What core cable.

This topic has 14 replies, 7 voices, and was last updated 16 September 2022 at 15:49 by Bazyle.

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2 September 2022 at 15:37 #612106
Haydn Callow
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@haydncallow19480
Me again with another beginners question :- I have just got myself a Gryphon 0.25 hp motor. I want to keep it as a spare for my ML7 lathe.

it has come after having had new bearings fitted and runs very quiet and smooth.

it also came with a 3 core cable and plug and runs in one direction only.

I would like to rewire it so I can select Fwd/Rev using a drum switch.

I have a drum switch with 2 rows of 4 contacts.

the motor has 4 terminals. Z1. Z2. A1. A2

A1 seems to be connected to Z1 via a copper link

A2 seems to be connected to Z2 via a copper link

how ‘very simply please’ do I connect the Mains, Drum switch and motor together to achieve what I want and how many cores does the cable need from motor to switch, and if possible how thick do the cores need to be ? I.e. .75mm,1mm, 1.5mm

long question but I am learning and you have sorted my previous 2 ??s very quickly

thanks
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2 September 2022 at 15:37 #32280
Haydn Callow
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@haydncallow19480
2 September 2022 at 15:46 #612107
John Haine
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@johnhaine32865
That's possibly a bit small for a ML7, however…

Does it have an obvious capacitor? If it does then it should be reversible in the way you want.

As for using it as a spare, induction motors almost never give up unless either the bearings wear out or the start/run capacitor(s) give up, usually the latter. So your main motor is very likely to be easily repairable if it does go.
2 September 2022 at 15:57 #612108
Haydn Callow
Participant
@haydncallow19480
Thanks,

yes it does have a capacitor…. The motor is I understand original to a ML7. The motor on my lathe was new a month ago and gave up….it would only go in reverse…..see my previous topic…the manufacturer is replacing it for me.
2 September 2022 at 16:02 #612109
John Haine
Participant
@johnhaine32865
Well without knowing exactly how the cap is connected I'm not sure how you reverse it, but I would guess that one winding must be Z1-Z2 and the other A1-A2, and one of these has the cap in series. At the moment it's connected Z1-A1 and Z2-A2, I would guess that if you connect Z1-A2 and Z2-A1 it would run in reverse as you have reversed one winding's sense relative to the other. As for the number of cores, there are only 4 terminals (plus earth presumably) so it can't be more than 4! As for size the same size as on your main motor. Wiring these funny switches I have no knowledge of I'm afraid.
2 September 2022 at 16:11 #612110
peak4
Participant
@peak4
Here you go, not only will this site show you how to refurbish a Dewhurst switch, it will also show how to wire one.
https://misterlinnsworkshop.wordpress.com/2014/03/08/dewhursts-big-switch/

Re. the number of cores in the cable, I'd go for 5 core, as you need 4 plus an earth.
You could use 4 core and earth separately, but if you need to buy some cable anyway………………

Bill

Edited By peak4 on 02/09/2022 16:14:10
2 September 2022 at 16:13 #612111
Haydn Callow
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@haydncallow19480
The capacitor is connected to Z1 & Z2. Red wires

the windings to A1 & A2 Black wires
2 September 2022 at 16:21 #612113
Haydn Callow
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@haydncallow19480
Peak4….great, thanks…..

Edited By Haydn Callow on 02/09/2022 16:22:10
2 September 2022 at 16:55 #612116
noel shelley
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@noelshelley55608
A .25Hp motor will only do small work on an ML7 ! Should be 0.5Hp Start windings should be blue and Yellow, run windings should be red and black. It sounds like a dewhurst drum switch. A1 and A2 run and Z1 and Z2 start ' 1,2,3,4, on left 5.6.7.8. on right of switch.. Live to No1 Neutral to No3 earth to the earth stud or bear metal point VITAL ! A1 to No5, A2 to No 7, Z1 to No6 and Z2 to No2. IF the direction is wrong on the switch swap No6 and No2.. ONLY use this switch to change direction of rotation, stop and start with a seperate switch. NEVER change direction whils the motor is still turning ! . Good luck Noel.

Edited By noel shelley on 02/09/2022 17:33:23
2 September 2022 at 17:37 #612119
Haydn Callow
Participant
@haydncallow19480
Thanks for that….it’s not a Dewhurst but very similar…..made in China , green oblong….plenty to see on eBay….dammed if I can work out how to post a picture on here. I’m on a iPad
2 September 2022 at 17:38 #612120
noel shelley
Participant
@noelshelley55608
To answer your question 5 core 1.5 mmsq Noel..
2 September 2022 at 18:22 #612123
not done it yet
Participant
@notdoneityet
Posted by noel shelley on 02/09/2022 17:38:58:

To answer your question 5 core 1.5 mmsq Noel..

I would think 1mm ^2 or even less,is likely sufficient. It’s not much bigger than a good sized soldering iron!🙂
2 September 2022 at 22:12 #612151
SillyOldDuffer
Moderator
@sillyoldduffer
I'd think twice before fitting a motor that small – it will limit how fast you can work, and the motor will often be pushed to the max. Half to one horse-power is more usual, and a boy racer might go bigger still…
16 September 2022 at 13:50 #613780
Haydn Callow
Participant
@haydncallow19480
All good and working well, thanks everyone
16 September 2022 at 15:49 #613800
Bazyle
Participant
@bazyle
Hope you are not using the drum switch as the main on/off. That will burn the contacts – you need to get a 'no volt release' unit. Probably got that in the Myford wiring but in case you decided to use this motor on some other little project.
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