My 54 G80S has the usual Lucas E3-N dynamo. Presently I can't get any output on my multimeter. I have tested as per Matchless workshop manual. Remove the 2 wires and connect them. With bike running put the +ve probe on any dynamo terminal and the -ve proble on an earth point. With the meter set to 0-20v no significant reading other than 0.4v
Before I remove the dynamo is there anything I can check? What's the most likely problem?
I'm new to dynamos so any advice appreciated.
Andy
Dynamo issues
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- Iron Head
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Re: Dynamo issues
I'm far from an expert Andy but, I believe, as long as the brushes and commutator are clean and making contact it can only be a fault in the armature or field coils. I did mine last year using the full kits of eBay and it was a really easy and enjoyable process. Take care with the Mazak end fitting which performs a lot structurally and is easily broken!
Iron Head
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Re: Dynamo issues
With respect, Andy, I don't think you have that quite right. You say "Remove the 2 wires and connect them.".... No. Remove the two wires from the dynamo and connect the two dynamo terminals together with a short length of wire. Unless somebody has changed it over, your bike would be positive ground so your multi-meter +ve probe should be connected to ground (earth) and the -ve probe should be connected to one of the two connected dynamo terminals.AndyO wrote:My 54 G80S has the usual Lucas E3-N dynamo. Presently I can't get any output on my multimeter. I have tested as per Matchless workshop manual. Remove the 2 wires and connect them. With bike running put the +ve probe on any dynamo terminal and the -ve proble on an earth point. With the meter set to 0-20v no significant reading other than 0.4v
Before I remove the dynamo is there anything I can check? What's the most likely problem?
I'm new to dynamos so any advice appreciated.
Andy
John
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- Harry44
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Re: Dynamo issues
Hi, the next easy check is the field coil resistance. Multimeter on ohms measured from the terminal to earth.
You looking for about 3.2 Ohms.
Cheers Harry
You looking for about 3.2 Ohms.
Cheers Harry
si is does non opportunus vos postulo a maior pango
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Re: Dynamo issues
Thanks for that Pharisee John. The wording in the manual is confusing. I'll try again tomorrow as well as checking ohms output as suggested.
Andy
Andy
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Re: Dynamo issues
I use a lamp instead of a meter. A lamp is a much better indicator of dynamo power output than a meter as even if you get a good voltage reading on the meter it won't indicate the dynamo's power under a load.
This is my test kit which I use for 6v and 12v systems. The 12v bulb should light brightly even on a 6v system since when doing the test the dynamo output is unregulated and will/should rapidly rise up to 20v with just 'normal starting off from a standstill' revs.
'D' and 'F' bridge the two 'sockets' at the end of the dynamo. 'Earth' goes to the frame or other clean metal part:
This is my test kit which I use for 6v and 12v systems. The 12v bulb should light brightly even on a 6v system since when doing the test the dynamo output is unregulated and will/should rapidly rise up to 20v with just 'normal starting off from a standstill' revs.
'D' and 'F' bridge the two 'sockets' at the end of the dynamo. 'Earth' goes to the frame or other clean metal part:
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Re: Dynamo issues
Go on , Sprid, show them the spark test rig again!
Johnny B
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Re: Dynamo issues
You're humouring me John56G80S wrote:Go on , Sprid, show them the spark test rig again!
Johnny B
You must be referring to the 'Spridspark', my self-powered digital magneto tester with the audible current strength guide:
"Hmm" = No output.
"Ouch!" = Weak.
"Yeeeeow!" = Good. (The current kit is supplied with a strip of plasters for the head wound after contact with the handlebars).
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Which taken at the flood............'
Which taken at the flood............'