder . I will post the conversion later I need to build a dimming regulated driver first.
might as well have dimming option .

I used a 3/4 turn pot on my last vfd install and I was very happy with the response.