Coreless Motors

    Could someone confirm that a "Coreless" motor simply lacks a yoke? If this is the case, is the purpose technical or commercial?
Regards
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

My understanding of the terminology is that the yoke holds the pole pieces together and is often part of the frame or casing, so the answer to your question is no.
In a "normal" motor, the armature windings are wound around a core which gives the armature greater momentum and thermal mass.
A coreless motor literally has no core. The armature is simply the windings. The lower mass means they can respond much more quickly to changes in voltage. The lower thermal mass is one reason they are said to be unhappy when fed too low a frequency of pulsed waveform.
Andrew
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Peter Abraham wrote:

Purpose is technical. They have very low interia, no cogging. They are the engineering choice for expensive (thousands to millions of pounds) precision instruments where such behaviour is required. They have some uses in model railway propulsion, if married to appropriate gearing.
Design. In most cases, the armature is just a wire basket, there is no central "core" to the motor. This is what gives it the low inertia. In some designs, the fixed magnet is placed within the centre of the basket. The winding basket design means there are no specific "poles", so the motor does not "cog".
Years ago, I edited a short work on making ones own motors, which covered "normal" and "coreless" designs. I might translate it for the internet sometime, though its value is only historical, as cheap quality small motors are available commercially.
- Nigel
--
Nigel Cliffe,
Webmaster at http://www.2mm.org.uk/
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Nigel Cliffe wrote:

But as true background info that would be very valuable. Please let me be the first to encourage you to do this.
-- Rod
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I have a Wills (yes, Wills, not SEF ;-) ex-SECR H class kit that I built back in the late 80s, and it has a Portescap RG4 in it. When I run it (which is not very often at the moment) it is very smooth. I'm wondering how best to convert it to DCC though. What would be the motor settings on a Lenz Gold to best suit??
--
Ian J.

'Who knows what the tide could bring?'
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Ian J. wrote:

General view is that the noiseless Lenz models are fine. I think that includes the Gold models.
Try asking the JMRI (Decoder Pro), or the DCCUK Yahoo group for opinions on best settings.
--
Nigel Cliffe,
Webmaster at http://www.2mm.org.uk/
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Nigel Cliffe wrote:

It largely depends on the decoder output frequency. If the output frequency is 16kHz or more the decoder may be used for coreless micro motors.
--
Venlig hilsen
Erik Olsen
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.