Printable Version | Subscribe | Add to Favourites
New Topic New Poll New Reply
Author: Subject: Rotary Convertor or Variable Frequency Drive. Which is best?
tilly819

posted on 10/10/20 at 09:06 AM Reply With Quote
Rotary Convertor or Variable Frequency Drive. Which is best?

Hi All.

I keep hearing this question come up on various facebook groups and web forums. So I have put together this little video in an effort to debunk some of the false information and give people the pros and conns of both devices. My hope is that this will allow home workshopers to make an informed decision so they don't end up wasting money on the wrong solution for their application. Hope you enjoy.







F20C Haynes roadster 440 BHP/Tonne www.youtube.com/handmadeextreme

View User's Profile View All Posts By User U2U Member
ianhurley20

posted on 10/10/20 at 08:35 PM Reply With Quote
Thank you for making the video Tilly - brilliant and helpful explanation of the options for 3 phase for those who will use it.







View User's Profile Visit User's Homepage View All Posts By User U2U Member
big_wasa

posted on 11/10/20 at 06:58 AM Reply With Quote
Interesting vid. With just one motor in my lathe it was a simple choice I thought. But It may be worth noting that multi Vfd’s may not be an option any way due to earth leakage.
The Rcd in my last house would only just cope with the one on the lathe. A second one for the coolant pump tripped it out every time. Despite a s/h 1/4hp Vfd only costing me £30 it’s lived in a box for several years.

View User's Profile View All Posts By User U2U Member
SteveWalker

posted on 11/10/20 at 12:57 PM Reply With Quote
quote:
Originally posted by big_wasa
Interesting vid. With just one motor in my lathe it was a simple choice I thought. But It may be worth noting that multi Vfd’s may not be an option any way due to earth leakage.
The Rcd in my last house would only just cope with the one on the lathe. A second one for the coolant pump tripped it out every time. Despite a s/h 1/4hp Vfd only costing me £30 it’s lived in a box for several years.


We had a similar problem with the RCD tripping due to the number of PCs, printers and accessories, all with mains filters that leak to earth. It was obviously near the limit and randomly tripped every so often - usually at some inconvenient time.

We solved our problem by ditching the RCD and replacing the MCBs for the circuits that it protected with miniature RCBOs that were the same size. Since then, as the various leaky loads are spread across a number of circuits rather than all combined together, we haven't had any trips.

View User's Profile View All Posts By User U2U Member
v8kid

posted on 11/10/20 at 01:00 PM Reply With Quote
Excellent Video.

Can I suggest some additions to your pro/con lists which may help making a decision.

1. Older machines tend to be designed around HSS tooling which has a lower cutting speed than Carbide. In this case a VFD can double the machine speed bringing the machine up to date and giving much better cutting in some circumstances.
2. Coolant pumps have a low starting torque requirement which makes them ideal for fixed capacitor 3 phase conversion costing less than a tenner including case. Plenty youtube vids on the subject
3. Single-phase motors are not that expensive particularly the smaller sizes and they all have standard frame sizes.
4. Be careful when specifying VFD the majority are for star connected 3 phase motors which only require 240V whilst delta motors require 415V. Not all motors can be converted from delta to star.
5. Another option for traverse motors is to use stepper/servo motors which are cheap (stepper) and operate off cheap SMPS power supplies and controllers. Added advantage of future CNC control.


Cheers!





You'd be surprised how quickly the sales people at B&Q try and assist you after ignoring you for the past 15 minutes when you try and start a chainsaw

View User's Profile E-Mail User Visit User's Homepage View All Posts By User U2U Member

New Topic New Poll New Reply


go to top






Website design and SEO by Studio Montage

All content © 2001-16 LocostBuilders. Reproduction prohibited
Opinions expressed in public posts are those of the author and do not necessarily represent
the views of other users or any member of the LocostBuilders team.
Running XMB 1.8 Partagium [© 2002 XMB Group] on Apache under CentOS Linux
Founded, built and operated by ChrisW.