Author Topic: Dynamo troubles.  (Read 2061 times)

Online berger

  • Wise & Enlightened
  • *
  • Join Date: Nov 2017
  • Posts: 3201
  • Karma: 22
  • keith.uk 500sscafe.norbsa JDM honda 750fz
Re: Dynamo troubles.
« Reply #15 on: 15.01. 2024 22:14 »
just a thought some carbons are no good and even only fit for the bin even before they have been fitted,

Online raindodger

  • Moving Up
  • **
  • Join Date: Sep 2010
  • Posts: 46
  • Karma: 0
Re: Dynamo troubles.
« Reply #16 on: 23.01. 2024 09:50 »
Checked the carbons, 0 ohms from pigtail loop to rubbing face.
I think I'll take it back to Drags and find out how they get 28 volts.
Regards.
Tim.

Offline limeyrob

  • Resident Legend
  • *****
  • Join Date: Nov 2023
  • Posts: 899
  • Karma: 4
Re: Dynamo troubles.
« Reply #17 on: 23.01. 2024 10:39 »
0 Ohms is good.
Slough 59 GF/SR

Online raindodger

  • Moving Up
  • **
  • Join Date: Sep 2010
  • Posts: 46
  • Karma: 0
Re: Dynamo troubles.
« Reply #18 on: 24.01. 2024 10:03 »
Hello, Groily and Swarfy.
Thanks for the comrehensive advise.  I'm going to bite the bullet and take my test leads,
meter, drill and the dynamo to Drags next week.  This has gone on long enough.
Watch this space.

Regards.
Tim.

Online chaterlea25

  • Wise & Enlightened
  • *
  • Join Date: Jun 2009
  • Posts: 4116
  • Karma: 54
Re: Dynamo troubles.
« Reply #19 on: 25.01. 2024 16:07 »
Hi Tim,
No real way to identify the field winding ends when the coil is fitted, the way it works is correct *ex* *ex*
I think that 12 ohms is high resistance value for the field coil??
Does anyone have a 12v dynamo apart to check the value?
I'm not sure if I have one???? Must look

John
1961 Super Rocket
1963 RGS (ongoing)

Online groily

  • Wise & Enlightened
  • *
  • Join Date: Jul 2007
  • Posts: 1945
  • Karma: 33
    • www.brightsparkmagnetos.com
Re: Dynamo troubles.
« Reply #20 on: 25.01. 2024 19:04 »
I think that 12 ohms is high resistance value for the field coil??
Does anyone have a 12v dynamo apart to check the value?
John

Yup.
Just measured three new unused 12v ones, UK-made and all are 12 ohms +/-   . . .which is what I expect to see with them.
6v ones at a tad under 3 ohms typically, also as expected  . . . and per Lucas at 2.8 /2.9 ohms (iirc).
Bill

Offline trevinoz

  • Newcastle, N.S.W. Australia.
  • Wise & Enlightened
  • *
  • Join Date: Jul 2006
  • Posts: 3226
  • Karma: 71
Re: Dynamo troubles.
« Reply #21 on: 25.01. 2024 20:35 »
My 12V field coils are about 11 Ohms. I used to wind them to 5.6 Ohms, and they were fine, but with the higher resistance the I squared R losses are much reduced resulting in less heat generated.

Offline CheeserBeezer

  • Valued Contributor
  • ****
  • Join Date: Dec 2021
  • Posts: 485
  • Karma: 15
    • Priory Magnetos Ltd
Re: Dynamo troubles.
« Reply #22 on: 25.01. 2024 23:18 »
Hi. I'm happy to check it out f.o.c. Just send it to me and I'll tell you how it performs on my tester. 10 ohms is correct (or thereabouts) for a 12v field coil.

Online raindodger

  • Moving Up
  • **
  • Join Date: Sep 2010
  • Posts: 46
  • Karma: 0
Re: Dynamo troubles.
« Reply #23 on: 30.01. 2024 18:47 »
Dear all.
           I'm an idiot!!  I was not spinning it fast enough, that's all.
Increased the speed and all was well.
Thanks for all the advice, it's all sorted now.  Hooray!!

Regards to all.
Tim.

Online groily

  • Wise & Enlightened
  • *
  • Join Date: Jul 2007
  • Posts: 1945
  • Karma: 33
    • www.brightsparkmagnetos.com
Re: Dynamo troubles.
« Reply #24 on: 30.01. 2024 19:02 »
Thought you told us you were spinning it 'at 3000rpm anti-clock'? Was there a 0 missing!?
Anyway, glad it works.
Bill

Online raindodger

  • Moving Up
  • **
  • Join Date: Sep 2010
  • Posts: 46
  • Karma: 0
Re: Dynamo troubles.
« Reply #25 on: 01.02. 2024 08:41 »
Yes, Idid say that but I was mistaken. 
The drill is very old and makes the same noise no matter what gear is selected.
However, all is well!!

Regards.
Tim.

Online groily

  • Wise & Enlightened
  • *
  • Join Date: Jul 2007
  • Posts: 1945
  • Karma: 33
    • www.brightsparkmagnetos.com
Re: Dynamo troubles.
« Reply #26 on: 01.02. 2024 09:41 »
 *smil* *smil* *beer* *beer*
Bill