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Motor wiring

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Phil Boyland04/06/2018 21:31:51
49 forum posts
13 photos

Hi there. Gotten myself a Super 7 and the motor wasn't attached so trying to work out what to do. I've kept my original stand and controller, a Myford one with emergency stop and the contacts are U1, U2, Z1 & U2 + an Earth.

I am after some advice on which motor wire is which as a tad confused on getting it plummed in. I'm not an electrician obviously, but am competent once I get instructions from someone wiser than me cool

It's a Tyco/Crompton 240V and the pic shows exactly how it came to me, apparently unused. Cap isn't attached currently but I know the Red/Green wires are for that and top post is Z2.

Thanks in advance




Brian Sweeting05/06/2018 13:18:10
443 forum posts
1 photos

The diagram from the motor cover gives you the wire positions as far as I can see.

Red, black, yellow and the cap.

Ian Parkin05/06/2018 14:58:01
839 forum posts
202 photos


Your red/green wires one of which is connected to z2 and the other one loose go to your capacitor ...they end in 1/4 spades.

Live to u1 and neutral to u2

Edited By Ian Parkin on 05/06/2018 15:03:25

Edited By Ian Parkin on 05/06/2018 15:03:46

Phil Boyland05/06/2018 19:02:29
49 forum posts
13 photos

Thanks for the replies, so a few more questions,

I presume I fit the bare ends under the corresponding posts, then fit my new flex on top of them?

Following the logic of the diagram, which of the wires will then go to Z1 of the control switch as there isn’t one in the motor.

Phil Boyland05/06/2018 19:22:05
49 forum posts
13 photos

Another question, my ML7 had a 5 wire cable going to the control switch, so again following from the diagram, do I only need 3 core for this motor?

Glyn Davies05/06/2018 19:53:29
121 forum posts
35 photos

I was faced with a similar problem when trying to wire an imported motor to a Dewhurst reversing switch. I hadn't appreciated that both sides of the start winding centrifugal switch are connected to terminals in the connector box. In my confusion, I managed to wire the incoming live and neutral across the switch. Not a good idea.

The basics are that a capacitor start motor has a run winding that has a resistance of 3 ohms or so and needs a live and neutral across it. The start winding also needs a live and neutral across it but has a slightly higher resistance and has a capacitor and a centrifugal switch in series with it. Swapping the live and neutral across the start winding reverses the motor direction of rotation. In my case, one of the loose wires was one end of the start winding and the other was a short wire from the output side of the centrifugal switch. I therefore needed to make two soldered and heat shrink sleeved connections - wire from switch to capacitor and capacitor to start winding. The two pairs of lives and neutrals could then be attached to four of the terminal posts.

If you see what I mean...

In your case, it looks as though the run winding is connected to U1 and U2, but why you have three loose wires as well as the cap wires is a puzzle and you might need a ohm meter to figure what's what.

Glyn Davies05/06/2018 20:24:48
121 forum posts
35 photos

Just had another look at your pic - it looks as though R and P are the centrifugal switching connections - there should be zero ohms across them. It also looks as if blue and yellow are the ends of the start winding and red and black the run winding. Confirm with an ohm meter. If so, you should connect the red/green cap wire to R, the red wire to U1, and the black to U2. You then need to connect the live run supply to U1 and the neutral run supply to U2. The live start supply goes to P and the neutral start supply to the yellow wire. Hopefully one of the screw studs is not connected to anything in the motor and can be used to connect these two.

If you don't have a reversing switch, bridge U2 and P and connect the yellow wire to U1. Then connect the live from your switch to U1 and the neutral to U2.

If you follow these instructions, stand well back when switching on.



Edited By Otley on 05/06/2018 20:28:25

Edited By Otley on 05/06/2018 20:52:55

Mike Poole05/06/2018 22:36:57
2746 forum posts
64 photos

Some more details of the switchgear you want to connect the motor to would help people to give a more helpful reply, I would think if your previous motor had a five wire connection then you had a reversing switch, if you wish to have this facility with this motor a bit more info would be helpful.


Phil Boyland05/06/2018 22:38:16
49 forum posts
13 photos

Thanks Otley, will give it a try and let you know findings. I do have a reverse switch in the unit.

Will all 4 connections in my control switch be used or just 2 of them? (ignoring earth for now)

Phil Boyland05/06/2018 22:42:46
49 forum posts
13 photos

The control switch is a Myford 85766, the same a Clive Hartlands in this thread.



Edited By Phil Boyland on 05/06/2018 22:46:35

Phil Boyland05/06/2018 22:46:01
49 forum posts
13 photos

I can take a pic inside of it if required.

Edited By Phil Boyland on 05/06/2018 22:47:04

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