UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Specific Vintage Equipment > Other Vintage Household Electrical or Electromechanical Items

Notices

Other Vintage Household Electrical or Electromechanical Items For discussions about other vintage (over 25 years old) electrical and electromechanical household items. See the sticky thread for details.

Reply
 
Thread Tools
Old 2nd May 2021, 2:51 pm   #1
factory
Heptode
 
Join Date: Jul 2009
Location: Cheshire, UK.
Posts: 869
Default Keith Blackman motor wiring

I've been helping my Dad with clearing out my Grandad's shed & garage over the last few weekends, we bought back a few motors yesterday including a Keith Blackman (seem to have made fan & blowers according to Graces guide) one.

Question is does anyone recognise the terminal letters so we can try it?
The terminals are labelled S, R & M, there may or may not have been a fourth connection.

David
Attached Thumbnails
Click image for larger version

Name:	DSC_4246a.jpg
Views:	112
Size:	152.8 KB
ID:	233086   Click image for larger version

Name:	DSC_4247a.jpg
Views:	133
Size:	122.8 KB
ID:	233087  
factory is offline   Reply With Quote
Old 2nd May 2021, 3:20 pm   #2
TonyDuell
Dekatron
 
Join Date: Jun 2015
Location: Biggin Hill, London, UK.
Posts: 4,182
Default Re: Keith Blackman motor wiring

'S' and 'R' may be 'Start' and 'Run' refering to the ends of 2 windings to connect to a capacitor and/or centrifugal switch.

Have you tried measuring the resistance between the terminals?
TonyDuell is offline   Reply With Quote
Old 2nd May 2021, 7:00 pm   #3
factory
Heptode
 
Join Date: Jul 2009
Location: Cheshire, UK.
Posts: 869
Default Re: Keith Blackman motor wiring

Taking off the test lead resistance I'm getting approx 6Ω between any combination of the terminals, there is nowhere to attach a capacitor that I can see and the terminal cover is threaded to go straight into conduit.

David
Attached Thumbnails
Click image for larger version

Name:	DSC_4255a.jpg
Views:	80
Size:	140.1 KB
ID:	233098   Click image for larger version

Name:	DSC_4257a.jpg
Views:	86
Size:	87.4 KB
ID:	233099  
factory is offline   Reply With Quote
Old 2nd May 2021, 7:26 pm   #4
John_Dw
Tetrode
 
Join Date: Dec 2020
Location: Stevenage, Hertfordshire, UK.
Posts: 60
Default Re: Keith Blackman motor wiring

Quote:
Originally Posted by factory View Post
Taking off the test lead resistance I'm getting approx 6Ω between any combination of the terminals, there is nowhere to attach a capacitor that I can see and the terminal cover is threaded to go straight into conduit.

David
I used Keith Blackman blowers and fans on gas fired web-offset print dryers in the 1970's. As the fans were a high centrifugal load, we ran the fan motors via a timer relay, with a change over between 'Start' and 'Run' at a specified time, dependent on the fan and HP of the motors....
John_Dw is offline   Reply With Quote
Old 2nd May 2021, 9:00 pm   #5
Radio Wrangler
Moderator
 
Radio Wrangler's Avatar
 
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 17,610
Default Re: Keith Blackman motor wiring

There doesn't seem to be a housing on that motor for a centrifugal switch, nor for connections from an internal one.

1400rpm says it's a 4-pole induction motor. S & R say it's for single phase. So it either has a capacitor start/capacitor run arrangement, or it has a timed start.

There are no facilities for mounting a capacitor outside the connection box. With the windings hard-commoned there aren't facilities for reversing it, either.

It looks to have been damp. The bearings might be doubtful.

David
__________________
Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done
Radio Wrangler is online now   Reply With Quote
Old 2nd May 2021, 11:06 pm   #6
Refugee
Dekatron
 
Refugee's Avatar
 
Join Date: Apr 2012
Location: Worksop, Nottinghamshire, UK.
Posts: 5,025
Default Re: Keith Blackman motor wiring

It looks like it might have had a contactor with two coils with a latching one on the (R)un terminal and a non latching coil on the (S)tart terminal.
You just push the start button and both windings are connected until you let the button go.
It just blows the fuse if you hold the button for too long.
Control gear was simple in old times.
Refugee is online now   Reply With Quote
Old 2nd May 2021, 11:09 pm   #7
Lucien Nunes
Octode
 
Lucien Nunes's Avatar
 
Join Date: Apr 2008
Location: London, UK.
Posts: 1,959
Default Re: Keith Blackman motor wiring

Some random thoughts:

Keith Blackman made at least some of their motors in-house, not sure whether all. They were a large concern with multiple sites making all kinds of ventilation plant and ancillaries.

It's a totally-enclosed motor that might have been in the fan's airflow, in which case the capacitor (if required) might have been remotely located. That is about the only good reason for having three terminals. The resistance readings are indicative of a capacitor motor (or a 3-phase winding re-purposed as single-phase.) A traditional split-phase switch-start motor would typically have two windings of different resistance sharing a common terminal, hence giving three different resistance readings one of which is the sum of the other two. There is sufficient room for a centrifugal switch in the end bell, however the line current is low at 2A for a 1/3hp 240V motor, suggesting capacitor run.

Can you confirm the resistance (and if possible, inductance) readings and perhaps prove that they are a mesh of three similar coils?

On a different note, is that a Century RSIR motor I see in the background?
__________________
Three anodes good, six anodes better!
Lucien Nunes is offline   Reply With Quote
Old 3rd May 2021, 7:48 am   #8
60 oldjohn
Nonode
 
Join Date: Dec 2004
Location: East Yorkshire, UK.
Posts: 2,955
Default Re: Keith Blackman motor wiring

Quote:
Originally Posted by Refugee View Post
It looks like it might have had a contactor with two coils with a latching one on the (R)un terminal and a non latching coil on the (S)tart terminal.
You just push the start button and both windings are connected until you let the button go.
It just blows the fuse if you hold the button for too long.
Control gear was simple in old times.
Sounds similar to our old drying plant. It had a large lever switch, centre position was off, pull down to Start position for about 10 seconds until fan reached nearly full speed then quickly lift lever to lock it in top position. If you got it wrong the lever was blocked from reaching the upper Run position, and you had to have to do it all again.
No capacitor that I know of.

John.
__________________
My favourite text message "I'll be there in five minutes, if not read again"
60 oldjohn is offline   Reply With Quote
Old 3rd May 2021, 8:04 am   #9
Mike Phelan
Dekatron
 
Mike Phelan's Avatar
 
Join Date: Nov 2003
Location: Near Leeds, West Yorkshire, UK
Posts: 4,434
Default Re: Keith Blackman motor wiring

Like the arrangement in John's post, in the 1960's this was a "Memota" made by Memrex, but these were three phase motors with connections with star for start and delta for run.

It's possible that David's single phase motor has a similar arrangement without a capacitor or centrifugal switch but just different start and run stator windings.
__________________
Mike.
Mike Phelan is offline   Reply With Quote
Old 3rd May 2021, 9:09 am   #10
Lucien Nunes
Octode
 
Lucien Nunes's Avatar
 
Join Date: Apr 2008
Location: London, UK.
Posts: 1,959
Default Re: Keith Blackman motor wiring

Although, if the resistances are 6Ω between any two terminals, that would be unusual for a split-phase switch-start, be it manual or centrifugal. The start winding usually has significantly higher resistance, and the readings would reveal the two windings sharing a common terminal by one reading being the sum of the other two. What the present readings suggest to me is that it is actually a delta winding, intended to run on a single-phase supply with a capacitor permanently in parallel with one coil. I am not sure why they would do that in this application but it will be interesting to further confirm the symmetry of the readings.
__________________
Three anodes good, six anodes better!
Lucien Nunes is offline   Reply With Quote
Old 3rd May 2021, 9:54 am   #11
60 oldjohn
Nonode
 
Join Date: Dec 2004
Location: East Yorkshire, UK.
Posts: 2,955
Default Re: Keith Blackman motor wiring

Quote:
Originally Posted by Mike Phelan View Post
Like the arrangement in John's post, in the 1960's this was a "Memota" made by Memrex, but these were three phase motors with connections with star for start and delta for run.

It's possible that David's single phase motor has a similar arrangement without a capacitor or centrifugal switch but just different start and run stator windings.
Oops, re #8, yes these were 3 phase motors.

John.
__________________
My favourite text message "I'll be there in five minutes, if not read again"
60 oldjohn is offline   Reply With Quote
Old 3rd May 2021, 10:23 am   #12
Station X
Moderator
 
Station X's Avatar
 
Join Date: Jan 2003
Location: Ipswich, Suffolk, IP4, UK.
Posts: 18,071
Default Re: Keith Blackman motor wiring

Quote:
Originally Posted by factory View Post
Taking off the test lead resistance I'm getting approx 6Ω between any combination of the terminals, there is nowhere to attach a capacitor that I can see and the terminal cover is threaded to go straight into conduit.

David
Those readings seem both low and odd to me. I'd have expected M to be the common point of the two windings. Perhaps the motor has internal shorts?
__________________
Graham. Forum Moderator

Keep the soldering iron hot.
Station X is online now   Reply With Quote
Old 3rd May 2021, 1:50 pm   #13
factory
Heptode
 
Join Date: Jul 2009
Location: Cheshire, UK.
Posts: 869
Default Re: Keith Blackman motor wiring

Thanks for all the replies.

It's possible it may have a short somewhere, some things my Grandad kept have proved to be knackered.

Quote:
Originally Posted by Radio Wrangler View Post
There doesn't seem to be a housing on that motor for a centrifugal switch, nor for connections from an internal one.

1400rpm says it's a 4-pole induction motor. S & R say it's for single phase. So it either has a capacitor start/capacitor run arrangement, or it has a timed start.

There are no facilities for mounting a capacitor outside the connection box. With the windings hard-commoned there aren't facilities for reversing it, either.

It looks to have been damp. The bearings might be doubtful.

David
As it's an enclosed motor it may well have been used outside, or stored badly over the years. If it was part of a ventilation/blower unit it may have been intended to be fixed rotation.

Quote:
Originally Posted by Lucien Nunes View Post
Some random thoughts:

Keith Blackman made at least some of their motors in-house, not sure whether all. They were a large concern with multiple sites making all kinds of ventilation plant and ancillaries.

It's a totally-enclosed motor that might have been in the fan's airflow, in which case the capacitor (if required) might have been remotely located. That is about the only good reason for having three terminals. The resistance readings are indicative of a capacitor motor (or a 3-phase winding re-purposed as single-phase.) A traditional split-phase switch-start motor would typically have two windings of different resistance sharing a common terminal, hence giving three different resistance readings one of which is the sum of the other two. There is sufficient room for a centrifugal switch in the end bell, however the line current is low at 2A for a 1/3hp 240V motor, suggesting capacitor run.

Can you confirm the resistance (and if possible, inductance) readings and perhaps prove that they are a mesh of three similar coils?

On a different note, is that a Century RSIR motor I see in the background?
Yes I can recheck the resistance and try measuring the inductance with one of the LCR bridges here (no idea how good the readings will be as none have been checked on inductance, I have decade boxes for checking R & C). This may have to wait till next weekend as it's raining.

And yes there is a Century repulsion start motor in the background, the spec plate is missing but it does have a plate for the sales agent "Swedish General Electric Ltd." which dates it to somewhere between 1915 & 1928 according to Graces Guide, it's also fairly rusty & caked in sawdust from being stored in the woodworking shed.

David
factory is offline   Reply With Quote
Old 3rd May 2021, 4:02 pm   #14
Refugee
Dekatron
 
Refugee's Avatar
 
Join Date: Apr 2012
Location: Worksop, Nottinghamshire, UK.
Posts: 5,025
Default Re: Keith Blackman motor wiring

I would be tempted to wire it up with a convector heater like a lamp limiter and with an insulated probe touch the start winding to the run winding.
Refugee is online now   Reply With Quote
Reply

Thread Tools



All times are GMT. The time now is 1:48 pm.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2021, vBulletin Solutions, Inc.
Copyright ©2002 - 2021, Paul Stenning.