Jolly Green Monster 2

Anyone know where I can get a 240volt electric motor recoiled?

Need to fix the heating which doesn't work without a fan..

cheers

JGM

David_Wallis

rewound??

let me know if you find someone..

David

Jolly Green Monster 2

Yeah sorry.. rewound.. I was on alternators with recoiled.. doh..

currently it shorts to earth.. blasted thing.. it is off an old oil central heating boiler... might be time to buy a new boiler I fear... not going to be a cheap month that is for sure.

JGM

David_Wallis

can you not just buy a new motor??


David

Jolly Green Monster 2

Possibility I suppose.. don't seem to be able to get them though as it is an old Woods motor apparently.. means nothing to me..

I suppose if I bolt the fan that I have on a new then it should blow a similar volume.. has some spec like 2650rpm etc.. I have full details at home just never heard of someone manuafacturing them to a spec you give but it must be possible though.. especially as the new boiler is 700pound plus a few days work for me to fit it..

JGM

David_Wallis

Machine mart do them... what sort of size is it...

1/3hp ?? they do 2 pole and 4 pole.. (sounds like 2 pole with that speed IRC) May have to worry about starters with those motors..

David

carl

Depends where you are, but the company my mum works for does this (rewinding, recoiling, whatever). Apparently they also do aluminium welding; a fact I discovered after I had to wait a week to have a cylinder head ally welded

http://www.fyfewilson.co.uk/

alcazar

iTrader: (2)

Have a look in Yellow Pages, under "electric motor repairs".
I got one redone, including new bearings, for about £25 last year. It was a little one off an Emco lathe. Took about 3 days from taking it in to picking it up. It now runs like silk.
Alcazar

323GTR

Where abouts are you? Look up Dowding and Mills, they have places all over the country and do rewinds. It's usually not much different in price to buy a new one. Other than that, there are loas of small rewind shops about around the country, if you have no joy, mail me your details and I'll send you details of a place nearby.

logiclee

JGM,

I deal with a number of firms that do specialist rewinds. Its going to cost around 200 - 300 pounds though for a one off rewind and bearing replacement.

Look up Lewis Berls in Chesterfield.

You would be a lot better getting a replacement motor even if you have to have an adaptor plate or something manufactured.

Lee

[Edited by logiclee - 10/21/2002 3:55:20 PM]

Jolly Green Monster 2

Thanks for your replies guys..

I didn;t think I would get much response so I am shocked..

I am happy to knock up a plate to make it fit or something I shall have to work out what I need and check the places suggested.

To Davids question 2pole? 4 pole? it has a positive and negative connection rather than two and two but I am sure you meant something else inwhich case I don't know.

JGM

323GTR

The poles are to do with the internal windings, and affects the speed the motor runs. 2650 Rpm sounds about right for a small 2pole motor. If it's single phase, they usually have a capacitor starter, and these can fail on their own, leaving the motor still ok. Best bet is just to take it in to the nearest place, they'll check it and give you the good / bad news.

matt.bowey

If you give a 2 pole motor 50Hz, you must get 3000rpm! Nothing more, nothing less!

logiclee

Matt,

Only in theory, motors have different slip characteristics so anything from 2600rpm to nearly 3000rpm is possible.

Lee

David_Wallis

if it has + and - it is not an AC motor..

David

matt.bowey

Thats a hell of a lot of slip!! I've never heard of an induction motor with 15% slip!

AC motors do have a + or -, otherwise the direction of rotation would reverse!

323GTR

That amount of slip is normal for a low kW motor. Some high torque motors have even more...

Jolly Green Monster 2

Well it does have + and - or rather red and white wires... and like suggested above it is a fan motor so need to blow rather than suck (oooeeerrr)..

It was sent off to a repair place who said it was shorting to earth and so they couldn't fix it.. which confused the flip out of me because I was under the impression they were going to rewind it etc.. which was somewhere the local heating specialist shop sent it too.. they are now suggesting I try somewhere that might be able to rewind it.. so where they sent it I dunno..

Does Machine Mart have a website?

BTW - 50hz does ring a bell but I cannot access the service manual for the boiler which has the complete spec in until the weekend..
Definitly remember 2650rpm though..

Cheers

JGM

motorman

JGM,

Try http://www.machinemart.co.uk/, from memory I think Screwfix also do small 240V motors. When you're down in Kent then Mid Kent Electrical, 1st.Rewinds (Ashford) and MCD Rewinds Aylesford could be worth a try, but from experience the cost of a repair can be greater than the cost of a new small motor.

Jon

Jolly Green Monster 2

Thanks Motorman..

JGM

Jolly Green Monster 2

I think I need to check the spec of the motor but looking at
http://www.machinemart.co.uk/ranges.asp?g=104&r=2026
click the table.. they have varying shaft sizes but I am pretty sure my motor only has about a 5mm shaft.. no idea what Frame Size is and measured in 'L' ?

Starter required? it has a capaciter wired separately which I assumed was to stop it interferring with the TV? could that be the starter?

I think the most likely looking replacement has an 11mm shaft (I shall have to drill the blades etc to fit) is 2pole so hopefully near the 2650rpm although they state 3000rpm, is frame size 63?
requires 2-4 starter? is 1/3 hp and only 47pound basically..

Worry is that if it runs too fast an RPM then the boiler flame will either blow out of be too big.. can but see..

Father inlaw has access to a machine shop so shouldn't be a problem adapting the motor to fit the old frame or make a new one.

Nothing is ever straight forward is it..

JGM

logiclee

No

The capacitor will be the starter, may be as well ordering a new one from Machine Mart to go with the new motor, should'nt be expensive.

Lee

Jolly Green Monster 2

Sounds sensible.. cheers

JGM

Jolly Green Monster 2

Right.. got the info from the manual for the motor..

Single Phase, Shaded Pole, 2650rpm, bearings are bronze sleave type.

Anyone know what Shaded Pole means?

Sounds like the single phase from Machine mart with 3000rpm and cost of 70pounds including a starter seems good.

Anyone like to elaborate on how it can run at 2650rpm rather than 3000rpm? if it runs 350rpm faster not sure it will make much of a difference to air throughput with a 4.8inch (121mm) fan attached.
I suppose if it runs too quick I can adapt the fan..

Or best quote for 120pounds to rewind the current motor although that could increase if more work is required which is likely seeing as it is at least 20years old.

JGM

matt.bowey

Shaded pole means that part of the poles will be covered in copper, known as a shading coil. This will set up a rotating field in the pole itself, just enough to get the rotor moving, leading to a reduction in starting torque.

If you connect a single phase induction motor to 50Hz mains, its stator filed will rotate in line with the equation: f=n.p/60, where f=frequency, n=rotation speed & p=pole pairs.

So, n=f.60/1

Hence 3000rpm for a 50Hz motor.

However, the rotor cannot rotate at this (synchronous)speed. It must lag by a small amount, usually by 100-200 rpm for a motor of this type. This is know as slip.

Sure, the air flow will be greater, but you should be able to live with that.

[Edited by matt.bowey - 10/23/2002 1:15:42 PM]

Jolly Green Monster 2

Cheers Matt..

It might blow the flame out on the boiler but more likely just cause a slightly larger flame.. but then I can easily tell if this is the case as the heating will be hotter etc.. I could block part of the air duct etc.. to adjust it.. Sounds sensible..

If I had known it would have been this much hassle the 700pound new boiler might have been easier (although 10times more expensive of course)

Thanks for you help

JGM

Jolly Green Monster 2

Just ordered a motor and starter from Machine Mart...

Awaiting it's arrival to see if it is a possible fit or not..

Cheers

JGM

Toerag

There's a company called 'Industrial motor rewinds' over here that may be able to help?
01481 722726
fax 01481 721488

matt.bowey

The guy next to me at work used to work on Gas Turbine engines (a big fan!). He thinks that the amount of airflow will increase by the square of the speed. Another useless fact........!

Jolly Green Monster 2

Cheers for that..

If I just worked that out right then it is an increase of 1.7% airflow, which I think I can live with.. especially as one of the fins on the fan has a dig in it which must be reducing the air flow by similar percentage so sorted!

JGM