By continuing to use this site, you agree to our use of cookies. Find out more
Forum sponsored by:
Forum sponsored by Allendale Jan 24th

Myford Super 7 VFD Controls & Clutch Switch

All Topics | Latest Posts

Search for:  in Thread Title in  
Nick Hulme10/05/2018 11:14:22
743 forum posts
37 photos

This is the VFD control box, mounting position is undecided as yet, adding the clutch switch makes position less critical.


This next bit is a temporary kludge with stuff that was lying around but after seeing my friend's M300 it's been niggling me that I have to use a switch to cut motor power.


These show them working -

- Nick

Pete Rimmer12/05/2018 20:35:04
774 forum posts
50 photos

What is the microswitch for Nick? An electrical interlock for the belt lever?

Neil Lickfold12/05/2018 23:03:32
628 forum posts
102 photos

Hi Nick,

What is making that high pitch noise in the video's ?

Is that why you want the motor turned off ? or is there some other reason for the constant start stop of the motor?

Yeah the forward reverse and the breaking rate control and the acceleration rate control is just great with a VFD, and the programmed settings that can be made really is awesome. Mine is just box on the wall above the lathe, with the original on off forward reverse switch, is just doing the remote feed off the controller. So the original switch does on forwards/ Off/ On Reverse. The variable aspect is on the adjuster pot mounted on the front cover of the box. Then I have a micro switch that I attach with a magnet , that when activated, turns off the forward control. Then when I switch to reverse, it starts up and runs back. I use this for my thread depth stop when screw cutting inside parts. And now also use it for outer threads as well. Takes away the guess of when to stop. I don't run my S7any quicker than the 60hz in low drive top belt, so something like 700 rpm is the max I run. But the spindle is adjusted to give me the lowest possible error of roundness and spindle movement for trimming my pistons.


Nick Hulme13/05/2018 20:08:38
743 forum posts
37 photos

The whine is just ringing, I'll tune the VFD modulation frequency at some point but it's the camera mic gain making it seem louder than it is.
The reason to have the motor off when the lathe isn't cutting is that most lathes designed as 3 phase machines work that way, the only reason for running a motor for more of the time is if it's a single phase motor with start windings and the associated lower starting torque and risk of start winding overheat with constant starts & stops.

Nick Hulme18/05/2018 14:59:01
743 forum posts
37 photos
Posted by Pete Rimmer on 12/05/2018 20:35:04:

What is the microswitch for Nick? An electrical interlock for the belt lever?

Sorry Pete, I missed that.
No, it's on the clutch lever, it stops the motor at the end of travel just after the clutch is out and starts the motor again as you bring the lever away from it's end of travel just before the clutch is in, there is now an interlock switch on the spindle lock pin though.

Since the video I've also changed the VFD modulation frequency to eliminate the audible ringing.

All Topics | Latest Posts

Please login to post a reply.

Magazine Locator

Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!

Find Model Engineer & Model Engineers' Workshop

Latest Forum Posts
Support Our Partners
Eccentric July 5 2018
Eccentric Engineering
Subscription Offer

Latest "For Sale" Ads
Latest "Wanted" Ads
Get In Touch!

Do you want to contact the Model Engineer and Model Engineers' Workshop team?

You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.

Click THIS LINK for full contact details.

For subscription issues please see THIS LINK.

Digital Back Issues

Social Media online

'Like' us on Facebook
Follow us on Facebook

Follow us on Twitter
 Twitter Logo

Pin us on Pinterest